title: Comparative efficacy of cetirizine and fexofenadine for seasonal allergic rhinitis, 5-12 hours postdose, in the environmental exposure unit.
abstract: In a previous study, cetirizine and fexofenadine similarly relieved seasonal allergic rhinitis symptoms in the first 5 hours, but cetirizine was more effective at 21-24 hours postdose. This randomized, double-blind, placebo-controlled study compared the response to treatment between 5 and 12 hours. Eligible ragweed allergic subjects were exposed to pollen in the Environmental Exposure Unit and randomized (n = 599) to a single dose of cetirizine, 10 mg; fexofenadine, 180 mg; or placebo (2.5:2.5:1). The primary efficacy end point was the change from baseline in total symptom severity complex (TSSC) score at 12 hours postdose. TSSC score was the sum of self-rated scores (0 = absent to 3 = severe) for runny nose, sneezing, itchy nose/palate/throat, and itchy/watery eyes, recorded half-hourly. Mean baseline TSSC scores were similar: 9.2, cetirizine and fexofenadine; 8.9, placebo. Reductions in TSSC scores from baseline were 4.3 at 12 hours and 5.0 overall (i.e., average over 5-12 hours postdose) for cetirizine and 3.4 and 4.4, respectively, for fexofenadine. Cetirizine produced a 26% greater reduction in TSSC at 12 hours (p = 0.001) and 14% greater reduction in TSSC overall (p = 0.006) compared with fexofenadine. Cetirizine and fexofenadine reduced TSSC scores (p < 0.001) and individual symptoms (p < 0.05) more than placebo. However, cetirizine was more effective than fexofenadine (p < 0.05) for runny nose and sneezing (12 hours and overall), itchy/watery eyes (12 hours), and itchy nose/throat/palate (overall). Incidence of treatment-emergent adverse events and somnolence were similar among groups: cetirizine, 25.3 and 0.8%, respectively; fexofenadine, 29.6 and 0%, respectively; placebo, 35.0 and 0%, respectively. In conclusion, cetirizine produced greater relief of seasonal allergic rhinitis symptoms than fexofenadine at 12 hours postdose and over the 5- to 12-hour postdose period.
authors.affiliation: Department of Medicine, Queen's University, Kingston, Ontario, Canada.
authors.forename: James H
authors.initials: JH
authors.lastname: Day
authors.forename: Maureen P
authors.initials: MP
authors.lastname: Briscoe
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Rafeiro
authors.forename: Jodan D
authors.initials: JD
authors.lastname: Ratz
authors.forename: Anne K
authors.initials: AK
authors.lastname: Ellis
authors.forename: Charles W
authors.initials: CW
authors.lastname: Frankish
authors.forename: Douglass
authors.initials: D
authors.lastname: Chapman
authors.forename: Emilio C
authors.initials: EC
authors.lastname: deGuia
authors.forename: Benjamin
authors.initials: B
authors.lastname: Kramer
authors.forename: Christopher
authors.initials: C
authors.lastname: Warner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000485:Allergens; D018926:Anti-Allergic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D017332:Cetirizine / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006634:Histamine H1 Antagonists / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011058:Pollen; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000188:drug therapy*; D016593:Terfenadine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D000485:Allergens; D018926:Anti-Allergic Agents; D006634:Histamine H1 Antagonists; D016593:Terfenadine; C093230:fexofenadine; D017332:Cetirizine