Abstracts

RATIONALE: Zonisamide (Zonegran?, ZNS) is a new antiepilepsy drug (AED) with both sodium and calcium channel blocking activities. ZNS has been available in Japan for over 10 years, during which time clinicians have gained substantial experience in using the drug. Several studies have been conducted in the US evaluating the efficacy and safety of ZNS. Efficacy values often presented in clinical studies include mean or median percent reduction in seizures and response rate (percent of patients experiencing a 50 % reduction in seizure frequency). Additionally, identification of patients who have become seizure free on AEDs for long time intervals may provide valuable insight into recognizing types of patients who may respond to and tolerate new medications. OBJECTIVE: To evaluate long-term benefits of ZNS. METHODS: Data from four separate, ongoing trials at a single center were reviewed. Forty patients, 20 males and 20 females, were initiated on ZNS between 1994-1999. Duration of follow-up was 9-71 (median=67) months. All had refractory partial epilepsy and had failed standard drugs. Patients ages ranged from 20-72 years. Baseline seizure frequency ranged from 2-80 (median=6.5) seizures/month. RESULTS: Eight patients (20%) have maintained a >80% seizure reduction, of whom 5 (12.5%) have been seizure free from 8-71 (mean=31.4, median=10) months. CONCLUSIONS: These data suggest that long-term seizure remissions are possible in previously refractory patients receiving ZNS. There does not appear to be evidence of tachyphylaxis. Funded by Elan Pharmaceuticals.