Name: Felbamate (Felbatol)
Class: Antiepileptic Agent (Complex-Partial)
Mechanism: Multiple. Blocks voltage-dependent Na+ channels ® inhib. of sustained high-freq repetitive neuron firing. Modulates strychnine-insens. glycine receptor. May enhance GABAergic neurotransmission.
Absorption: Oral ® 100% bioavail.
Dist.: 22-25% protein binding
Metabolism.: 50% hepatic, 50% renal. Excretion, t½: 20-23 hr (adults)
Toxicity/S.E.s: Most serious—aplastic anemia, acute hepatic failure. Patients & physicians both required by FDA to sign info/consent form. Most common—anorexia, n/v, insomnia, headache. Drug interactions—¯ w/phenytoin, carbamazepine.
Utility: Not DOC for anything. Monotherapy or adj. therapy of partial seizures in patients ³ 14 y.o. Adj. therapy of partial & gen. seizures assoc. w/Lennox-Gastaut synd.
Special Features: Broad-spectrum anticonvulsant. Effective as add-on & monotherapy. But multiple drug interactions, signif. S.E.s w/initial dosing, & increased risk of aplastic anemia & acute hepatic failure diminish its charm.