Low serum leptin level is associated with zonisamide-induced weight loss in overweight female epilepsy patients.

Because iatrogenic obesity may hinder medication compliance, it would be a reasonable approach to consider antiepileptic drugs (AEDs) that promote weight loss in overweight patients. We performed an open-label, observational study to assess the effects of zonisamide on weight in overweight female epilepsy patients. In particular, we studied how the basal serum leptin level is related to changes in the weight of these patients. We recruited female epilepsy patients with basal body mass index 25 or more. Laboratory findings including serum leptin level were measured and zonisamide was administered as a monotherapy at a dose of 200 to 400mg/day. Six months later, we measured changes in the body weight. Thirty-seven female epilepsy patients enrolled in the study, and 23 of them completed the treatment. Weight loss after zonisamide treatment was correlated with initial body weight (p=0.020), follow-up weight (p=0.010), and basal serum leptin level (p=0.008), but was not correlated with patients' age, results of lipid profile, and dosage of zonisamide. The correlation of the serum leptin level with weight loss was still significant after the effect of the initial weight was adjusted (p=0.042). Our study shows that low serum leptin level is associated with weight loss in overweight female epilepsy patients. This result may be beneficial for selecting AEDs and provide clues for the pathophysiology of zonisamide-induced weight loss.