Cefazolin is a parenteral first-generation cephalosporin indicated for respiratory tract, urinary tract, skin and skin structure, biliary tract, bone and joint, and genital infections as well as sepsis, endocarditis, and perioperative prophylaxis. Cephalexin has greater activity against gram-positive bacteria than most other cephalosporins. Similar to other first-generation cephalosporins, cefazolin is active against gram-positive aerobic cocci, but has limited activity against gram-negative bacteria. Cefazolin is the primary agent used for surgical wound prophylaxis in cardiothoracic, vascular, and orthopedic procedures and for the prevention of infective endocarditis in high-risk cardiac patients undergoing dental, respiratory, or infected skin/skin structure or musculoskeletal procedures who are unable to take oral medications.
General Administration Information
For storage information, see the specific product information within the How Supplied section.
Route-Specific Administration
Injectable Administration
-Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.
-Reconstituted solutions may range in color from pale yellow to yellow without a change in potency.
Intravenous Administration
Intermittent IV Infusion
Reconstitution/Preparation
Conventional Vials for Injection
-Reconstitute vials with Sterile Water for Injection according to the manufacturer's instructions.
-Shake well.
-Storage: Store reconstituted solutions at room temperature or under refrigeration according to the manufacturer's instructions.
Bulk Vials for Injection
-Reconstitute 10 g vial with 45 mL or 96 mL of diluent to yield 200 mg/mL and 100 mg/mL, respectively.
-Reconstitute 20 g vial with 87 mL of diluent to yield 200 mg/mL.
-Compatible IV solutions include Sterile Water for Injection, Bacteriostatic Water for Injection, or 0.9% Sodium Chloride Injection.
-Further dilution is required; pharmacy bulk vials are not intended for administration via direct IV injection.
-Storage: Use bulk vials within 4 hours of initial entry.
ADD-Vantage vials
-Reconstituted in 50 or 100 mL flexible containers with 0.9% Sodium Chloride Injection or 5% Dextrose Injection. ADD-Vantage vials are not to be used for direct IV injection or IM injection.
-Storage: The reconstituted solution is stable for 24 hours at room temperature.
Frozen Pre-mixed Bags
-Thaw frozen container at room temperature (20 to 25 degrees C or 68 to 77 degrees F) or under refrigeration (2 to 8 degrees C or 36 to 46 degrees F).
-Do not force thaw by immersion in water baths or by microwave irradiation.
-Storage: The thawed solution remains stable for 30 days under refrigeration (5 degrees C or 41 degrees F) or 48 hours at room temperature (25 degrees C or 77 degrees F). Do not refreeze.
DUPLEX Drug Delivery System
-Use only if container and seals are intact. To inspect the drug powder for foreign matter or discoloration, peel the foil strip from the drug chamber.
-Protect from light after removal of foil strip.
-Allow refrigerated product to reach room temperature before patient use.
-Unfold the container and point the set port downward. Starting at the hanger tab end, fold the container just below the diluent meniscus trapping all air above the fold.
-To activate, squeeze the folded diluent chamber until the seal between the diluent and powder opens, releasing diluent into the drug powder chamber.
-Agitate the liquid-powder mixture until the drug powder completely dissolves.
-Do not use plastic containers in series connections as this may result in air embolism due to residual air being drawn from the primary container before administration of the fluid from the secondary container is complete.
-Do not introduce additives into the container.
-Storage: If the foil strip is removed, refold container and latch the side tab until ready to activate and use within 7 days. After reconstitution (activation), use within 24 hours if stored at room temperature or within 7 days if stored under refrigeration.
Dilution
-ADD-Vantage vials: After reconstitution, no further dilution is required.
-Conventional/Bulk vials:
--Adults: Further dilute the reconstituted solution in 50 to 100 mL of a compatible IV solution according to the manufacturer's instructions.
-Pediatrics: Further dilute the reconstituted solution in compatible IV solution according to the manufacturer's instructions to a concentration of 10 to 40 mg/mL.
-Storage: Store diluted solutions at room temperature or under refrigeration according to the manufacturer's instructions.
Intermittent IV Infusion Administration
-Infuse IV over approximately 15 to 30 minutes.
Intermittent IV Push
Reconstitution
-Reconstitute the 500 mg and 1 g vials with 2 mL and 2.5 mL of Sterile Water for Injection to yield concentrations of 225 mg/mL and 330 mg/mL, respectively.
-Storage: Reconstituted solutions are stable for 24 hours at room temperature or for 10 days if stored under refrigeration (5 degrees C or 41 degrees F).
Dilution
-Further dilute the reconstituted solution with 5 to 10 mL of Sterile Water for Injection.
-A maximum concentration of 100 mg/mL is recommended for pediatric patients.
-Storage: Diluted solutions are stable for 24 hours at room temperature or for 10 days if stored under refrigeration (5 degrees C or 41 degrees F).
Intermittent IV Push Administration
-Administer slow IV push over at least 3 to 5 minutes.
-Doses have been administered over 2 to 5 minutes in adult studies.
Intramuscular Administration
Reconstitution
-Reconstitute the 500 mg and 1 g vials with 2 mL and 2.5 mL of Sterile Water for Injection to yield concentrations of 225 mg/mL and 330 mg/mL, respectively.
-Storage: Reconstituted solution is stable for 24 hours at room temperature or 10 days refrigerated.
Intramuscular Injection
-Inject deeply into a large muscle mass (e.g., anterolateral thigh or deltoid [children and adolescents only]).
Reports of increased BUN (azotemia) and serum creatinine concentrations, as well as renal failure (unspecified), have been received with cefazolin use. Acute tubulo-interstitial nephritis was reported in postmarketing experience with cefazolin. Renal impairment and toxic nephropathy have been reported for cephalosporin-class antibacterials.
Serious and occasionally fatal hypersensitivity reactions have been reported in patients receiving beta-lactam antibiotics. Anaphylaxis (anaphylactoid reactions), urticaria, pruritus, drug fever, rash, and Stevens-Johnson syndrome have been reported with cefazolin. Serum sickness-like reaction and acute generalized exanthematous pustulosis (AGEP) have been reported in postmarketing experience with cefazolin. Erythema multiforme and toxic epidermal necrolysis have been reported for cephalosporin-class antibacterials. If an allergic reaction occurs, discontinue cefazolin use.
Gastrointestinal adverse reactions such as diarrhea, oral ulceration, vomiting, nausea, stomach cramps, epigastric pain, pyrosis (heartburn), flatulence, and anorexia have been reported with cefazolin therapy. In pediatric surgical prophylaxis trials, nausea was reported in 14.8% of patients.
Neutropenia, leukopenia, thrombocythemia/thrombocytosis, and thrombocytopenia have been reported during cefazolin therapy. Additionally, eosinophilia has been noted and may be associated with a hypersensitivity reaction. Cephalosporins may be associated with a fall in prothrombin activity (hypoprothrombinemia). Risk factors include renal or hepatic impairment, poor nutritional state, prolonged antibiotics, and patients previously stabilized on anticoagulant therapy. Monitor prothrombin time in patients at risk and administer vitamin K as necessary. Positive direct Coombs' tests have been reported in patients receiving cephalosporins. If hematological testing is done in patients receiving cephalosporins, a positive Coombs' test should be considered as being possibly due to the antibiotic. Aplastic anemia, hemolytic anemia, pancytopenia, and bleeding have been reported for cephalosporin-class antibacterials.
