title: Clinical pharmacology of the H1-receptor antagonists cetirizine and loratadine in children.
abstract: H1-receptor antagonists are widely used in children but are not as well-studied in children as they are in adults. Our objective was to determine the onset and duration of action and the relative potency of the H1-receptor antagonists cetirizine and loratadine in children. We performed a prospective, randomized, placebo-controlled, double-blind, crossover, single-dose study of cetirizine and loratadine using suppression of the histamine-induced wheal and flare as the primary outcome. In 15 allergic children, mean age 9 years, compared with baseline, cetirizine (10 mg) suppressed the wheals and flares significantly from 0.25 to 24 h, achieving nearly 100% of flare suppression from 2 to 24 h, inclusive, and loratadine (10 mg) suppressed the wheals and flares significantly from 0.75 to 24 h, inclusive. Cetirizine suppressed the wheals and flares significantly more than loratadine from 0.25 to 1 h, inclusive, and at 0.5, 1, 2, 3, 5, 6, 7, and 24 h, respectively. Placebo also suppressed the wheal and flare significantly at some assessment times. Cetirizine and loratadine both have excellent antihistaminic activity in children, with a rapid onset of action and a 24-h duration of action in this population.
authors.affiliation: Health Sciences Clinical Research Center, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
authors.forename: F E
authors.initials: FE
authors.lastname: Simons
authors.forename: L
authors.initials: L
authors.lastname: Johnston
authors.forename: K J
authors.initials: KJ
authors.lastname: Simons
mesh_terms: D018926:Anti-Allergic Agents / Q000627:therapeutic use*; D017332:Cetirizine / Q000627:therapeutic use*; D002648:Child; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006634:Histamine H1 Antagonists / Q000627:therapeutic use*; D006801:Humans; D017336:Loratadine / Q000627:therapeutic use*; D011446:Prospective Studies; D006255:Rhinitis, Allergic, Seasonal / Q000188:drug therapy*; D016896:Treatment Outcome; D014581:Urticaria / Q000188:drug therapy*
chemical_list: D018926:Anti-Allergic Agents; D006634:Histamine H1 Antagonists; D017336:Loratadine; D017332:Cetirizine