The scope and use of valproate in epilepsy.

Valproate has rapidly advanced as an antiepileptic drug in the last 15 years. This simple branched-chain fatty acid is strikingly different from previous antiepileptic drugs. Numerous clinical studies have found valproate to be highly effective in controlling generalized seizures, particularly as monotherapy. Ideally, valproate is given in three to four doses per day, because the elimination half-life varies from 6 to 15 hours, depending on concomitantly administered drugs and metabolic variations. Increasing the dosage raises the peak serum level and also increases the duration of time during which a minimum effective serum concentration is obtained. Drug interactions occur when valproate is administered with other drugs, especially other antiepileptic drugs. Side effects attributed to valproate include tremor, weight gain, hair loss, hair growth, hepatotoxicity, and neural tube defects in offspring of mothers. Monitoring serum valproate concentrations and seizure frequency are essential aspects of patient follow-up.