An injection site reaction of phlebitis or induration has been reported with cefazolin. Pain at the site of intramuscular administration has occurred infrequently. In pediatric surgical prophylaxis trials, infusion site pain was reported in 6.6% of patients.
Dizziness, fainting, lightheadedness, confusion, weakness, tiredness, hypotension, somnolence (drowsiness), and headache have been reported with cefazolin. In pediatric surgical prophylaxis studies, headache was reported in 4.9% of patients. Seizures may occur with cefazolin use, particularly in patients with renal impairment when the dosage is not reduced appropriately. Discontinue cefazolin if seizures occur or make appropriate dosage adjustments in patients with renal impairment.
Transient elevated hepatic enzymes (SGOT, SGPT) and rise in alkaline phosphatase concentrations have been reported with cefazolin. Reports of hepatitis have been received. Hepatic impairment, including cholestasis, has been reported for cephalosporin-class antibacterials.
Microbial overgrowth and superinfection can occur with antibiotic use. C. difficile-associated diarrhea (CDAD) or pseudomembranous colitis has been reported with cefazolin. If pseudomembranous colitis is suspected or confirmed, ongoing antibacterial therapy not directed against C. difficile may need to be discontinued. Institute appropriate fluid and electrolyte management, protein supplementation, C. difficile-directed antibacterial therapy, and surgical evaluation as clinically appropriate. Oral candidiasis (thrush) as well as genital and anal pruritus (pruritus ani), including vulvar pruritus, genital and vaginal candidiasis, and vaginitis, have been reported with cefazolin.
Cefazolin is contraindicated in patients with cephalosporin hypersensitivity. Before starting therapy with cefazolin, inquire about previous hypersensitivity reactions to cefazolin, cephalosporins, penicillins, or other drugs. Use cefazolin with caution in patients with penicillin hypersensitivity because cross-hypersensitivity among beta-lactam antibiotics has been clearly documented and may occur in up to 10% of patients with a history of penicillin allergy. If an allergic reaction to cefazolin occurs, discontinue treatment with the drug. Serious acute hypersensitivity reactions may require treatment with epinephrine and other emergency measures, including oxygen, intravenous fluids, intravenous antihistamines, corticosteroids, vasopressors, and airway management, as clinically indicated. Hypersensitivity reactions, including anaphylaxis, have been reported with the administration of dextrose-containing products. These reactions have been reported in patients receiving high concentrations of dextrose (i.e., 50% dextrose). They have also been reported when corn-derived dextrose solutions were administered to patients with or without a history of corn hypersensitivity.
After an initial loading dose, a lower daily cefazolin dose is required for patients with low urinary output due to renal impairment (CrCl less than 55 mL/minute in adults and 70 mL/minute in pediatric patients) or renal failure. Seizures may occur with cefazolin use, particularly in patients with renal impairment when the dosage is not reduced appropriately. Discontinue cefazolin if seizures occur or make appropriate dosage adjustments in patients with renal impairment. Continue anticonvulsant therapy in patients with known seizure disorder.
Consider pseudomembranous colitis in patients presenting with diarrhea after antibacterial use. Careful medical history is necessary as pseudomembranous colitis has been reported to occur over 2 months after the administration of antibacterial agents. Almost all antibacterial agents, including cefazolin, have been associated with pseudomembranous colitis or C. difficile-associated diarrhea (CDAD) which may range in severity from mild to life-threatening. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.
Administration of cefazolin may result in laboratory test interference. Specifically, a false-positive reaction for glucose in the urine has been observed in patients receiving cephalosporins, such as cefazolin, and using glucose tests based on Benedict's copper reduction reaction that determine the amount of reducing substances like glucose in the urine. Diabetic patients who test their urine for glucose should use glucose tests based on enzymatic glucose oxidase reactions while on cefazolin treatment. Additionally, a positive direct Coombs test may develop in some patients. In hematologic studies or in transfusion cross-matching procedures when antiglobulin tests are performed on the minor side or in Coombs test of newborns whose mothers received cefazolin before delivery, clinicians should keep in mind that a positive Coombs test may be due to the drug. Cefazolin may also interfere with certain HPLC techniques and effect theophylline serum concentration measurements.
Many cephalosporins have been rarely associated with a fall in prothrombin activity (hypoprothrombinemia). Those at risk include patients with renal or hepatic impairment, or poor nutritional state, as well as patients receiving a protracted course of antimicrobial therapy. Prothrombin time should be monitored in patients at risk and exogenous vitamin K administered as indicated. Cephalosporins that contain the NMTT side chain (e.g., cefoperazone, cefamandole, cefotetan) have been particularly associated with an increased risk for bleeding. Cephalosporins should be used cautiously in patients with a preexisting coagulopathy (e.g., vitamin K deficiency), since these patients may be at a higher risk for these complications. Also, positive direct Coombs' tests have been reported in patients receiving cephalosporins, including cefazolin. In patients receiving cephalosporins and undergoing hematologic testing, a positive Coombs' test should be considered as possibly being caused by the antibiotic. If anemia develops during or after treatment with cefazolin, drug-induced hemolytic anemia should be considered.
No overall differences in safety or effectiveness of cefazolin were observed between the older adult and younger adults in clinical trials. Cefazolin is excreted renally; because geriatric patients are more likely to have decreased renal function, care should be taken in dose selection and it may be useful to monitor renal function. The federal Omnibus Budget Reconciliation Act (OBRA) regulates medication use in residents of long-term care facilities. According to OBRA, use of antibiotics should be limited to confirmed or suspected bacterial infections. Antibiotics are non-selective and may result in the eradication of beneficial microorganisms while promoting the emergence of undesired ones, causing secondary infections such as oral thrush, colitis, or vaginitis. Any antibiotic may cause diarrhea, nausea, vomiting, anorexia, and hypersensitivity reactions.
Use cefazolin for injection in dextrose with caution in patients with overt or known subclinical diabetes mellitus or carbohydrate intolerance for any reason. Also, patients with diabetes mellitus who test their urine for glucose should use glucose tests based on enzymatic glucose oxidase reactions while on cefazolin treatment. A false-positive reaction for glucose in the urine has been observed in patients receiving cephalosporins, such as cefazolin, and using glucose tests based on Benedict's copper reduction reaction that determine the amount of reducing substances like glucose in the urine.
While available studies cannot definitively establish the absence of risk, available data over several decades with cephalosporin use, including cefazolin, in human pregnancy have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. These studies have methodologic limitations, including small sample size, retrospective data collection, and inconsistent comparator groups. Cefazolin crosses the placenta. Animal reproduction studies with cefazolin during organogenesis at doses 1 to 3 times the maximum recommended human dose (MRHD) did not demonstrate adverse developmental outcomes.
Data from published literature report that cefazolin is present in human milk, but is not expected to accumulate in the breast-feeding infant. There are no data on the effects of cefazolin on the breast-fed child or on milk production. Previous American Academy of Pediatrics (AAP) recommendations considered cefazolin as generally compatible with breast-feeding.
