Zonisamide (ZNS) is a broad-spectrum antiepileptic drug in both animal models of epilepsy and patients with epilepsy. It is effective for both localization-related and generalized epilepsies and appears to be particularly potent in progressive myoclonic epilepsy syndromes. Its pharmokinetic profile is favorable, with a long half-life and low protein binding. However, its insolubility may make the development of a parenteral formulation difficult. Its safety profile is good, although teratogenicity in animal models is of concern. Adult doses of 400–600 mg per day in two doses, with blood levels from 20 to 30 mg/ml, appear to be effective.