PHENYTOIN (Generic for DILANTIN)

Phenytoin 50mg, Chewable tablet

Alcohol

· Severity: Major

· Notes for Consumers: Do not drink alcohol while taking this medication. Drinking alcohol may alter the effects of your medication. Serious side effects may occur. Contact your care team if you experience new or worsening side effects.

· Notes for Professionals: Phenytoin theoretically can add to the CNS-depressant effects of alcohol. Chronic ingestion of alcohol induces hepatic microsomal isozymes and increases the clearance of phenytoin. Alcohol also exhibits epileptogenic potential. Alcohol should generally be avoided in patients on fosphenytoin or phenytoin. Acute ingestion of small amounts of ethanol in non-alcoholic patients does not appear to affect the hepatic metabolism of phenytoin to a clinically significant degree.

Phenytoin 50mg, Chewable tablet

Caffeine-containing Foods/Beverages

· Severity: Moderate

· Notes for Consumers: Hydantoins may decrease the actions of Caffeine; if you have a high intake of caffeinated foods or beverages you may experience a headache or irritability from decreased caffeine levels while taking these drugs until your body adjusts. If you take Caffeine for other purposes, notify your health care provider if you think Caffeine is not working as well for you.

· Notes for Professionals: Higher caffeine doses may be needed after hydantoin administration; hydantoins increase caffeine elimination.

Phenytoin 50mg, Chewable tablet

Cannabis

· Severity: Major

· Notes for Consumers: Discuss cannabis use with your care team. The effects of cannabis may be altered if used with your medication.

· Notes for Professionals: Advise patients to avoid cannabis use during phenytoin/fosphenytoin treatment. Concomitant use may decrease the concentration of some cannabinoids and alter their effects. The cannabinoids delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are CYP3A substrates and phenytoin/fosphenytoin are strong CYP3A inducers. Concomitant use of a cannabinoid product containing THC and CBD at an approximate 1:1 ratio with another strong CYP3A inducer decreased THC, 11-OH-THC, and CBD peak exposures by 36%, 87%, and 52% respectively.

Phenytoin 50mg, Chewable tablet

Enteral Feedings

· Severity: Major

· Notes for Consumers: Enteral feedings may decrease the effectiveness of Phenytoin suspension, by decreasing its absorption from the stomach. Take Phenytoin suspension 1 to 2 hours before or 1 to 2 hours after you take enteral feedings to limit an interaction. Phenytoin capsules do not appear to be affected by this interaction. If you are being treated for a seizure disorder, contact your health care provider if you notice an increase in the number or severity of seizures.

· Notes for Professionals: The oral absorption of phenytoin suspension can be substantially reduced (up to 70%) by the concurrent administration of enteral feedings. Conversely, when enteral feedings are halted, phenytoin concentrations may markedly rise. Other oral dosage forms of phenytoin (e.g., phenytoin sodium) do not interact with enteral feedings to the same extent as the oral suspension. There are several ways to manage patients receiving enteral feedings and phenytoin. If the patient is on intermittent feedings, time phenytoin administration 1 to 2 hours after the feeding, flush the tubing with water or normal saline, and delay subsequent feedings for another 1 to 2 hours. If practical, continuous feedings may be held for 1 to 2 hours before and after each phenytoin dose (again, flushing the tubing after drug administration); to minimize the amount of time feedings are held, give phenytoin suspension twice daily rather than more often. If enteral feeding cannot be held, increase the dose of phenytoin suspension to account for the interaction or consider the use of parenteral phenytoin/fosphenytoin. If larger enteral doses are used, phenytoin dosage reduction may be required when enteral nutrition is stopped, and an oral diet resumed. Regardless of the approach, monitor serum phenytoin concentrations and clinical status, adjusting the dosage to achieve desired therapeutic outcomes.

<b>DISCLAIMER:</b><em> This drug information content is provided for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Patients should always consult their physician with any questions regarding a medical condition and to obtain medical advice and treatment. Drug information is sourced from GSDD (Gold Standard Drug Database ) provided by Elsevier.</em>