Per the manufacturer, this drug has been shown to be active against most strains of the following microorganisms either in vitro and/or in clinical infections: Escherichia coli, Proteus mirabilis, Staphylococcus aureus (MSSA), Staphylococcus epidermidis, Streptococcus agalactiae (group B streptococci), Streptococcus pneumoniae, Streptococcus pyogenes (group A beta-hemolytic streptococci), Streptococcus sp.
NOTE: The safety and effectiveness in treating clinical infections due to organisms with in vitro data only have not been established in adequate and well-controlled clinical trials.
This drug may also have activity against the following microorganisms: Haemophilus influenzae (beta-lactamase negative), Klebsiella pneumoniae, Shigella sp.
NOTE: Some organisms may not have been adequately studied during clinical trials; therefore, exclusion from this list does not necessarily negate the drug's activity against the organism.
For the treatment of upper respiratory tract infections:
-for the treatment of mild upper respiratory tract infections:
Intravenous or Intramuscular dosage:
Adults: 250 to 500 mg IV or IM every 8 hours.
Infants, Children, and Adolescents: 25 to 50 mg/kg/day (Max: 1.5 g/day) IV or IM divided every 6 to 8 hours.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours.
-for the treatment of moderate to severe upper respiratory tract infections:
Intravenous or Intramuscular dosage:
Adults: 500 mg to 1 g IV or IM every 6 to 8 hours.
Infants, Children, and Adolescents: 25 to 100 mg/kg/day (Max: 4 g/day) IV or IM divided every 6 to 8 hours.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours.
For the treatment of urinary tract infection (UTI):
-for the treatment of acute, uncomplicated UTI:
Intravenous or Intramuscular dosage:
Adults: 1 g IV or IM every 12 hours.
Infants, Children, and Adolescents 2 months to 17 years: 25 to 50 mg/kg/day (Max: 2 g/day) IV or IM divided every 6 to 8 hours.
-for the treatment of moderate to severe UTI:
Intravenous or Intramuscular dosage:
Adults: 500 mg to 1 g IV or IM every 6 to 8 hours.
Infants, Children, and Adolescents 2 months to 17 years: 25 to 100 mg/kg/day (Max: 4 g/day) IV or IM divided every 6 to 8 hours.
Infants younger than 2 months: 25 to 100 mg/kg/day (Max: 4 g/day) IV or IM divided every 6 to 8 hours. Infants younger than 2 to 3 months are at risk for systemic infection and rapid change in their clinical condition. Treat UTIs as presumed pyelonephritis in these patients.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours. Neonates are at risk for systemic infection and rapid change in their clinical condition. Treat UTIs as presumed pyelonephritis in these patients.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours. Neonates are at risk for systemic infection and rapid change in their clinical condition. Treat UTIs as presumed pyelonephritis in these patients.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours. Neonates are at risk for systemic infection and rapid change in their clinical condition. Treat UTIs as presumed pyelonephritis in these patients.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours. Neonates are at risk for systemic infection and rapid change in their clinical condition. Treat UTIs as presumed pyelonephritis in these patients.
For the treatment of infective endocarditis:
-for the treatment of native valve endocarditis due to highly susceptible streptococci, including viridans group streptococci* as well as groups A, B*, C*, G*, and nonenterococcal group D* streptococci:
Intravenous or Intramuscular dosage:
Adults: Not recommended by guidelines. The FDA-approved dosage is 1 to 1.5 g IV or IM every 6 hours for group A beta-hemolytic streptococci. In rare instances, doses up to 12 g/day IV or IM have been used.
Infants, Children, and Adolescents: 100 mg/kg/day (Max: 12 g/day) IV or IM divided every 8 hours for 4 weeks.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours for 4 weeks.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours for 4 weeks.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours for 4 weeks.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours for 4 weeks.
-for the treatment of native valve endocarditis due to highly susceptible S. pneumoniae*:
Intravenous dosage:
Adults: 2 g IV every 8 hours for 4 weeks.
-for the treatment of prosthetic valve endocarditis due to highly susceptible S. pneumoniae*:
Intravenous dosage:
Adults: 2 g IV every 8 hours for 6 weeks.
-for the treatment of native valve endocarditis due to methicillin-susceptible S. aureus (MSSA):
Intravenous or Intramuscular dosage:
Adults: 2 g IV every 8 hours for 4 to 6 weeks. The FDA-approved dosage is 1 to 1.5 g IV or IM every 6 hours. In rare instances, doses up to 12 g/day IV or IM have been used.
Infants, Children, and Adolescents: 100 mg/kg/day (Max: 12 g/day) IV or IM divided every 8 hours for 4 to 6 weeks; consider the addition of gentamicin for 3 to 5 days.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours for 4 to 6 weeks; consider the addition of gentamicin for 3 to 5 days.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours for 4 to 6 weeks; consider the addition of gentamicin for 3 to 5 days.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours for 4 to 6 weeks; consider the addition of gentamicin for 3 to 5 days.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours for 4 to 6 weeks; consider the addition of gentamicin for 3 to 5 days.
-for the treatment of prosthetic valve endocarditis due to methicillin-susceptible S. aureus (MSSA):
Intravenous or Intramuscular dosage:
Adults: 2 g IV every 8 hours for at least 6 weeks plus rifampin for at least 6 weeks and gentamicin for 2 weeks. The FDA-approved dosage is 1 to 1.5 g IV or IM every 6 hours. In rare instances, doses up to 12 g/day IV or IM have been used.
Infants, Children, and Adolescents: 100 mg/kg/day (Max: 12 g/day) IV or IM divided every 8 hours for at least 6 weeks plus rifampin for at least 6 weeks and gentamicin for 2 weeks.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours for at least 6 weeks plus rifampin for at least 6 weeks and gentamicin for 2 weeks.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours for at least 6 weeks plus rifampin for at least 6 weeks and gentamicin for 2 weeks.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours for at least 6 weeks plus rifampin for at least 6 weeks and gentamicin for 2 weeks.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours for at least 6 weeks plus rifampin for at least 6 weeks and gentamicin for 2 weeks.
For bacterial endocarditis prophylaxis*:
Intravenous or Intramuscular dosage:
Adults: 1 g IV or IM as a single dose given 30 to 60 minutes before procedure.
Children and Adolescents: 50 mg/kg/dose (Max: 1 g/dose) IV or IM as a single dose given 30 to 60 minutes before procedure.
For surgical infection prophylaxis:
-for general surgical infection prophylaxis:
Intravenous or Intramuscular dosage:
Adults weighing 120 kg or more: 3 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing of 500 mg to 1 g IV/IM every 2 to 4 hours from the first preoperative dose. May continue 3 g IV every 6 to 8 hours for no more than 24 hours post-operatively if necessary. The FDA-approved post-operative dosage is 500 mg to 1 g IV/IM every 8 hours.
Adults weighing less than 120 kg: 1 g IV or IM or 2 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing of 500 mg to 1 g IV/IM every 2 to 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM or 2 g IV every 6 to 8 hours for no more than 24 hours post-operatively if necessary.
