Mechanism of Action
Cetirizine is a metabolite of hydroxyzine, a first generation piperazine antihistamine. It produces selective inhibition of peripheral histamine (H1) receptors. Cetirizine has minimal anticholinergic or antiserotonergic activity and has limited penetration into the brain. At doses of 5 to 10 mg, it strongly inhibits wheal and flare reactions after intradermal histamine injection in both children and adults. Levocetirizine is the active R enantiomer of cetirizine. It has an affinity for H1 receptors approximately 2-fold higher than racemic cetirizine. At a dose of 5 mg, levocetirizine inhibits wheal and flare reactions in children and adults for up to 24 hours.[1–5]
Pediatr Pharm. 2010;16(6) © 2010
Cite this: Cetirizine and Levocetirizine Use in Children - Medscape - Jun 01, 2010.