Efficacy and safety of mizolastine in seasonal allergic rhinitis. The Rhinase Study Group.

Background: Mizolastine is a new, nonsedating antihistamine under clinical investigation for treatment of allergic rhinitis and urticaria.

Objective: The purpose of this study was to determine the optimally active dose of once-daily mizolastine in seasonal allergic rhinitis.

Methods: This multicenter, double-blind, parallel study involved 494 patients randomly allocated to mizolastine (5, 10, or 15 mg) or placebo for 2 weeks.

Results: Physicians' assessments indicated the superiority of 10 and 15 mg mizolastine to placebo in reducing total symptom scores (P=.002), nasal scores (P=.004), and ocular scores (P=.007) at day 7. Patients' diaries showed a significant change from baseline in daily symptom scores as early as day 2 (P=.01) in 10- and 15-mg mizolastine groups in comparison to placebo, but this was not maintained throughout the study. No additional benefits were demonstrated during the second week of treatment in terms of efficacy. Adverse events were slightly more frequent in the 15-mg mizolastine group.

Conclusion: This study conforms mizolastine is an effective and well tolerated antihistamine in the treatment of seasonal allergic rhinitis; 10 mg is the optimal dose.