Double-blind comparison of astemizole and terfenadine in the treatment of chronic urticaria.

Two new non-sedating antihistamines, astemizole (10 mg per day) and terfenadine (120 mg per day), were compared in a double-blind randomized study in 42 adult patients suffering from chronic urticaria. The trial lasted 4 weeks. Patients were evaluated at 2 and 4 weeks and kept a daily diary of their symptoms. There was a statistically significant decrease in pruritus, erythema and urticaria papules in both groups throughout the study. Changes in papule size, number and frequency were greater in the astemizole group though not significantly different to the terfenadine group. The effect of astemizole increased with time whereas that of terfenadine decreased after about 3 weeks of treatment. Astemizole was globally considered to be the most effective drug by both investigator and patients, with excellent/good results in 77% of the patients compared with 55% to 60% in the terfenadine group. Both drugs were reported to be more effective and faster acting than other antihistamines taken previously. Side-effects were infrequent and minor in both groups.