Drug | Daily Dosage | Optimal Blood Level ( g/ml) | Comment | Carbamazepine | 5 25 mg/kg PO divided tid-qid | 4 8 | Metabolized to active metabolite Side effects: nystagmus, dysarthria, diplopia, ataxia, drowsiness, nausea, blood dyscrasias, hepatotoxicity | Fosphenytoin | Maintenance dose: 4 6 mg/kg PE total daily dose IV/IM divided doses q8h Temporary substitution for oral Dilantin: same as daily oral Dilantin dose in mg | 10 20 (measured as phenytoin) Free level 1 2 | Fosphenytoin 75 mg = phenytoin 50 mg Maximum infusion rate 150 mg PE/min IV infusion requires continuous ECG, BP, and respiratory monitoring Administer fosphenytoin substitution doses at the same frequency as oral Dilantin Side effects: tingling, paresthesias after IV administration; other side effects similar to phenytoin | Gabapentin | 900 mg PO divided tid | | Side effects: fatigue, somnolence, dizziness, ataxia | Lamotrigine | 25 mg PO every other day if on valproic acid + enzyme inducer; 50 mg/d if not on valproic acid, but on enzyme inducer | | Side effects: rash, abnormal thinking, dizziness, ataxia, nervousness, somnolence, diplopia, nausea, vomiting, weight gain | Phenobarbital | 2 5 mg/kg PO/IV qd | 10 40 | Maximum infusion rate 50 mg/min Side effects: drowsiness, nystagmus, ataxia, skin rash, learning difficulties | Phenytoin | 4 8 mg/kg PO/IV qd | Total level:10 20 Free level 1 2 | Maximum infusion rate 50 mg/min Side effects: nystagmus, ataxia, dyskinesias, sedation, gingival hyperplasia, hirsutism, blood dyscrasias, rashes, systemic lupus erythematosus, peripheral neuropathy | Primidone | 5 20 mg/kg PO divided tid | Primidone: 5 15 Phenobarbital: 15 40 | Metabolized to phenobarbital, which contributes to pharmacologic activity Side effects: sedation, nystagmus, ataxia, vertigo, nausea, skin rashes, megaloblastic anemia | Topiramate | Goal of 200 mg PO bid Starting dose 50 mg PO bid | | Adequate fluid intake should be maintained to minimize the risk of kidney stone formation Side effects: psychomotor slowing, difficulty in concentrating, speech and language problems, somnolence and fatigue, kidney stone formation | Valproic acid | 10 60 mg/kg PO divided tid | 50 100 | Side effects: nausea, vomiting, diarrhea, drowsiness, alopecia, weight gain, hepatotoxicity, thrombocytopenia, tremor | Valproate sodium injection | 10 60 mg/kg IV divided tid-qid IV dose equals the oral dose when used as a temporary substitute for oral therapy | IV product is intended for temporary substitution of oral valproate in same daily dose and dosing interval IV dose should be infused as a 60 min infusion, but not faster than 20 mg/min | BP, blood pressure; ECG, electrocardiogram; IM, intramuscular; IV, intravenous; PE, phenytoin sodium equivalent; PO, by mouth | |