The treatment of mild to severe chronic idiopathic urticaria with astemizole: double-blind and open trials.

Astemizole is a new H1 histamine-receptor antagonist that has a long elimination half-life and high H1-receptor affinity. This double-blind study evaluated the safety and efficacy of astemizole in the treatment of chronic idiopathic urticaria (more than or equal to 3 months). Seventeen male and 34 female adult patients with chronic idiopathic urticaria entered the 2-month study. After a 48- to 72-hour washout, half the subjects were prerandomized to receive astemizole (10 mg), and the other half received placebo. Placebo-treated patients who were unable to complete the full 8 weeks because of uncontrolled chronic urticaria symptoms were entered into a 2-month open astemizole trial. Treatment with astemizole, as measured at the end point of each patient's treatment and compared to placebo, resulted in significant improvement of pruritus, erythema, number of wheals, frequency of urticarial attacks, and control of urticaria (p less than or equal to 0.03). The overall response to astemizole was significantly better than for placebo, according to both the investigator's and the patient's global evaluations (p less than 0.01) and as indicated by dropouts caused by treatment failure with placebo (p = 0.005). Six of 26 (24%) of the placebo-treated patients in the double-blind study had good to excellent results on the basis of global assessments. Thirteen of 16 patients with placebo-treatment failures who received astemizole in the open trial improved significantly from baseline symptoms of pruritus, erythema, and number of wheals (p less than or equal to 0.05). No significant side effects were reported except mild sedation in three astemizole-treated subjects.(ABSTRACT TRUNCATED AT 250 WORDS)