Efficacy and tolerability of zonisamide in idiopathic generalized epilepsy.

OBJECTIVE The objective of this study is to evaluate the efficacy and safety of zonisamide (ZNS) for the treatment of idiopathic generalized epilepsies (IGEs). METHODS Thirteen patients with different types of IGEs who were treated with ZNS between the years 2006 and 2008 were identified. Efficacy and tolerability were assessed at months 6 and 12 post-treatment. Response was defined as a 50% or greater reduction in seizure frequency. RESULTS Twelve patients (92.3%) continued with ZNS at month 6, and 11 (84.6%) at month 12. Mean daily dose was 319 mg (range 100-500 mg/d). Response was achieved at month 6 in eight of the 12 patients that continued with ZNS (66.6%), of which 7 were seizure-free (58.3%). At month 12, eight of the 11 patients that continued with ZNS were responders (72.7%) and 6 were seizure-free (63.6%). For different types of seizures, better responses were observed for absences and generalized tonic-clonic seizures. Four out of 13 patients (30.7%) experienced adverse events and in two (15.3%), these led to withdrawal. CONCLUSION In this retrospective study, ZNS showed efficacy and tolerability for the treatment of different types of IGEs. Limitations include a small sample size and a relatively short period of follow-up. Our results are promising and justify the need for prospective controlled trials in IGE.