PRECAUTIONS: Tell your doctor your medical history, especially of: liver problems, pancreas problems (pancreatitis), blood problems (e.g., thrombocytopenia), metabolism problems (e.g., hyperammonemia, thyroid disorders, urea cycle disorder), seizure history/description, mental retardation, depression, brain disease, recent head trauma, upcoming surgery. 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 should be used with caution in children, especially less than 2 years of age, because they may be more likely to have serious side effects (e.g., liver damage) from this medication. Caution is advised when using this drug in the elderly because they may be more sensitive to the effects of the drug. This medication is not recommended for use during pregnancy. Consult your doctor for more details. This medication passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Tell your doctor of all prescription and nonprescription medication you may use, especially: other anti- seizure medication (e.g., phenytoin, phenobarbital, carbamazepine, felbamate, clonazepam, ethosuximide, lamotrigine, primidone), tricyclic antidepressants (e.g., amitriptyline, nortriptyline), rifamycins (e.g., rifampin, rifabutin), certain diabetes medication (e.g., tolbutamide), warfarin, aspirin, erythromycin, zidovudine. Tell your doctor if you take any 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 such as chlorpromazine), muscle relaxants, certain antihistamines (e.g., diphenhydramine). 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 these products. This drug may interfere with certain laboratory tests (e.g., urine ketones and thyroid function tests). Make sure laboratory personnel and your doctors know you use this drug.

Report Problems to the Food and Drug Administration 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. Need help identifying pills and medications? Use the pill identifier tool on RxList.