Valproate sodium in epilepsy. A clinical trial including monitoring of drug levels.

Sodium valproate was used as monotherapy in 90 cases with epilepsy who had at least one fit per week, irrespective of the type of seizures. The effect of the drug was evaluated on the basis of change in seizure frequency. Serum valproic acid levels were estimated by homogenous enzyme immunoassay. All the patients with absence (5/5) and myoclonic (3/3) seizures and 80% (42/53) of cases with generalized tonic-clonic seizures, became seizure free. Six of ten patients with only tonic seizures became seizure free. An average daily dose of 19.6 mg/kg provided a mean valproic acid level of 81.4 micrograms/ml in all seizure free patients. No correlation could be established between valproate dose and serum levels. Mild transient side effects were noted. No haematologic abnormality or hepatotoxicity was observed. Valproate sodium effectively controlled seizures in a majority of patients with partial seizures. Serum level monitoring helps to establish an optimal dose to keep the patient seizure free. No correlation could be established between side effects and serum levels.