Levocetirizine dihydrochloride,(R)-[2-[4-[(4-chlorophenyl) phenylmethyl]-1-piperazinyl] ethoxy] acetic acid dihydrochloride, (Xyzal) is awhite, crystalline powder and is water soluble. ThisR-enantiomer is has a 30-fold higher affinity than the S-enantiomer,and dissociates more slowly from H1-receptors.Pharmacologically, it displays the same receptor and CNSselecitivity profile as the racemate, cetirizine,and thus the same therapeutic advantages. Levocetirizine isindicated for the relief of symptoms associated with allergicrhinitis (seasonal and perennial) in adults and children 6 yearsof age and older and for the treatment of the uncomplicatedskin manifestations of chronic idiopathic urticaria in adultsand children 6 years of age and older. Its pharmacokineticsand clearance profile are essentially the same as the racemate,cetirizine .
Levocetirizine hydrochloride is a nonsedating antihistamine. It is a histamine H1-receptor antagonist, the active isomer of cetirizine. Levocetirizine has high bioavailability, high affinity for and occupancy of the H1 receptor.
