Comparison of the efficacy, safety, and onset of action of mizolastine, cetirizine, and placebo in the management of seasonal allergic rhinoconjunctivitis

Background: Mizolastine is a potent and selective H-1-receptor antagonist w ith additional anti-allergic properties. Objective: The aim of this European multicenter, randomized, double-blind s tudy was to compare the efficacy of mizolastine 10 mg (n = 122), cetirizine 10 mg (n = 125), and placebo (n = 128) once daily for 28 days in patients with seasonal allergic rhinoconjunctivitis (SAR), with focus on the onset o f action. Methods: Symptoms were evaluated by the investigator using a total symptom score (TS) and by the patient (first week). Responders (R) were patients wi th a TS decrease of at least 50%. Safety was assessed according to the spon taneous reporting of adverse events. Results: Both mizolastine and cetirizine were effective in relieving the sy mptoms of SAR. After 7 days of treatment, the improvement in TS and respond er's rate were significantly (P <.05) greater in patients treated with mizo lastine (TS change versus baseline, mean +/- SD: -6.40 +/- 5.71; R: 55%) an d cetirizine (TS change versus baseline: -6.24 +/- 5.24; R: 53%) than with placebo (TS change versus baseline: -4.11 +/- 5.91; R: 40%). Both drugs act ed rapidly, within 2 hours of the first intake. During the first 3 days, mi zolastine relieved symptoms more effectively than cetirizine, the differenc e being significant on the second (P =.027) and third (P =.050) day. Both m izolastine and cetirizine were well tolerated. Conclusion: Mizolastine 10 mg once daily is at least as effective as cetiri zine in relieving symptoms of SAR, onset of action is rapid with clinical e ffect evident within 2 hours.