Background: Second-generation histamine H1-receptor antagonists are accepted first-line systemic therapy for seasonal allergic rhinitis. Ebastine is a new histamine H1-receptor blocker that may differ in efficacy from currently used second-generation agents.

Objective: To compare the efficacy of daily treatment with ebastine, 10 mg, ebastine, 20 mg, or cetirizine, 10 mg, for relieving symptoms of seasonal allergic rhinitis in adults.

Methods: In this multicenter, double-blind study, outpatients were randomized to one of three parallel treatment groups: ebastine, 10 mg, ebastine, 20 mg, or cetirizine, 10 mg once daily in the morning for a 2-week period. Patients were evaluated clinically according to symptoms, discomfort, and a global assessment at baseline and on days 8 and 15 of treatment. The total symptom score, defined as the sum of the total morning score on the day of evaluation and the total evening score on the preceding day, was the primary efficacy parameter.

Results: Ebastine, 20 mg (n = 111), ebastine, 10 mg (116), and cetirizine, 10 mg (116), were all effective for improving nasal and ocular symptoms. There was, however, a general trend towards more rapid relief of symptoms with ebastine, 20 mg, and this reached statistical significance in some efficacy parameters after the first week of treatment. In a subpopulation of 158 patients who presented with more severe symptoms, statistically significantly greater improvement was seen with ebastine, 20 mg, compared with ebastine, 10 mg, as indicated by the mean change from baseline in the total symptom score averaged over the treatment period (-13.7 +/- 4.7 vs -11.8 +/- 3.8; P =.027) and in the morning symptom score (-6.7 +/- 2.7 vs -5.7 +/- 2.2; P = .042). All three treatments were well tolerated. Dry mouth, headache, and somnolence were the most common adverse events.

Conclusion: Ebastine (10 mg), cetirizine (10 mg), and ebastine (20 mg) administered orally once daily for 2 weeks all appear to be effective for relieving the symptoms of seasonal allergic rhinitis. Ebastine, 20 mg, may have advantages over ebastine, 10 mg, and cetirizine, 10 mg, in terms of a reduced time to achieve maximal efficacy and a superior level of efficacy in patients with more severe symptoms.