A randomized, placebo-controlled study of topiramate in primary generalized tonic-clonic seizures

Background and Objective: Topiramate is effective as adjunctive treatment of partial-onset seizures in adults. The efficacy and safety of topiramate as adjunctive therapy for the treatment of primary generalized tonic-clonic (PGTC) seizures were investigated in a randomized, double-blind, placebo-controlled study. Methods: Eighty patients, 3 to 59 years old, who experienced three or more PGTC seizures during an 8-week baseline phase were randomly assigned to treatment with either topiramate (n = 39) or placebo (n = 41). Topiramate was titrated to target doses of approximately 6 mg/kg/day over 8 weeks and maintained for another 12 weeks. Results: The median percentage reduction from baseline in PGTC seizure rate was 56.7% for topiramate patients and 9.0% for placebo patients (p = 0.019). The proportion of patients with 50% or higher reduction in PGTC seizure rate was 22/39 (56%) and 8/40 (20%) for the topiramate and placebo groups, respectively (p = 0.001). The median percentage reduction in the rate of all generalized seizures was 42.1% for topiramate patients and 0.9% for placebo patients (p = 0.003). The proportions of patients with 50% or higher reductions in generalized seizure rate were 18/39 (46%) and 7/41.(17%) for the topiramate and placebo groups, respectively (p = 0.003). The most common adverse events were somnolence, fatigue, weight loss, difficulty with memory, and nervousness. Treatment-Limiting adverse events occurred in one patient in the topiramate group (anorexia and weight loss) and one in the placebo group (granulocytopenia and thrombocytopenia). Conclusion: Topiramate is well-tolerated and effective for the adjunctive treatment of PGTC seizures.