Four antiseizure drugs have been approved in the United States since 2008. Clobazam, a 1,5-benzodiazepine, was approved in October 2011 as an adjunctive therapy for Lennox-Gastaut syndrome (LGS) in patients 2 years and older. Lacosamide, an amino acid that selectively enhances the slow inactivation of voltage-gated sodium channels, was approved in October 2008 as an add-on therapy for partial onset seizures in patients 17 years and older. Rufinamide, a triazole derivative, was approved in November 2008 as an adjunctive therapy for LGS in patients 4 years and older. Vigabatrin, an irreversible inhibitor of GABA transaminase, was approved in August 2009 for the treatment of infantile spasms in children ages 1 month to 2 years and intractable complex partial seizures in adults.