Valproic Acid in Childhood Epilepsy: Anticonvulsive Efficacy in Relation to Its Plasma Levels

In a study conducted over two years involving 90 epileptic children, valproic acid demonstrated significant anticonvulsive efficacy, particularly in those receiving it as monotherapy. Among 34 patients on sodium valproate alone, 82% achieved complete seizure control with a mean plasma level of 65.1 micrograms/ml, while 18% experienced recurrent seizures despite higher plasma levels, suggesting resistance to the drug. The study found valproic acid effective for absences, tonic-clonic seizures, and partial epilepsy. In combination therapy with phenobarbital, 64% of 22 children achieved seizure control. However, in more severe cases treated with multiple anticonvulsants, only 35% achieved control. Side effects were noted in 21% of patients on sodium valproate alone, including increased appetite, gastrointestinal disturbances, transient hair loss, and fatigue, often at plasma levels above 70 micrograms/ml. A therapeutic plasma concentration range of 40-90 micrograms/ml was suggested.