Abstracts

Zonisamide (ZNS) has predominantly been used in adult patients with partial seizures as an adjunctive anti-epileptic drug (AED). However, current knowledge is limited on the long-term efficacy of ZNS monotherapy. A survey of our database was conducted to investigate the profile of patients, who were successfully treated by ZNS monotherapy. From a cohort of 793 epileptic patients that had been treated with zonisamide in the past with or without other AEDs, 51 patients were selected for this study. The inclusion criteria of the 51 patients were 1) 29 pediatric patients under 16 years of age and 22 adult patients, having either partial or generalized seizures; 2) the seizure frequency before introduction of ZNS was reduced by 50% or more for longer than 4 months as a result of ZNS monotherapy; 3) patient data from May 1985 to December 2001. The age of the 51 patients, 24 males and 27 females, when ZNS monotherapy was started ranged from 6 months to 45 years and the duration from 9 to 180 months. Fifteen patients were treated with ZNS as their initial AED, 8 patients started ZNS monotherapy after skin rash developed with previous AEDs , 29 patients gradually started ZNS monotherapy due to insufficient efficacy of their previous mono- or bi-therapy of VPA, PHT, CBZ, PB, or DZP. ZNS monotherapy showed efficacy in controlling simple and complex partial seizures and secondarily generalized tonic-clonic seizures of temporal lobe epilepsy in 11 patients, frontal lobe epilepsy in 7 patients, occipital lobe epilepsy in 8 patients, and other symptomatic localization-related epilepsies in 6 patients. ZNS monotherapy was effective in controlling generalized tonic seizures including drop attack or violent head-nodding, generalized tonic-clonic seizures combined with atypical absences, myoclonic seizures and multiple seizures of symptomatic generalized epilepsy in 9 patients, including 1 patient with Lennox-Gastaut syndrome. ZNS monotherapy effectively controlled West syndrome in 2 patients, undetermined epilepsy in 2 patients, familial essential myoclonus and epilepsy in 2 patients and myoclonic epilepsy with ragged red fibers in 1 patient. ZNS monotherapy also controlled the seizures in idiopathic epilepsy in 3 patients, generalized tonic-clonic seizures on awakening in 2 patients, Sylvian seizures of benign partial epilepsy of childhood in 1 patient. ZNS monotherapy was continued in 38 patients, in that 32 patients showed remarkable improvement of their QOL. ZNS monotherapy had to be discontinued in 13 patients, due to lack of efficacy in 10 patients, overt restlessness and insomnia in 2 patients, and failure to take ZNS that resulted in a relapse of seizures in 1 patient. ZNS was found to be effective both in pediatric and adult patients in controlling partial seizures with or without secondarily generalized seizures, and also convulsive and non-convulsive generalized seizures. (Supported by a grant from Elan Pharmaceuticals, Inc.)