Levocetirizine - A new selective H, receptor antagonist for use in allergic disorders

Levocetirizine is the active R-enantiomer of cetirizine and represents a new second-gene ration histamine H-1 antagonist. It has a high affinity and selectivity for H-1 receptors. Comparative studies have shown evidence of superior H-1 receptor binding affinity over its racemate, cetirizine. Levocetirizine has a favorable pharmacokinetic profile; it is rapidly and extensively absorbed, minimally metabolized, and has a lower volume of distribution (V-d) than some other second-generation antihistamines. A number of studies using the histamine-induced wheal and flare model have repeatedly demonstrated marked suppressive effects for levocetirizine. Levocetirizine has also been found to be effective in relieving symptoms of seasonal and perennial allergic rhinitis, including nasal congestion, and its side effects are minor. (C) 2004 Prous Science. All rights reserved.