Clobazam: a newly approved but well-established drug for the treatment of intractable epilepsy syndromes.

Clobazam, a 1,5-benzodiazepine, was introduced in the 1970s as an anxiolytic and antiepileptic drug. Despite worldwide usage, it was only recently approved in the United States (seizures associated with Lennox-Gastaut syndrome). This article reviews historical and recent data to help practitioners better understand clobazam's clinical properties and usage. In many clinical trials, open-label studies, and retrospective reviews, clobazam was generally associated with ≥50% seizure reduction for more than half of Lennox-Gastaut syndrome patients, with approximately 10% achieving freedom from drop attacks. Efficacy is persistent, with little evidence for development of tolerance. Clobazam's safety profile appears to be similar to that of other benzodiazepines, but with substantially decreased sedation and increased psychomotor performance. Studies suggest clobazam acts through potentiation of gamma-aminobutyric acid type A receptors in a manner similar to other benzodiazepines. However, clobazam appears to display greater selectivity for receptors responsible for anticonvulsant activity than for those involved in sedation.