Double-blind, parallel, randomized pilot study comparing the efficacy and tolerance of cetirizine 10 mg, mequitazine 2 � 5 mg and placebo in the treatment of patients suffering from chronic urticaria: Comparison of suppressive effects on histamine-induced weals and flares

In a double-blind, randomized, parallel-group study, 29 adult patients suffering from chronic urticaria were treated with either cetirizine 10 mg od (n = 10), mequitazine 5 mg bid (n = 10), or placebo (n = 9) for 3 weeks. Three symptoms (weals, erythema, pruritus) were rated according to severity (none, mild, moderate, severe) by the investigator at each of the four visits (days 1, 3, 14, 21). At each visit the investigator and patients also assessed the patients' general condition using a 5-point scoring system (very bad, bad, moderate, good, very good). On day 21 the global evaluation of efficacy and tolerance was assessed by the investigator and patients on a 4-point scale (excellent, good, moderate, bad). Also, a histamine skin-prick test was performed on days 3, 14, and 21. Evaluation of safety was based on the frequency of patients reporting adverse events as well as the clinical laboratory results. The cetirizine, mequitazine, and placebo groups of patients were comparable at inclusion. Overall compliance with the trial schedule was excellent for all groups. After 3 days of treatment a significant improvement in control of all urticaria symptoms was observed in the cetirizine group. Cetirizine elicited a statistically significant better control of pruritus (P = 0.006) and erythema (P = 0.018) than mequitazine on day 21. A trend in favor of cetirizine vs. mequitazine was also observed regarding control of weals (P = 0.114). Cetirizine clearly and rapidly improved the general condition of the patient as evaluated by both patients and investigator compared to the baseline results. The differences vs. mequitazine as well as vs. placebo were statistically significant on every visit, starting from day 3. After three weeks of treatment, the clinical efficacy results in the cetirizine group were rated by both patients and investigator as excellent or good, which was statistically significantly better than the results obtained in the mequitazine and placebo group (P > 0.05). The histamine skin-prick test results revealed a marked difference for the group treated with cetirizine compared to the two other groups in favor of CTZ. On day 3, cetirizine produced a statistically significant suppression of the weals (98%) and flares (74%), compared to 24% and 3%, respectively, by mequitazine. With respect to the tolerance results, no statistically significant differences were observed between the three groups. The safety profile was similar for all groups. No serious adverse event has been reported during the present study, nor did the treatments induce any clinically significant abnormal changes in the laboratory tests. It can be concluded from the present study that the effect of cetirizine was statistically and clinically significantly superior to that of mequitazine. On the other hand, of all parameters studied there were no marked differences between the patients of the mequitazine group and the patients of the placebo group. Drug Dev. Res. 43:185–192, 1998. © 1998 Wiley-Liss, Inc.