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.