The impact of zonisamide on weight. A clinical study in 103 patients with epilepsy

To investigate the impact of zonisamide (ZNS) on body weight in patients with epilepsy. A retrospective chart analysis of weight changes after initiation of ZNS (103 patients; 54 female; age 17-68 years). For 31 patients follow-up data after ZNS-withdrawal were available. Patients were categorized according to body-mass-index (BMI) < 20, 20-25, and > 25 kg/m(2). Body weight before ZNS was 78.6 +/- 16.0 kg (range 45-120 kg), BMI 26.5 +/- 5.2 kg/m(2) (range17.6-41.3 kg/m(2)). Within 13 +/- 7.2 months of treatment, mean body weight decreased by -3.7% +/- 9.1%, showing high interindividual variability (-36% to +32%). Weight loss > 5% was documented in 35%, weight gain > 5% in 14% of patients. Weight loss was more prominent in patients being overweight prior to treatment onset. At the end of follow-up, patients with overweight had decreased by number. Weight changes under ZNS were not correlated to ZNS daily dosage. Following discontinuation of ZNS treatment weight loss proved to be reversible. Zonisamide reduced weight in 35% of patients, especially in patients with overweight prior to treatment. Weight loss is reversible following discontinuation of treatment with ZNS.