Efficacy of zonisamide: our experience

The current overview of zonisamide use and effectiveness is based on both a long-term prospective postmarketing survey and current zonisamide use at the Saitama Medical College, Department of Neuropsychiatry. Survey data, which were collected from individual physicians and 23 survey groups throughout Japan, assessed the effectiveness of zonisamide in 1631 patients. Zonisamide was highly effective for treating partial seizures, with 70% of patients reporting improvement. More than half of patients with generalized seizures (58%) and half of patients with myoclonic and atypical absence seizures showed improvement with zonisamide treatment. Among the different epileptic syndromes, zonisamide was highly effective in treating generalized idiopathic epilepsy (> or =78% improvement) and partial epilepsy (> or =58% improvement). However, only 28% of patients with West syndrome or Lennox-Gastaut syndrome showed improvement. Among 60 outpatients treated with zonisamide at our facility as of October 1998, most had partial seizures or generalized seizures subsequent to partial seizures. The majority of patients received zonisamide in combination with other antiepilepsy drugs. Patients receiving zonisamide monotherapy showed greater improvement than did patients receiving polytherapy. We conclude that zonisamide is highly effective for partial seizures and generalized seizures, and that there appears to be no decrease in efficacy with long-term use.