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

OBJECTIVE: To investigate the impact of zonisamide (ZNS) on body weight in patients with epilepsy. METHODS: 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). RESULTS: 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. CONCLUSION: 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.