Levetiracetam: A new antiepileptic drug for the adjunctive therapy of chronic epilepsy.

Levetiracetam has recently been licensed in Europe and the U.S.A. for use as an adjunctive agent in partial epilepsy with or without secondary generalization. The mode of action has yet to be elucidated, but may involve a new brain-specific binding site, the ligand for which is unknown. Levetiracetam has a favorable pharmacokinetic profile, with rapid and almost complete oral absorption, almost 100% bioavailability, linear, dose-dependent maximum plasma concentrations and minimal plasma protein binding. Excretion is mainly renal, with most of the drug being eliminated unchanged. Levetiracetam does not have an effect on the major drug-metabolizing hepatic enzymes, and thus is associated with a low incidence of interactions with other antiepileptic drugs (AEDs). These properties make it a well-tolerated drug, with the most common reported side effects being asthenia, somnolence, headache and dizziness. Antiepileptic properties of levetiracetam demonstrated in animal studies have been borne out by large double-blind, placebo-controlled clinical trials, with significantly improved responder rates (>/= 50% reduction in seizure frequency from baseline) and number of seizure- free patients versus placebo. In addition, efficacy appears to be maintained over the long term and no evidence for the development of tolerance to the effects of levetiracetam has been seen. (c) 2001 Prous Science. All rights reserved.