Children and Adolescents 10 to 17 years weighing 50 kg or more: 2 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing of 500 mg to 1 g IV/IM every 2 to 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary.
Children and Adolescents 10 to 17 years weighing less than 50 kg: 1 g IV or IM as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing of 500 mg to 1 g IV/IM every 2 to 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary.
Infants and Children 1 month to 9 years*: 30 mg/kg (Max: 2 g/dose) IV or IM as a single dose within 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 30 mg/kg (Max: 2 g/dose) IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary.
-for surgical infection prophylaxis for cardiothoracic procedures:
Intravenous or Intramuscular dosage:
Adults weighing 120 kg or more: 3 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing of 500 mg to 1 g IV/IM every 2 to 4 hours from the first preoperative dose. May continue 3 g IV every 6 to 8 hours for no more than 24 hours post-operatively if necessary. Where the occurrence of infection may be particularly devastating, prophylaxis may be continued for up to 3 to 5 days. However, a longer prophylaxis duration of 48 hours (or more) for certain cardiothoracic procedures is controversial. The FDA-approved post-operative dosage is 500 mg to 1 g IV/IM every 8 hours.
Adults weighing less than 120 kg: 1 g IV or IM or 2 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing of 500 mg to 1 g IV/IM every 2 to 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM or 2 g IV every 6 to 8 hours for no more than 24 hours post-operatively if necessary. Where the occurrence of infection may be particularly devastating, prophylaxis may be continued for up to 3 to 5 days. However, a longer prophylaxis duration of 48 hours (or more) for certain cardiothoracic procedures is controversial.
Children and Adolescents 10 to 17 years weighing 50 kg or more: 2 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing of 500 mg to 1 g IV/IM every 2 to 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary. Where the occurrence of infection may be particularly devastating, prophylaxis may be continued for up to 3 to 5 days. However, a longer prophylaxis duration of 48 hours (or more) for certain cardiothoracic procedures is controversial.
Children and Adolescents 10 to 17 years weighing less than 50 kg: 1 g IV or IM as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing of 500 mg to 1 g IV/IM every 2 to 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary. Where the occurrence of infection may be particularly devastating, prophylaxis may be continued for up to 3 to 5 days. However, a longer prophylaxis duration of 48 hours (or more) for certain cardiothoracic procedures is controversial.
Infants and Children 1 month to 9 years*: 30 mg/kg (Max: 2 g/dose) IV or IM as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 30 mg/kg (Max: 2 g/dose) IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary. A longer prophylaxis duration of 48 hours for certain cardiothoracic procedures is controversial.
-for ophthalmic surgical infection prophylaxis*:
Intraocular dosage:
Adults: 100 mg by subconjunctival injection or 1 to 2.5 mg by intracameral injection is optional at the end of the procedure. Perioperative antisepsis with povidone-iodine is recommended. The necessity of continuing topical antimicrobials postoperatively has not been established.
For perinatal Group B streptococcal infection prophylaxis* in persons allergic to penicillin:
Intravenous dosage:
Adults: 2 g IV loading dose at the time of labor or rupture of membranes, followed by 1 g IV every 8 hours until delivery. Cefazolin is recommended as an alternative for persons with a low-risk penicillin allergy. Antibiotics administered for at least 4 hours before delivery have been found to be highly effective at preventing the transmission of Group B Streptococcus.
Adolescents: 2 g IV loading dose at the time of labor or rupture of membranes, followed by 1 g IV every 8 hours until delivery. Cefazolin is recommended as an alternative for persons with a low-risk penicillin allergy. Antibiotics administered for at least 4 hours before delivery have been found to be highly effective at preventing the transmission of Group B Streptococcus.
For the treatment of prostatitis and epididymitis:
Intravenous or Intramuscular dosage:
Adults: 500 mg to 1 g IV or IM every 6 to 8 hours. The usual maximum dose is 6 g/day. Not recommended for the treatment of sexually transmitted epididymitis.
Infants, Children, and Adolescents: 25 to 100 mg/kg/day (Max: 6 g/day) IV or IM divided every 8 hours.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours.
For the treatment of lower respiratory tract infections (LRTIs), including pneumococcal pneumonia and community-acquired pneumonia (CAP):
-for the treatment of mild lower respiratory tract infections:
Intravenous or Intramuscular dosage:
Adults: 250 to 500 mg IV or IM every 8 hours.
Infants, Children, and Adolescents: 25 to 50 mg/kg/day (Max: 1.5 g/day) IV or IM divided every 6 to 8 hours.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours.
-for the treatment of moderate to severe lower respiratory tract infections:
Intravenous or Intramuscular dosage:
Adults: 500 mg to 1 g IV or IM every 6 to 8 hours.
Infants, Children, and Adolescents: 25 to 100 mg/kg/day (Max: 4 g/day) IV or IM divided every 6 to 8 hours.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours.
-for the treatment of severe, life-threatening lower respiratory tract infections:
Intravenous or Intramuscular dosage:
Adults: 1 to 1.5 g IV or IM every 6 hours. In rare instances, doses up to 12 g/day IV or IM have been used.
Infants, Children, and Adolescents: 100 mg/kg/day (Max: 6 g/day) IV or IM divided every 6 to 8 hours. In rare instances, doses up to 12 g/day IV or IM have been used.
-for the treatment of pneumococcal pneumonia:
Intravenous or Intramuscular dosage:
Adults: 500 mg IV or IM every 12 hours.
-for the treatment of community-acquired pneumonia (CAP) due methicillin-sensitive Staphylococcus aureus (MSSA):
Intravenous dosage:
Infants, Children, and Adolescents 4 months to 17 years: 150 mg/kg/day (Max: 6 g/day) IV divided every 8 hours for 10 days.
For the treatment of bacteremia:
Intravenous or Intramuscular dosage:
Adults: 2 g IV every 8 hours for S. aureus infections. The FDA-labeled dosage is 1 to 1.5 g IV or IM every 6 hours. In rare instances, doses up to 12 g/day IV or IM have been used.
Infants, Children, and Adolescents: 100 mg/kg/day (Max: 6 g/day) IV or IM divided every 8 hours. Guidelines recommend cefazolin for 7 to 14 days as a first-line treatment option for S. aureus bacteremia.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours. Guidelines recommend cefazolin for at least 14 days as a first-line treatment option for S. aureus bacteremia.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours. Guidelines recommend cefazolin for at least 14 days as a first-line treatment option for S. aureus bacteremia.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours. Guidelines recommend cefazolin for at least 14 days as a first-line treatment option for S. aureus bacteremia.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours. Guidelines recommend cefazolin for at least 14 days as a first-line treatment option for S. aureus bacteremia.
For the treatment of bone and joint infections, including osteomyelitis, infectious arthritis, infectious bursitis, and orthopedic device-related infection*:
-for the treatment of unspecified osteomyelitis:
Intravenous dosage:
Adults: 1 to 2 g IV every 8 hours for 4 to 6 weeks.
