Zonisamide in the management of epilepsy—Japanese experience

Zonisamide (Zonegran®), a novel antiepileptic drug (AED) approved in Europe for the adjunctive treatment of refractory partial seizures in adults, has undergone extensive evaluation in pre- and post-marketing double-blind and open-label studies in Japan (where zonisamide is used widely to treat partial and generalised seizures in adults and children). These data indicate that the clinical benefit of zonisamide extends across a range of seizure types and patient ages. In an analysis based on a mixture of controlled and open studies in adults and children with partial seizures, 51–57% responded to zonisamide treatment (achieving ≥50% reduction in baseline seizure frequency). Efficacy extends across a range of generalised seizures and 22–66% of adults and children experiencing tonic–clonic, tonic, clonic, myoclonic or absence seizures responded to treatment. Even greater responder rates have been reported when zonisamide was used as monotherapy for partial seizures and generalised seizures in patients refractory to other AEDs or with newly diagnosed epilepsy. Zonisamide is also efficacious in paediatric epilepsy syndromes, including Lennox-Gastaut Syndrome, West Syndrome and Ohtahara Syndrome. Across the spectrum of epilepsy syndromes studied, zonisamide is well-tolerated with a low incidence of adverse events, which are generally mild and CNS-related. These data indicate that zonisamide represents a valuable broad-spectrum option for the treatment of epilepsy.