Phenytoin capsules and extended-release capsules

What is this medicine?

PHENYTOIN (FEN i toyn) is used to control seizures in certain types of epilepsy. It is also used to prevent seizures during or after surgery.

How should I use this medicine?

Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. If you are taking extended-release capsules, swallow them whole. Do not crush or chew. Take this medicine with food if it upsets your stomach. It may be best to take your medicine consistently with or without food. Take your doses at regular intervals. Do not take your medicine more often than directed. Do not stop taking this medicine suddenly. This increases the risk of seizures. Your doctor will tell you how much medicine to take. If your doctor wants you to stop the medicine, the dose will be slowly lowered over time to avoid any side effects.

Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:

• allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue

• breathing problems

• changes in vision

• chest pain or tightness

• confusion

• dark yellow or brown urine

• fast or irregular heartbeat

• fever, sore throat

• headache

• loss of seizure control

• poor control of body movements or difficulty walking

• redness, blistering, peeling or loosening of the skin, including inside the mouth

• unusual bleeding or bruising, pinpoint red spots on skin

• vomiting

• worsening of mood, thoughts or actions of suicide or dying

• yellowing of the eyes or skin

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

• constipation

• difficulty sleeping

• excessive hair growth on the face or body

• nausea

What may interact with this medicine?

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

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

Where should I keep my medicine?

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.

What should I tell my health care provider before I take this medicine?

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

What should I watch for while using this medicine?

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

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 professional.

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 professional 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.