FELBAMATE IN THE TREATMENT OF PARTIAL-ONSET SEIZURES

Felbamate (FBM, Felbatol/Taloxa) has been the object of several trials that are innovative and unique. First, FBM is the first antiepileptic drug (AED) to have been submitted to a controlled efficacy study in p atients with the Lennox-Gastaut syndrome (LGS) before being submitted for regulatory approval. Second, FBM was tested in patients discontinu ed from other AEDs for presurgical monitoring. Third, FBM was the firs t experimental AED to have been tested in controlled monotherapy trial s. Overall, these studies succeeded in demonstrating that FBM is relat ively safe and effective against both partial-onset seizures and the g eneralized seizures occurring in the LGS. The results of some of these studies could not always be expressed by using the more familiar conc ept of percent seizure reduction because, for ethical reasons, the eff icacy variable had to be defined in terms of time to the n(th) seizure or in terms of escape criteria. This map make it more difficult to ev aluate just how effective FBM is in comparison with other AEDs. Anothe r reason why the efficacy of FBM cannot yet be fully assessed is that in all the studies the FBM dosage was limited to a maximum of 3,600 mg /day or 45 mg/kg/day. At this dosage, FBM produced no toxicity in the majority of patients, and its full therapeutic effect may have to be r e-evaluated in the future at higher dosages.