PRECAUTIONS: Tell your doctor if you have: blood disorders (e.g., porphyria), allergies (especially drug allergies), lung problems, heart disease (including slow heart rate or heart blocks), liver disease. Use caution operating machinery or performing tasks requiring alertness. Limit alcohol use as it may increase the drowsiness effect of this medication. Limit your caffeine usage. Phenytoin is not recommended for use during pregnancy. Consult your doctor for details. This drug passes into breast milk. While there have been no reports of harm to a nursing infant, consult your doctor before breast-feeding.

DRUG INTERACTIONS: Inform your doctor about all the medicine you use (both prescription and nonprescription) especially if you take: "blood thinners" (warfarin), cimetidine, omeprazole, sucralfate, disulfiram, oral antifungal medication (azoles), xanthine drugs to treat asthma (theophylline), isoniazid, folic acid, pyrimethamine, sulfa antibiotics, rifamycins (e.g., rifabutin, rifampin), trimethoprim, amiodarone, fluoxetine, anti-cancer drugs, valproic acid, divalproex, estrogens, disopyramide, levodopa (Sinemet), digoxin, felodipine, primidone, felbamate, narcotic pain medicines (e.g., codeine), St John's wort, capecitabine. This drug may interfere with the effectiveness of birth control pills. Discuss using other methods of birth control with your doctor. Do not start or stop any medicine without doctor or pharmacist approval.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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