Infants, Children, and Adolescents 3 months to 17 years: 100 to 150 mg/kg/day (Max: 12 g/day) IV divided every 6 to 8 hours. Treat for 2 to 4 days or until clinically improved, followed by oral step-down therapy for a total duration of 3 to 4 weeks for uncomplicated cases. A longer course (i.e., 4 to 6 weeks or longer) may be needed for severe or complicated infections.
Infants 1 to 2 months: 100 to 150 mg/kg/day IV divided every 6 to 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
-for the treatment of native vertebral osteomyelitis:
Intravenous dosage:
Adults: 1 to 2 g IV every 8 hours for 6 weeks.
-for the treatment of infectious bursitis:
Intravenous dosage:
Adults: 1 to 2 g IV every 8 hours for 2 to 3 weeks. Generally, 2 weeks is appropriate for most patients; immunocompromised patients may require a longer duration.
Children and Adolescents: 100 to 150 mg/kg/day (Max: 12 g/day) IV divided every 6 to 8 hours for 2 to 3 weeks. Generally, 2 weeks is appropriate for most patients; immunocompromised patients may require a longer duration.
-for the treatment of infectious arthritis:
Intravenous dosage:
Adults: 1 to 2 g IV every 8 hours. Treat for 1 to 2 weeks or until clinically improved, followed by oral step-down therapy for 2 to 4 weeks.
Infants, Children, and Adolescents 3 months to 17 years: 100 to 150 mg/kg/day (Max: 12 g/day) IV divided every 6 to 8 hours. Treat for 2 to 4 days or until clinically improved, followed by oral step-down therapy for a total duration of 2 to 3 weeks for uncomplicated cases. A longer course (i.e., 4 to 6 weeks or longer) may be needed for septic hip arthritis or severe or complicated infections.
Infants 1 to 2 months: 100 to 150 mg/kg/day IV divided every 6 to 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
-for the treatment of prosthetic joint infections*:
Intravenous dosage:
Adults: 1 to 2 g IV every 8 hours in combination with rifampin for 2 to 6 weeks, followed by oral step-down therapy, which may be followed by long-term suppressive therapy.
For the treatment of mastitis:
Intravenous dosage:
Adults: 1 g IV every 8 hours for 10 to 14 days.
For the treatment of neonatal mastitis:
Intravenous dosage:
Infants 1 to 2 months: 25 to 75 mg/kg/day IV divided every 8 hours. Up to 100 mg/kg/day IV divided every 8 hours for severe infections.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV every 8 hours.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV every 12 hours.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV every 8 hours.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV every 12 hours.
For the treatment of intraabdominal infections, including peritonitis*, appendicitis*, intraabdominal abscess*, biliary tract infections (cholecystitis), and peritoneal dialysis-related peritonitis*:
-for the treatment of complicated community-acquired intraabdominal infections with adequate source control:
Intravenous or Intramuscular dosage:
Adults: 1 g IV or IM every 6 to 8 hours or 2 g IV every 8 hours as part of combination therapy for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.
Infants, Children, and Adolescents: 25 to 100 mg/kg/day (Max: 6 g/day) IV or IM divided every 8 hours as part of combination therapy for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours as part of combination therapy for 7 to 10 days.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours as part of combination therapy for 7 to 10 days.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours as part of combination therapy for 7 to 10 days.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours as part of combination therapy for 7 to 10 days.
-for the treatment of peritoneal dialysis-related peritonitis*:
Intermittent Intraperitoneal dosage*:
Adults: 15 to 20 mg/kg/dose intraperitoneally every 24 hours for 14 to 21 days.
Infants, Children, and Adolescents: 20 mg/kg/dose intraperitoneally every 24 hours for 14 to 21 days.
Continuous Intraperitoneal dosage*:
Adults: 500 mg/L intraperitoneal loading dose, followed by 125 mg/L in each dialysate exchange. Treat for 14 to 21 days.
Infants, Children, and Adolescents: 500 mg/L intraperitoneal loading dose, followed by 125 mg/L in each dialysate exchange. Treat for 14 to 21 days.
For the treatment of uncomplicated and complicated skin and skin structure infections, including cellulitis, erysipelas, skin abscesses, necrotizing infections, pyomyositis, and surgical incision site infections:
-for the treatment of mild skin and skin structure infections:
Intravenous or Intramuscular dosage:
Adults: 250 to 500 mg IV or IM every 8 hours.
Infants, Children, and Adolescents: 25 to 50 mg/kg/day (Max: 1.5 g/day) IV or IM divided every 6 to 8 hours.
-for the treatment of cellulitis and erysipelas due to methicillin-sensitive Staphylococcus aureus (MSSA):
Intravenous or Intramuscular dosage:
Adults: 1 g IV or IM every 8 hours for 5 to 14 days.
Infants, Children, and Adolescents: 50 mg/kg/day (Max: 3 g/day) IV or IM divided every 8 hours for 5 to 14 days.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours for 5 to 14 days.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours for 5 to 14 days.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours for 5 to 14 days.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours for 5 to 14 days.
-for the treatment of cellulitis and erysipelas due to Streptococcus sp.:
Intravenous or Intramuscular dosage:
Adults: 1 g IV or IM every 8 hours for 5 to 14 days.
Infants, Children, and Adolescents: 100 mg/kg/day (Max: 3 g/day) IV or IM divided every 8 hours for 5 to 14 days.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV or IM every 8 hours for 5 to 14 days.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV or IM every 12 hours for 5 to 14 days.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV or IM every 8 hours for 5 to 14 days.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV or IM every 12 hours for 5 to 14 days.
-for the treatment of purulent skin and soft tissue infections, including skin abscesses:
Intravenous dosage:
Adults: 1 g IV every 8 hours for 5 to 10 days plus incision and drainage.
Infants, Children, and Adolescents: 50 mg/kg/day (Max: 3 g/day) IV divided every 8 hours for 5 to 10 days plus incision and drainage.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV every 8 hours for 5 to 10 days plus incision and drainage.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV every 12 hours for 5 to 10 days plus incision and drainage.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV every 8 hours for 5 to 10 days plus incision and drainage.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV every 12 hours for 5 to 10 days plus incision and drainage.
-for the treatment of necrotizing infections of the skin, fascia, and muscle:
Intravenous dosage:
Adults: 1 g IV every 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.
Infants, Children, and Adolescents: 100 mg/kg/day (Max: 3 g/day) IV divided every 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV every 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV every 12 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.
Neonates younger than 32 weeks gestation and 8 days and older*: 25 mg/kg/dose IV every 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV every 12 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.
-for the treatment of pyomyositis:
Intravenous dosage:
Adults: 1 g IV every 8 hours for 14 to 21 days.
Infants, Children, and Adolescents: 50 mg/kg/day (Max: 3 g/day) IV divided every 8 hours for 14 to 21 days.
Neonates 32 weeks gestation and older and 8 days and older*: 50 mg/kg/dose IV every 8 hours for 14 to 21 days.
Neonates 32 weeks gestation and older and 0 to 7 days*: 50 mg/kg/dose IV every 12 hours for 14 to 21 days.
Neonates younger than 32 weeks gestation and 7 days and older*: 25 mg/kg/dose IV every 8 hours for 14 to 21 days.
