Comparative therapeutic effect and safety of mizolastine and loratadine in chronic idiopathic urticaria. URTILOR study group.

Mizolastine, a new second-generation H1 receptor antagonist with additional anti-allergic properties, was compared with loratadine in 61 patients suffering from severe chronic idiopathic urticaria (CIU). In this double-blind study, patients were randomly allocated to receive either mizolastine 10 mg (n = 26) or loratadine 10 mg (n = 35) once-daily for 28 days. Both compounds were well tolerated, safe and efficacious. The reduction in the number of episodes per week (5. 6+/-16.3 and 6.4+/-12.4 for mizolastine and loratadine, respectively) and the reduction in the symptom severity score, measured using a Visual Analogue Scale (VAS), were comparable (30.2 +/- 39.0 mm and 30.5 +/- 28.5 mm for mizolastine and loratadine, respectively). Mizolastine had a positive effect on angioedema (85% CI 95% [0.69-1.00]) of patients improved compared with 75% (CI 95% [0.59-0.91]) of the loratadine group and the differential reduction of the mean total duration of episodes in the mizolastine group was higher when compared with the loratadine group (from 13.7 +/- 33.5 hours on day 0 to 5.1 +/- 9.0 hours over the treatment period and from 8.2 +/- 8.8 hours on day 0 to 5.1 +/- 7.8 hours over the treatment period for mizolastine and loratadine, respectively). Prick test analysis demonstrated that both drugs caused a significant decrease of histamine-induced wheal and flare with no development of tolerance, with a significant superiority of mizolastine over loratadine for some histamine concentrations. Mizolastine and loratadine both proved very efficacious and safe. In addition mizolastine demonstrated a superiority in prick tests, beneficial effects on angioedema and seemed to provide a faster onset of action.