Do not take this medicine with any of the following medications:
-delavirdine
-ibrutinib
-ranolazine

This medicine may also interact with the following medications:
-albendazole
-alcohol
-antiviral medicines for HIV or AIDS
-aspirin and aspirin-like medicines
-certain medicines for blood pressure like nifedipine, nimodipine, and verapamil
-certain medicines for cancer
-certain medicines for cholesterol like atorvastatin, simvastatin, and fluvastatin
-certain medicines for depression, anxiety, or psychotic disturbances
-certain medicines for fungal infections like ketoconazole and itraconazole
-certain medicines for irregular heart beat like amiodarone and quinidine
-certain medicines for seizures like carbamazepine, phenobarbital, and topiramate
-certain medicines for stomach problems like cimetidine and omeprazole
-chloramphenicol
-cyclosporine
-diazoxide
-digoxin
-disulfiram
-doxycycline
-female hormones, like estrogens and birth control pills
-furosemide
-halothane
-isoniazid
-medicines that relax muscles for surgery
-methylphenidate
-narcotic medicines for pain
-phenothiazines like chlorpromazine, mesoridazine, prochlorperazine, thioridazine
-praziquantel
-reserpine
-rifampin
-St. John''s Wort
-steroid medicines like prednisone or cortisone
-sulfonamides like sulfamethoxazole or sulfasalazine
-supplements like folic acid or vitamin D
-theophylline
-ticlopidine
-tolbutamide
-warfarin

They need to know if you have any of these conditions:
-an alcohol abuse problem
-Asian ancestry
-blood disorders or disease
-diabetes
-heart problems
-kidney disease
-liver disease
-porphyria
-receiving radiation therapy
-suicidal thoughts, plans, or attempt; a previous suicide attempt by you or a family member
-thyroid disease
-an unusual or allergic reaction to phenytoin, other medicines, foods, dyes, or preservatives
-pregnant or trying to get pregnant
-breast-feeding

Visit your doctor or health care provider for regular checks on your progress. This medicine needs careful monitoring. Your doctor or health care provider may schedule regular blood tests.

This medicine may cause serious skin reactions. They can happen weeks to months after starting the medicine. Contact your health care provider right away if you notice fevers or flu-like symptoms with a rash. The rash may be red or purple and then turn into blisters or peeling of the skin. Or, you might notice a red rash with swelling of the face, lips or lymph nodes in your neck or under your arms.

Wear a medical ID bracelet or chain, and carry a card that describes your disease and details of your medicine and dosage times.

Do not change brands or dosage forms of this medicine without discussing the change with your doctor or health care provider.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.

Birth control pills may not work properly while you are taking this medicine. Talk to your doctor about using an extra method of birth control.

This medicine can cause unusual growth of gum tissues. Visit your dentist regularly. Problems can arise if you need dental work, and in the day to day care of your teeth. Try to avoid damage to your teeth and gums when you brush or floss your teeth.

Do not take antacids at the same time as this medicine. If you get an upset stomach and want to take an antacid or medicine for diarrhea, make sure there is an interval of 2 to 3 hours before or after you took your phenytoin.

The use of this medicine may increase the chance of suicidal thoughts or actions. Pay special attention to how you are responding while on this medicine. Any worsening of mood, or thoughts of suicide or dying should be reported to your health care provider right away.

Women who become pregnant while using this medicine may enroll in the North American Antiepileptic Drug Pregnancy Registry by calling 1-888-233-2334. This registry collects information about the safety of antiepileptic drug use during pregnancy.

This medicine may cause a decrease in vitamin D and folic acid. You should make sure that you get enough vitamins while you are taking this medicine. Discuss the foods you eat and the vitamins you take with your health care provider.

Keep out of the reach of children.

Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Protect from light and moisture. Throw away any unused medicine after the expiration date.