Felbamate

Felbamate (Felbatol) is an antiepileptic drug approved by the FDA for the treatment of adults with partial seizures and children with Lennox-Gastaut Syndrome. Felbamate has more complicated pharmacokinetics and more drug interactions than many other antiepileptic drugs.  The elimination half-life ranges from 16 to 22 hours. 

Daily doses in the range of 1,200 to 3,600 mg per day normally produce plasma concentrations of 25 to 100 ug/mL. Optimal plasma levels are 30 ug/mL to 80 ug/mL. Toxicity may be encountered at levels greater than 100 ug/mL. Toxic levels of Felbamate can cause aplastic anemia or hepatic failure

Felbamate levels are measured by liquid chromatography/tandem mass spectrometry. Specimen requirement is one plain red top or green top tube of blood drawn one hour prior to the next dose.

Reference

Schmidt D. Felbamate: successful development of a new compound for the treatment of epilepsy. Epilepsia, 1996;34(Suppl 7):S30-S33.