One-year treatment of chronic urticaria with mizolastine: efficacy and safety. URTOL study group

To assess the long-term safety and efficacy of the H1-receptor antagonist mizolastine in the symptomatic treatment of chronic urticaria (CU).

Mizolastine is a novel second generation antihistamine with additional anti-inflammatory properties which has been shown to be effective in this condition as well as in allergic rhinitis. As the drug is used for chronic treatment, a detailed study of its efficacy and safety over a prolonged period was warranted.

This open label multicentre trial recruited 211 patients suffering from CU (67% female; mean age 40+/-13 years), with > or = 1 episode/week if untreated. After a 7-day placebo run-in period, patients received mizolastine (10 or 15 mg) for 12 months. Efficacy was assessed by the patient using daily diary cards and overall condition evaluation at study visits. Clinicians also assessed the same parameters at each visit, and gave a global assessment at study termination. Safety was assessed by monitoring adverse events and laboratory parameters. Cardiac safety was monitored every 4 months using 12-lead ECGs, with particular attention to QT intervals.

The trial was completed by 127 patients. Mizolastine reduced overall discomfort from the second week of therapy, and reduced itching and the number and size of wheals, as assessed by the patients. The clinician's assessment of the proportion of patients with > 10 wheals decreased from 42% to 28% after 2 months. Clinical assessment also indicated that itch intensity and angioedema were improved by mizolastine, and the improvement was sustained throughout the trial. The investigators estimated that 70% of patients benefited from therapy. There were no drug-related serious adverse events during the study. The cardiac repolarization assessed according to the QTc intervals was not modified during prolonged administration.

Mizolastine improves CU symptoms, and these improvements are sustained over 12 months with no loss of drug sensitivity. No specific side-effects are associated with its long-term use in the current study.