Phenytoin Oral

In Depth

Generic Name: PHENYTOIN CHEWABLE TABLET - ORAL
Pronounced: (fen-eh-TOE-in, FEN-eh-toyn)

Phenytoin Oral Interactions

Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.

See also How to Use section.

This drug should not be used with the following medications because very serious interactions may occur:

azapropazone
darunavir
delavirdine
dofetilide
etravirine
nisoldipine
telithromycin

If you are currently using any of these medications, tell your doctor or pharmacist before starting phenytoin.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of:

colesevelam
molindone
pyridoxine (vitamin B6)
sucralfate
sulfa drugs
drugs affecting liver enzymes that remove phenytoin from your body (such as amiodarone, azole antifungals including itraconazole, cimetidine, ciprofloxacin, macrolide antibiotics including erythromycin, estrogens, isoniazid, rifamycins including rifabutin, St. John's wort, other anti-seizure medicines including carbamazepine/phenobarbital/valproic acid)

Phenytoin can speed up the removal of many other drugs from your body by affecting certain liver enzymes. This can affect how well these other drugs work. These other drugs include: some drugs to treat cancer (e.g., imatinib, irinotecan), corticosteroids (e.g., prednisone), cyclosporine, felodipine, quetiapine, quinidine, theophylline, vitamin D, warfarin. This is not a complete list. Tell your doctor or pharmacist of all other drugs you take.

Also report the use of drugs which might increase seizure risk (decrease seizure threshold) such as: phenothiazines (e.g., thioridazine) or tricyclic antidepressants (e.g., amitriptyline), among others. Consult your doctor or pharmacist for details.

Phenytoin may decrease the effectiveness of birth control pills, patches, implants or injections. This can result in pregnancy. You may need to use an additional form of reliable birth control while using this medication. Consult your doctor or pharmacist for details.

This product can affect the results of certain lab tests. Make sure laboratory personnel and your doctors know you use this drug.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.