Double-blind, placebo-controlled study comparing the efficacy and safety of fexofenadine hydrochloride (120 and 180 mg once daily) and cetirizine in seasonal allergic rhinitis

Background: Fexofenadine hydrochloride (HCl) is a new HI antihistamine used twice daily in some countries. Objective: A multicenter, double-blind, parallel-group, placebo-controlled trial compared the efficacy and safety of fexofenadine HCl (120 and 180 mg administered once daily) and cetirizine (10 mg once daily) in the treatment of seasonal allergic rhinitis, Methods: After a 3- to 5-day run-in period, patients meeting entrance crite ria were randomized to receive placebo, fexofenadine HCl 120 mg once daily, fexofenadine HCl 180 mg once daily, or cetirizine 10 mg once daily (active control) for 2 weeks, Eight hundred twenty-one patients comprised the inte ntion-to-treat population and 722 patients completed the study, Symptom ass essments were conducted 12 hours after the dose for the previous 12 hours a nd again at 24 hours after the dose for the previous 12 hours. In addition, assessment was made immediately before dosing in the morning for the previ ous 30 minutes. Total symptom score was calculated as the sum of scores for the 4 individual symptoms: (1) sneezing, (2) rhinorrhea, (3) itchy nose, p alate, or throat, and (4) itchy, watery, or red eyes; the nasal congestion score was also recorded. Results: Both doses of fexofenadine HCl were superior to placebo in reducin g the total symptom score. Efficacy was maintained for the entire dosing in terval (ie, for 24 hours). There were no differences in efficacy between th e 2 doses of fexofenadine HCl or between either dose of fexofenadine HCl an d cetirizine, There was no major side effect, but the combined incidence of drowsiness or fatigue was greater with cetirizine (9%) than with placebo ( 4%) (P = .07) or fexofenadine (4%) (P = .02), Conclusions: Once-daily fexofenadine is thus a valuable addition to the non sedating group of H-1 receptor antagonists currently available for the trea tment of seasonal allergic rhinitis.