Neonates younger than 32 weeks gestation and 0 to 6 days*: 25 mg/kg/dose IV every 12 hours for 14 to 21 days.
-for the treatment of surgical incision site infections:
Intravenous dosage:
Adults: 1 g IV every 8 hours for incisional surgical site infections of the trunk or extremity away from the axilla or perineum.
For bacterial infection prophylaxis after penetrating trauma*:
-for bacterial infection prophylaxis after penetrating central nervous system trauma*:
Intravenous dosage:
Adults weighing more than 160 kg: 3 g IV every 6 to 8 hours for 5 days or until CSF leak is closed, whichever is longer. Add metronidazole for penetrating spinal cord injury if abdominal cavity is involved and consider adding metronidazole for penetrating brain injury if gross contamination with organic debris.
Adults weighing 81 to 160 kg: 2 g IV every 6 to 8 hours for 5 days or until CSF leak is closed, whichever is longer. Add metronidazole for penetrating spinal cord injury if abdominal cavity is involved and consider adding metronidazole for penetrating brain injury if gross contamination with organic debris.
Adults weighting 80 kg or less: 1 g IV every 6 to 8 hours for 5 days or until CSF leak is closed, whichever is longer. Add metronidazole for penetrating spinal cord injury if abdominal cavity is involved and consider adding metronidazole for penetrating brain injury if gross contamination with organic debris.
Infants, Children, and Adolescents: 25 to 75 mg/kg/day (Max: 6 g/day) IV divided every 8 hours for 5 days or until CSF leak is closed, whichever is longer. Add metronidazole for penetrating spinal cord injury if abdominal cavity is involved and consider adding metronidazole for penetrating brain injury if gross contamination with organic debris.
-for bacterial infection prophylaxis after penetrating maxillofacial and neck trauma or chest trauma*:
Intravenous dosage:
Adults weighing more than 160 kg: 3 g IV every 6 to 8 hours for 1 day. Add metronidazole for penetrating chest trauma with esophageal disruption and continue for 1 day after definitive washout.
Adults weighing 81 to 160 kg: 2 g IV every 6 to 8 hours for 1 day. Add metronidazole for penetrating chest trauma with esophageal disruption and continue for 1 day after definitive washout.
Adults weighing 80 kg or less: 1 g IV every 6 to 8 hours for 1 day. Add metronidazole for penetrating chest trauma with esophageal disruption and continue for 1 day after definitive washout.
Infants, Children, and Adolescents: 25 to 75 mg/kg/day (Max: 6 g/day) IV divided every 8 hours. Add metronidazole for penetrating chest trauma with esophageal disruption and continue for 1 day after definitive washout.
-for bacterial infection prophylaxis after penetrating abdominal trauma*:
Intravenous dosage:
Adults weighing more than 160 kg: 3 g IV every 6 to 8 hours plus metronidazole for 1 day after definitive washout.
Adults weighing 81 to 160 kg: 2 g IV every 6 to 8 hours plus metronidazole for 1 day after definitive washout.
Adults weighing 80 kg or less: 1 g IV every 6 to 8 hours plus metronidazole for 1 day after definitive washout.
Infants, Children, and Adolescents: 25 to 75 mg/kg/day (Max: 6 g/day) IV divided every 8 hours plus metronidazole for 1 day after definitive washout.
-for bacterial infection prophylaxis after penetrating extremity trauma (including skin, soft tissue, and bone with or without open fractures)*:
Intravenous dosage:
Adults weighing more than 160 kg: 3 g IV every 6 to 8 hours for 1 to 3 days.
Adults weighing 81 to 160 kg: 2 g IV every 6 to 8 hours for 1 to 3 days.
Adults weighing 80 kg or less: 1 g IV every 6 to 8 hours for 1 to 3 days.
Infants, Children and Adolescents: 25 to 75 mg/kg/day (Max: 6 g/day) IV divided every 8 hours for 1 to 3 days.
For the treatment of chorioamnionitis* or intraamniotic infection*:
Intravenous dosage:
Adults: 2 g IV every 8 hours during the intrapartum period as part of alternative combination therapy. Give 1 additional dose after cesarean delivery; an additional dose is generally not needed after vaginal delivery. Other risk factors such as bacteremia or persistent postpartum fever may require additional therapy.
Adolescents: 2 g IV every 8 hours during the intrapartum period as part of alternative combination therapy. Give 1 additional dose after cesarean delivery; an additional dose is generally not needed after vaginal delivery. Other risk factors such as bacteremia or persistent postpartum fever may require additional therapy.
Maximum Dosage Limits:
-Adults
12 g/day IV/IM.
-Geriatric
12 g/day IV/IM.
-Adolescents
100 mg/kg/day (Max: 6 g/day) IV/IM for most indications; however, doses up to 150 mg/kg/day (Max: 12 g/day) IV have been used off-label.
-Children
100 mg/kg/day (Max: 6 g/day) IV/IM for most indications; however, doses up to 150 mg/kg/day (Max: 12 g/day) IV have been used off-label.
-Infants
100 mg/kg/day IV/IM for most indications; however, doses up to 150 mg/kg/day IV have been used off-label.
-Neonates
32 weeks gestation and older and 8 days and older: Safety and efficacy have not been established; however, doses up to 150 mg/kg/day IV/IM have been used off-label.
32 weeks gestation and older and 0 to 7 days: Safety and efficacy have not been established; however, doses up to 100 mg/kg/day IV/IM have been used off-label.
younger than 32 weeks gestation and 7 days and older: Safety and efficacy have not been established; however, doses up to 75 mg/kg/day IV/IM have been used off-label.
younger than 32 weeks gestation and 0 to 6 days: Safety and efficacy have not been established; however, doses up to 50 mg/kg/day IV/IM have been used off-label.
Patients with Hepatic Impairment Dosing
Specific guidelines for dosage adjustment in hepatic impairment are not available; it appears that no dosage adjustments are needed.
Patients with Renal Impairment Dosing
Adult patients (FDA-approved labeling)
CrCl more than 54 mL/minute: No dosage adjustment needed.
CrCl 35 to 54 mL/minute: Administer every 8 hours or longer.
CrCl 11 to 34 mL/minute: After a normal loading dose, reduce maintenance dose by 50% and administer every 12 hours.
CrCl 10 mL/minute or less: After a normal loading dose, reduce the recommended dose by 50% and administer every 18 to 24 hours.
Adult patients (alternative)*
CrCl more than 50 mL/minute: No dosage adjustment needed.
CrCl 10 to 50 mL/minute: Administer the usual dose every 12 hours.
CrCl less than 10 mL/minute: Reduce the recommended dose by 50% and administer every 24 to 48 hours.
Pediatric patients (FDA-approved labeling)
CrCl more than 70 mL/minute: No dosage adjustment needed.
CrCl 40 to 70 mL/minute: After a normal loading dose, administer 60% of the normal daily dose divided every 12 hours.
CrCl 20 to 39 mL/minute: After a normal loading dose, administer 25% of the normal daily dose divided every 12 hours.
CrCl 5 to 19 mL/minute: After a normal loading dose, administer 10% of the normal daily dose divided every 24 hours.
