Plasma sodium valproate levels and clinical response in epilepsy

Serial plasma levels of sodium valproate were estimated in 12 epileptic patients and 10 normal subjects after a single dose of the drug, whilst random estimations were performed in another group of 32 patients already stabilised on sodium valproate. The tentative conclusions arrived at by this study were: 1) In the majority of patients and normal subjects peak plasma levels were reached by the end of the first or second hour. 2) The majority of clinically controlled subjects showed a plasma level above 40microgram/ml. 3) Similar doses of sodium valproate (mg/kg) produced higher plasma levels in normal subjects than in the epileptic patients. Whether this is an effect of other anticonvulsants the patients were taking at the same time is a matter for conjecture. 4) Dosage and plasma levels did not appear to show a close correlation. 5) Random estimation of plasma levels are of little value for monitoring therapeutic efficacy, unless timed in relation to the dose, for reasons already mentioned above.