Use of topiramate in childhood generalized seizure disorders.

Topiramate is a sulfamate derivative of the naturally occurring monosaccharide D-fructose. It was initially approved in the United States as adjunctive therapy for partial seizures in 1997. However, there is increasing evidence that it is effective in the treatment of generalized seizures and epilepsy syndromes. Initially, open-label studies using topiramate as add-on therapy in children with refractory generalized seizure types were performed. These showed improvement in patients with the following generalized seizure types: typical and atypical absence, atonic, myoclonic, generalized tonic-clonic, and juvenile myoclonic epilepsy. Double-blind, placebo-controlled multicentered studies in patients with refractory primary generalized tonic-clonic seizures and epilepsy syndromes were performed. The median reduction in seizure frequency for primary generalized tonic-clonic seizures was 56.7% for topiramate and 9% for placebo. Additionally, 13.6% of topiramate-treated patients were primary generalized tonic-clonic seizure free for the study period. In the topiramate-treated juvenile myoclonic epilepsy patients, primary generalized tonic-clonic seizures were reduced > 50% in 73% of patients. Open-label extension showed that primary generalized tonic-clonic seizures were reduced >50% in 63% of topiramate-treated patients for > or = 6 months, and 16% were primary generalized tonic-clonic seizure free > or = 6 months. Accumulating evidence suggests that topiramate has a broad spectrum of antiepileptic effect. Moreover, life-threatening organ toxicity has not been attributed to topiramate. Topiramate is an effective treatment for refractory generalized seizure types and epilepsy syndromes encountered in children.