Indications & Dose: EPILEPSY Adjuvant therapy PO Adult Initially 25mg at HS 1 wk, may be increase by 25-50mg at 1-2 wk intervals, doses >25mg/day must be in 2 divided doses, max 800mg/day | Mono therapy PO Adult Initially 25mg at HS 1 wk, may increase by 25-50mg q1-2wk, doses >25mg/day must be in 2 divided doses max 400mg/day Child 6-10 yr: Initially 0.5-1mg/kg at HS 1 wk, increase by 0.5-1mg/kg q1-2wk max 16mg/kg/day | MIGRAINE Prophylactic therapy PO Adult Initially 25mg OD, may increase weekly by 25mg/day, max 100mg/day in 2 divided doses | PARTIAL SEIZURES Adjuvant therapy PO Adult Initially 25mg OD/BID 1 wk, may increase weekly by 25-50mg/day according to response, MD 100-200mg BID Child >2 yr: Initially 25mg as single dose at HS 1 wk, then increase by 1-3mg/kg q1-2wk, doses >25mg must be in divided doses, max 30mg/kg | Mono therapy PO Adult Initially 25mg BID, may increase weekly by 50mg/day up to 100mg BID, may further increase weekly by 100mg/day, max 200mg BID

Precautions: Avoid abrupt withdrawal, hepatic/renal impairment, porphyria

ADR: Serious: SJS, TEN, thrombocytopenia, Others: nausea, diarrhea, abdominal pain, dyspepsia, weight loss, anorexia, paresthesia, hypoesthesia, fatigue, headache, dizziness, drowsiness, insomnia, anxiety

DDI: Serious Alcohol causes additive sedative effect, Irinotecan clearance is increased, Levonorgestrel efficacy is reduced, Valproic acid increased risk of encephalopathy (in patients with pre-existing encephalopathy, Phenytoin/Haloperidol levels are increased, Ethinylestradiol levels are modestly reduced, Digoxin levels are reduced, Zonisamide may increase the risk of renal calculi, Ethinyl estradiol plus cyproterone contraceptive efficacy is reduced, Lithium toxicity is increased Others Phenobarbital/Carbamazepine decreases drug serum level

Diet: With/without food

Monitor: Hydration status, electrolytes, symptoms of acidosis, IOP, seizure frequency