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Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.





This medication is used to treat seizure disorders (epilepsy). It may be used with other seizure medications as determined by your doctor.

How To Use

Take this medication by mouth usually once or twice daily; or take as directed by your doctor. It may be taken with or without food. The dosage is based on your medical condition and response to therapy. It may be slowly adjusted over several weeks to improve seizure control. Drink plenty of water (6 to 8 glasses a day) while taking this medication. This may decrease the rare chance of developing kidney stones. Do not crush or chew the capsules. Swallow the capsule(s) whole. Do not stop taking this drug suddenly without your doctor's approval since seizures may reoccur.

Side Effects

Drowsiness, weight loss, constipation, dry mouth, dizziness, headache, nausea, vomiting, heartburn, diarrhea, restlessness, trouble sleeping, or irritability may occur. If any of these effects persist or worsen, notify your doctor. Tell your doctor immediately if any of these serious side effects occur: stomach pain, loss of coordination, mental/mood changes, slow reactions, vision changes, trouble speaking. Tell your doctor immediately if any of these unlikely but serious side effects occur: rash, lower back pain, pain when urinating, bloody urine, increase in seizures. Tell your doctor immediately if any of these highly unlikely but very serious side effects occur: persistent sore throat or fever, easy bruising or bleeding, mouth sores, yellowing eyes or skin, dark urine, decreased sweating or a rise in body temperature (especially in children under 17 years old). An allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of an allergic reaction include: rash, itching, swelling, dizziness, trouble breathing. If you notice other effects not listed above, contact your doctor or pharmacist.


Tell your doctor your medical history, especially of: kidney problems, liver problems, allergies (especially to sulfa drugs/sulfonamides). This drug may make you dizzy or drowsy; use caution engaging in activities requiring alertness such as driving or using machinery. Limit alcoholic beverages. This medication can cause decreased sweating. Avoid becoming overheated in hot weather, saunas, or during exercise or other activity since heatstroke may occur, especially in children. This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. It is not known whether this drug passes into breast milk. Due to the potential risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast- feeding.

Drug Interactions

Tell your doctor of all prescription and nonprescription medication you may use, especially of: other anti- seizure medication (e.g., carbamazepine, phenobarbital, phenytoin), corticosteroids (e.g., prednisone), rifampin, St John's wort, azole antifungals (e.g., itraconazole, ketoconazole), HIV medications (e.g., indinavir, ritonavir), amiodarone, cimetidine, macrolide antibiotics (e.g., clarithromycin, erythromycin), nefazodone. Also report use of drugs that cause drowsiness such as: medicine for sleep, sedatives, tranquilizers, anti-anxiety drugs (e.g., diazepam), narcotic pain relievers (e.g., codeine), psychiatric medicines (e.g., phenothiazines or tricyclics), muscle relaxants, antihistamines that cause drowsiness (e.g., diphenhydramine), anticholinergics (e.g., benztropine, hyoscyamine), acetazolamide, methazolamide. Check the labels on all your medicines (e.g., cough-and-cold products) because they may contain drowsiness-causing ingredients. Ask your pharmacist about the safe use of those products. Do not eat grapefruit or drink grapefruit juice unless your doctor instructs you otherwise. Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include slow heart beat, weakness, fatigue, dizziness, or difficulty breathing.


It is recommended you wear or carry identification indicating you are using this drug. Do not share this medication with others. Laboratory and/or medical tests may be performed to monitor your progress.

Missed Dose

If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.


Store at room temperature (77 degrees F or 25 degrees C) away from light and moisture. Brief storage between 59 and 86 degrees F (15 to 30 degrees C) is permitted.

Medical Alert

Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).