Plasma levels of sodium valproate in childhood epilepsy

Sodium Valproate levels in plasma have been measured in 207 children with epilepsy, only 21 of whom were in-patients. No significant correlation could be found between plasma levels and dose of Sodium Valproate expressed as mg/day, mg/kg body weight or mg/m2 surface area. This finding could not be attributed to irregular compliance, concomitant administration of other anticonvulsant drugs, time of sampling after last dose, duration of treatment or age of the child. We could find no evidence of a therapeutic range of plasma levels of Sodium Valproate and the ranges associated with poor (17%), moderate (44%) or good control (39%) of fits were not significantly different. The average daily dose producing an improvement in seizure control was calculated to be 30 mg/kg.