Comparative trial of valproate sodium and clonazepam in chronic epilepsy.

A crossover comparative study of valproate sodium and clonazepam in the treatment of 32 adult epileptic patients receiving multiple drug therapy is described. Serum concentrations of other anticonvulsant drugs were unchanged by the addition of clonazepam. However, patients receiving high doses of other anticonvulsant drugs had lower serum concentrations of clonazepam (p less than .01). With valproate sodium, phenobarbital concentrations increased (P less than .05) in patients receiving phenobarbital but not significantly in patients receiving primidone. Phenytoin concentrations were reduced (P less than .05) during treatment with valproate sodium. Both drugs significantly reduced the frequency of minor seizures, with valproate sodium having the greater effect. However, it is important to monitor serum concentrations of other anticonvulsant drugs during treatment with valproate sodium since changes in these may influence seizure control or cause side effects.