Comparative clinical efficacy, onset and duration of action of levocetirizine and desloratadine for symptoms of seasonal allergic rhinitis in subjects evaluated in the Environmental Exposure Unit (EEU).

Author(s): Day JH, Briscoe MP, Rafeiro E, Ratz JD

Affiliation(s): Division of Allergy and Immunology, Kingston General Hospital, Kingston, Ontario, Canada. dayj@kgh.kari.net

Publication date & source: 2004-02, Int J Clin Pract., 58(2):109-18.

Publication type: Clinical Trial; Randomized Controlled Trial

The Environmental Exposure Unit, an indoor pollen challenge system to test anti-allergic medications, was used to compare the onset and duration of action and the efficacy of levocetirizine and desloratadine, two recently developed H1-antagonists. In this double-blind, placebo-controlled, parallel-group study, qualified subjects were randomised to once-daily levocetirizine 5 mg (n = 141), desloratadine 5 mg (n = 140) or placebo (n = 92) and exposed to ragweed pollen on two consecutive days (7 h and 6 h). Symptoms were self-rated every 30 min. On both days, levocetirizine produced a greater improvement in the major symptom complex score (primary efficacy variable) than desloratadine (p = 0.015); both were better than placebo (p < 0.001). Levocetirizine acted earlier (1 h vs. 3 h) and produced greater symptom relief at 24 h than desloratadine (p = 0.003). Levocetirizine also alleviated nasal obstruction better than desloratadine (p = 0.007) on day 1; and better than placebo (p = 0.014) after the second dose on day 2, which was not observed with desloratadine. Levocetirizine and desloratadine were safe and well tolerated.