title: H1-antihistaminic activity of cetirizine and fexofenadine in allergic children.
abstract: The clinical pharmacology of H1-antihistamines has not yet been optimally studied in children and other special groups of patients. Our objective was to determine the onset, extent, and duration of H1-antihistaminic activity of cetirizine and fexofenadine in the pediatric population. We performed a prospective, randomized, placebo-controlled, double-blind, crossover, single-dose study of these H1-antihistamines in 15 allergic children, mean+/-SEM age 8.8+/-0.5 years. We used suppression of the histamine-induced wheal and flare as the primary outcome. Compared with pre-dose baseline, cetirizine 10 mg suppressed the wheals significantly (p<or=0.05) from 2 to 24 h and the flares significantly from 1 to 24 h, achieving 77+/-SEM 10% to 86+/-9% suppression of the wheal from 2 to 7 h and 85+/-6% to 88+/-6% suppression of the flare from 2 to 24 h, inclusive. Compared with baseline, fexofenadine 30 mg did not suppress the wheals or flares significantly at any time, achieving 40+/-9% to 54+/-9% wheal suppression from 2 to 7 h and 45+/-11% to 68+/-9% flare suppression from 2 to 7 h, inclusive. Compared with placebo, cetirizine suppressed the wheals and flares significantly from 2 to 24 h. Compared with placebo, fexofenadine suppressed the wheals significantly at 4 and 6 h, and the flares from 4 to 7 h. Cetirizine suppressed the wheals and flares significantly more than fexofenadine at 2 h (wheals), and at 3 and 24 h (flares). Placebo did not suppress the wheals and flares significantly at any time. In children age 6-11 years, cetirizine 10 mg has a rapid onset of H1-antihistaminic activity, a 24-h duration of action, and greater H1-activity than fexofenadine 30 mg. Higher doses of fexofenadine should be tested in children.
authors.affiliation: John Buhler Research Center Allergy Laboratory, Faculty of Medicine, Faculty of Pharmacy, University of Manitoba, Winnipeg, Manitoba, Canada. lmcniven@hsc.mb.ca
authors.forename: F Estelle R
authors.initials: FE
authors.lastname: Simons
authors.forename: Michael
authors.initials: M
authors.lastname: J  Semus
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Goritz
authors.forename: Keith J
authors.initials: KJ
authors.lastname: Simons
mesh_terms: D018926:Anti-Allergic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D017332:Cetirizine / Q000008:administration & dosage / Q000627:therapeutic use*; D002648:Child; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006634:Histamine H1 Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012221:Rhinitis, Allergic, Perennial / Q000188:drug therapy* / Q000276:immunology; D012882:Skin Tests; D016593:Terfenadine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D018926:Anti-Allergic Agents; D006634:Histamine H1 Antagonists; D016593:Terfenadine; C093230:fexofenadine; D017332:Cetirizine