Pediatric patients (alternative)*
The following dose adjustments are based on a usual pediatric dose of 50 to 100 mg/kg/day IV divided every 8 hours:
GFR 30 mL/minute/1.73m2 or more: No dosage adjustment needed.
GFR 10 to 29 mL/minute/1.73m2: 25 mg/kg/dose (Max: 2 g/dose) IV every 12 hours.
GFR less than 10 mL/minute/1.73m2: 25 mg/kg/dose (Max: 2 g/dose) IV every 24 hours.
Intermittent hemodialysis*
Adult patients
500 mg to 1 g IV every 24 hours; administer after hemodialysis on dialysis days. Alternatively, administer 1 to 2 IV every 48 to 72 hours after hemodialysis. Other recommendations suggest 15 to 20 mg/kg IV after hemodialysis.
Pediatric patients
25 mg/kg/dose (Max: 2 g/dose) IV every 24 hours.
Peritoneal dialysis*
Adult patients
500 mg IV every 12 hours.
Pediatric patients
25 mg/kg/dose (Max: 2 g/dose) IV every 24 hours.
Continuous renal replacement therapy (CRRT)*
NOTE: Various CRRT modalities include continuous venovenous hemofiltration (CVVH), continuous venovenous hemodialysis (CVVHD), continuous venovenous hemodiafiltration (CVVHDF), continuous venovenous high-flux hemodialysis (CVVHFD), continuous arteriovenous hemofiltration (CAVH), continuous arteriovenous hemodialysis (CAVHD), and continuous arteriovenous hemodiafiltration (CAVHDF). Dosing should take into consideration patient-specific factors (e.g., intrinsic renal function), type of infection, the duration of renal replacement therapy, the effluent flow rate, and the replacement solution administered.
Adult patients
Administering the usual dose every 12 hours has generally been suggested for CRRT. More specifically, consider a 2 g IV loading dose, then 1 to 2 g IV every 12 hours for CVVH and a 2 g IV loading dose, then 1 g IV every 8 hours or 2 g IV every 12 hours for CVVHD or CVVHDF.
Pediatric patients
25 mg/kg/dose (Max: 2 g/dose) IV every 8 hours.
*non-FDA-approved indication
Bumetanide: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Clofarabine: (Moderate) Concomitant use of clofarabine, a substrate of OAT1 and OAT3, and cefazolin, an inhibitor of OAT1 and OAT3, may result in increased clofarabine levels. Therefore, monitor for signs of clofarabine toxicity such as gastrointestinal toxicity (e.g., nausea, vomiting, diarrhea, mucosal inflammation), hematologic toxicity, and skin toxicity (e.g., hand and foot syndrome, rash, pruritus) in patients also receiving OAT1 and OAT3 inhibitors.
Desogestrel; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Dienogest; Estradiol valerate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Drospirenone: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Drospirenone; Estetrol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Drospirenone; Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Drospirenone; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Drospirenone; Ethinyl Estradiol; Levomefolate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Elagolix; Estradiol; Norethindrone acetate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Estradiol; Levonorgestrel: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Estradiol; Norethindrone: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Estradiol; Norgestimate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Ethacrynic Acid: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Ethinyl Estradiol; Norelgestromin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Ethinyl Estradiol; Norethindrone Acetate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Ethinyl Estradiol; Norgestrel: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Ethynodiol Diacetate; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Etonogestrel; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Furosemide: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Isoniazid, INH; Pyrazinamide, PZA; rifAMPin: (Moderate) Avoid coadministration of rifampin and cefazolin in patients at increased risk of bleeding. If no alternative treatment options are available, closely monitor prothrombin time and other coagulation tests, and administer vitamin K as indicated. Postmarketing reports suggest that concomitant administration of high doses of rifampin and cefazolin may prolong the prothrombin time, leading to severe vitamin K-dependent coagulation disorders that may be life-threatening or fatal.
Isoniazid, INH; rifAMPin: (Moderate) Avoid coadministration of rifampin and cefazolin in patients at increased risk of bleeding. If no alternative treatment options are available, closely monitor prothrombin time and other coagulation tests, and administer vitamin K as indicated. Postmarketing reports suggest that concomitant administration of high doses of rifampin and cefazolin may prolong the prothrombin time, leading to severe vitamin K-dependent coagulation disorders that may be life-threatening or fatal.
Leuprolide; Norethindrone: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Levonorgestrel: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Levonorgestrel; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Levonorgestrel; Ethinyl Estradiol; Ferrous Bisglycinate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Levonorgestrel; Ethinyl Estradiol; Ferrous Fumarate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Loop diuretics: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Norethindrone Acetate; Ethinyl Estradiol; Ferrous fumarate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Norethindrone: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Norethindrone; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Norethindrone; Ethinyl Estradiol; Ferrous fumarate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Norgestimate; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Norgestrel: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Oral Contraceptives: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Relugolix; Estradiol; Norethindrone acetate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
rifAMPin: (Moderate) Avoid coadministration of rifampin and cefazolin in patients at increased risk of bleeding. If no alternative treatment options are available, closely monitor prothrombin time and other coagulation tests, and administer vitamin K as indicated. Postmarketing reports suggest that concomitant administration of high doses of rifampin and cefazolin may prolong the prothrombin time, leading to severe vitamin K-dependent coagulation disorders that may be life-threatening or fatal.
Segesterone Acetate; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Sodium picosulfate; Magnesium oxide; Anhydrous citric acid: (Major) Prior or concomitant use of antibiotics with sodium picosulfate; magnesium oxide; anhydrous citric acid may reduce efficacy of the bowel preparation as conversion of sodium picosulfate to its active metabolite bis-(p-hydroxy-phenyl)-pyridyl-2-methane (BHPM) is mediated by colonic bacteria. If possible, avoid coadministration. Certain antibiotics (i.e., tetracyclines and quinolones) may chelate with the magnesium in sodium picosulfate; magnesium oxide; anhydrous citric acid solution. Therefore, these antibiotics should be taken at least 2 hours before and not less than 6 hours after the administration of sodium picosulfate; magnesium oxide; anhydrous citric acid solution.
Torsemide: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Warfarin: (Moderate) The concomitant use of warfarin with many classes of antibiotics, including cephalosporins, may increase the INR thereby potentiating the risk for bleeding. Inhibition of vitamin K synthesis due to alterations in the intestinal flora may be a mechanism; however, concurrent infection is also a potential risk factor for elevated INR. Additionally, certain cephalosporins (cefotetan, cefoperazone, cefamandole) are associated with prolongation of the prothrombin time due to the methylthiotetrazole (MTT) side chain at the R2 position, which disturbs the synthesis of vitamin K-dependent clotting factors in the liver. Monitor patients for signs and symptoms of bleeding. Additionally, increased monitoring of the INR, especially during initiation and upon discontinuation of the antibiotic, may be necessary.
