Felbamate: clinical and molecular aspects of a unique antiepileptic drug.

Felbamate was launched in 1993 in the U.S. as a "new generation" antiepileptic drug (AED) with a unique mechanism of action. It proved efficacious in patients refractory to other AEDs and was particularly beneficial in children suffering from Lennox-Gastaut syndrome, being the first drug shown to be effective at treating this condition in controlled trials. Following the occurrence of rare cases of aplastic anemia and of hepatic failure associated with the use of felbamate during early 1994, a "black-box" warning was added to the drug's package insert. Despite this, felbamate continues to be used in many patients, although not as a first-line treatment. Felbamate's dual mechanism of action--enhancing the GABA system while inhibiting excitatory amino acid responses--may explain its efficacy in a broad range of epileptic patients. A better understanding of this mechanism may lead to the development of felbamate-like drugs with a better side effect profile.