Safety of 25- and 50-mg capsules in the initiation of zonisamide therapy in patients with epilepsy: an uncontrolled, open-label study.
OBJECTIVE: This study was designed to assess the safety of 25- and 50-mg dosage strengths of zonisamide for initial titration in patients with epilepsy. RESEARCH DESIGN AND METHODS: This phase 3, multicenter, open-label, uncontrolled study conducted at 26 study sites in the United States included male and female patients with epilepsy >or= 12 years of age. After a screening visit, subjects began zonisamide therapy at a dosage depending on their body weight. Zonisamide was titrated to 100 mg/day. MAIN OUTCOME MEASURES: At the study's conclusion, information regarding adverse events (AEs) and body weight was recorded. RESULTS: One hundred forty-three subjects enrolled and received at least one zonisamide dose. Of these subjects, 125 reached at least the 100-mg dosage before terminating the study. Eighty-two subjects (57.3%) experienced at least one AE. Most commonly reported AEs included headache, somnolence, asthenia, rhinitis, nausea, and rash. No significant change in patient body weight was noted during the study (95% confidence interval: -0.1, 0.6). CONCLUSIONS: Study limitations include the open-label design and the lack of direct comparison between lower (25- and 50-mg) and higher (100-mg) starting dosages. Despite these limitations, the 25- and 50-mg zonisamide dosage formulations were well tolerated in this study.