Valproate sodium enhances body weight gain in patients with childhood epilepsy: a pathogenic mechanisms and open-label clinical trial of behavior therapy.

OBJECTIVES: Excessive weight gain associated with valproate sodium (VPA) may predispose patients with epilepsy to other health problems such as insulin resistance. The purpose of this study was to examine the changes in body weight and several biochemical parameters in children receiving VPA treatment. The effects of behavior therapy for epileptic children with VPA-induced weight gain are discussed.
METHODS: Fifteen patients newly diagnosed with epilepsy were included in the study. The following parameters were measured: body weight, body mass index (BMI), serum glucose, serum insulin, serum VPA concentration and serum free carnitine. In addition, behavior therapy was introduced at the initiation of VPA therapy, and lasted at least for 2 years.
RESULTS: After 6 months of follow-up, there were eight (53%) patients in whom weight gain was demonstrated. Significant increases in the serum insulin level and the insulin/glucose ratio were observed in the weight gain group (p<0.01). All patients with significant weight gain showed increased appetite. However, BMI stopped increasing with intensive behavior therapy.
CONCLUSIONS: These findings suggest that an increase in serum insulin and insulin/glucose levels may cause weight gain, possibly by stimulating appetite, and that weight changes seem to be reversible with intensive behavior therapy without discontinuation of VPA.