Cefazolin, a beta-lactam antibiotic similar to penicillins, inhibits the third and final stage of bacterial cell wall synthesis by preferentially binding to specific penicillin-binding proteins (PBPs) that are located inside the bacterial cell wall. Penicillin-binding proteins are responsible for several steps in the synthesis of the cell wall and are found in quantities of several hundred to several thousand molecules per bacterial cell. Penicillin-binding proteins vary among different bacterial species. Thus, the intrinsic activity of cefazolin as well as other cephalosporins and penicillins against a particular organism depends on their ability to gain access to and bind with the necessary PBP. Like all beta-lactam antibiotics, cefazolin's ability to interfere with PBP-mediated cell wall synthesis ultimately leads to cell lysis. Lysis is mediated by bacterial cell wall autolytic enzymes (i.e., autolysins). The relationship between PBPs and autolysins is unclear, but it is possible that the beta-lactam antibiotic interferes with an autolysin inhibitor.
Beta-lactams, including cefazolin, exhibit concentration-independent or time-dependent killing. In vitro and in vivo animal studies have demonstrated that the major pharmacodynamic parameter that determines efficacy for beta-lactams is the amount of time free (non-protein bound) drug concentrations exceed the minimum inhibitory concentration (MIC) of the organism (free T above the MIC). This microbiological killing pattern is due to the mechanism of action, which is acylation of PBPs. There is a maximum proportion of PBPs that can be acylated; therefore, once maximum acylation has occurred, killing rates cannot increase. Free beta-lactam concentrations do not have to remain above the MIC for the entire dosing interval. The percentage of time required for both bacteriostatic and maximal bactericidal activity is different for the various classes of beta-lactams. Cephalosporins require free drug concentrations to be above the MIC for 35% to 40% of the dosing interval for bacteriostatic activity and 60% to 70% of the dosing interval for bactericidal activity.
The susceptibility interpretive criteria for cefazolin are delineated by pathogen. The MICs are defined for Enterobacterales as susceptible at 2 or less mcg/mL or less, intermediate at 4 mcg/mL, and resistant at 8 mcg/mL or more for infections other than uncomplicated urinary tract infections (UTIs) due to E. coli, K. pneumoniae, and P. mirabilis (based on a dosage regimen of 2 g IV every 8 hours) and susceptible at 16 mcg/mL or less and resistant at 32 mcg/mL or more for uncomplicated UTIs due to E. coli, K. pneumoniae, and P. mirabilis (based on a dosage regimen of 1 g IV every 12 hours); however, the FDA does not recognize separate susceptibility test interpretive criteria for uncomplicated UTIs. The MICs are defined for Vibrio sp. (excluding V. cholerae) as susceptible at 2 or less mcg/mL or less, intermediate at 4 mcg/mL, and resistant at 8 mcg/mL or more (based on a dosage regimen of 2 g IV every 8 hours). Penicillin-susceptible beta-hemolytic streptococci and methicillin-susceptible staphylococci can be considered susceptible to cefazolin.
The predominant mechanisms of resistance include the presence of extended-spectrum beta-lactamases and enzymatic hydrolysis.
Cefazolin is administered intravenously and intramuscularly. Approximately 80% of circulating drug is protein-bound. It is widely distributed into most body tissues and fluids; however, cefazolin does not reach therapeutic concentrations within the CSF. The drug concentrates in the urine at concentrations much higher than peak serum concentrations. The Vd in healthy adults after a single 2 g IV dose was 11.5 L. The Vd in healthy adults weighing 120 kg or more after a single 3 g IV dose was 17 L. Bile concentrations in patients without obstructive biliary disease can reach or exceed serum concentrations by up to 5 times; however, in patients with obstructive biliary disease, bile concentrations of cefazolin are considerably lower than serum concentrations (less than 1 mcg/mL). In synovial fluid, the cefazolin concentration becomes comparable to that reached in the serum at about 4 hours after drug administration. Cefazolin is not hepatically metabolized. Cefazolin is largely excreted unchanged into the urine with approximately 60% excreted within the first 6 hours, reaching 70% to 80% within the first 24 hours. In non-neonatal patients, including adults, with normal renal function, the elimination half-life is approximately 2 hours.
Affected cytochrome P450 isoenzymes and drug transporters: none
-Route-Specific Pharmacokinetics
Intravenous Route
Studies have shown that after IV administration of cefazolin to normal adult volunteers, mean serum concentrations peaked at 185 mcg/mL and were approximately 4 mcg/mL at 8 hours after a 1 g dose. After a single 2 g dose, the mean Tmax was 0.25 hours and mean Cmax was 280.9 mcg/mL. The AUC was 509.9 mcg x hour/mL. In a study of constant IV infusion of 3.5 mg/kg for 1 hour and 1.5 mg/kg for the next 2 hours in healthy volunteers, serum concentrations at the third hour were approximately 28 mcg/mL. In healthy adult subjects weighing 120 kg or more after a single 3 g IV dose, the mean Tmax was 0.55 hours and mean Cmax was 233 mcg/mL. The AUC was 585 mcg x hour/mL. Studies in hospitalized patients with infections indicate that cefazolin mean peak serum concentrations were approximately equivalent to those seen in healthy volunteers. When given as a slow IV push over 2 to 3 minutes, peak concentrations are achieved approximately 15 minutes after administration.
Intramuscular Route
Peak serum concentrations of cefazolin occur within 1 hour after an intramuscular (IM) dose. After IM administration of cefazolin to normal adult volunteers, the mean serum concentrations were 37 mcg/mL at 1 hour after a 500 mg dose, and 64 mcg/mL at 1 hour after a 1 g dose.
-Special Populations
Renal Impairment
Cefazolin is moderately dialyzable with 20% to 50% of the dose removed by dialysis. Data are unavailable in pediatric patients with renal impairment; however, in a pharmacokinetic study (n = 17) in adults with different degrees of renal function, elimination half-life of cefazolin was prolonged to approximately 10 hours in patients with a CrCl of 20 mL/minute and ranged from 15 to 45 hours in patients with a CrCl less than 5 mL/minute.
In patients undergoing peritoneal dialysis (2 L/hour), cefazolin produced mean serum concentrations of approximately 10 and 30 mcg/mL after 24 hours intraperitoneal instillation of a dialyzing solution containing 50 mg/L and 150 mg/L, respectively. Mean peak concentrations were 29 mcg/mL (range 13 to 44 mcg/mL) with 50 mg/L (n = 3), and 72 mcg/mL (range 26 to 142 mcg/mL) with 150 mg/L (n = 6). Intraperitoneal administration is usually well tolerated.
Pediatrics
Infants and Children
A simulation based on pharmacokinetic data from healthy adults (n = 24) and pediatric patients aged 10 to 17 years (n = 26) and 10 to 12 years (n = 12) indicates that the administration of cefazolin 1 g for pediatric patients weighing less than 50 kg and 2 g for those weighing 50 kg or more will provide comparable exposures between pediatric patients aged 10 to 17 years and healthy adults receiving cefazolin 2 g. In a pharmacokinetic study of infants and children (n = 9; 0.8 to 10 years) undergoing gastrointestinal surgery, mean clearance and elimination half-life values after a single IV cefazolin dose (15 to 26 mg/kg) were 1.4 mL/kg/minute and 1.7 hours, respectively.
Neonates
Protein binding in neonatal patients is highly variable; a study in neonates 2 to 28 days found the unbound fraction to be 0.22 to 0.83. The half-life of cefazolin in neonates is approximately 3 to 5 hours.