FELBAMATE - A REVIEW OF ITS PHARMACODYNAMIC AND PHARMACOKINETIC PROPERTIES, AND THERAPEUTIC EFFICACY IN EPILEPSY

Felbamate is currently being developed as an antiepileptic agent. Alth ough its mechanism of action has yet to be fully elucidated. felbamate appears to inhibit both the spread of seizures and increase seizure t hreshold in animal models. Data available in the clinical selling prov ide evidence that, at doses of up to 3600 mg/day as an adjunct to exis ting antiepileptic therapy or as monotherapy following substitution fo r other medications, the drug reduces the.frequency of partial onset s eizures in adult patients refractory to conventional antiepileptic tre atments. Felbamate is also effective in the treatment of Lennox-Gastau t syndrome in children, a severe epilepsy which is usually refractory to antiepileptic agents. The effect of felbamate in the treatment of g eneralised tonic-clonic seizures in adults with partial onset seizures which are secondarily generalised is promising but requires clarifica tion in large-scale trials. The most common adverse effects occurring during administration of felbamate are mild to moderate gastrointestin al (nausea, vomiting and anorexia) and central nervous system (headach e. somnolence, diplopia, dizziness and insomnia) disturbances. Drug in teractions with other antiepileptic agents may prove problematic in te rms of adverse effects. Thus, at this stage of its development, the an tiepileptic efficacy of felbamate in treatment-refractory patients wit h partial onset seizures and Lennox-Gastaut syndrome has been proven b ut efficacy in generalised tonic-clonic seizures requires further subs tantiation in large well controlled and well designed clinical trials. In addition, a more comprehensive base of comparative clinical trials data is necessary to further clarify issues of relative efficacy and tolerability compared with other antiepileptic agents. The clinical im plications of the drug interactions associated with felbamate also req uire more detailed investigation. These data will be awaited with inte rest and when available will help to place felbamate in perspective in the management of epilepsy.