American Review of Respiratory Disease

The recent development of new β2-adrenoceptor agonists with a duration of action in excess of 12 h may change strategies in the treatment of bronchial asthma. This study aims at the direct comparison of the main representatives of this new class of drugs, formoterol (F) and salmeterol (S), in asthmatic patients over the course of 24 h. Twelve patients with mild bronchial asthma participated in a double-blind, randomized, placebo-controlled clinical trial. In a dose-finding study we determined the protective and bronchodilating effects of 12 and 24 µg F aerosol vs 50 and 100 µg S 30 min after inhalation. In a 24-h study we investigated the effects of 12 µg F and 50 µg S on airway tone and responsiveness. Bronchial responsiveness was assessed as the dose of methacholine necessary to decrease FEV1 by 20%. In the dose-finding study, compared with placebo, all doses of F and S equally increased FEV1 (p < 0.003) and protected against inhaled methacholine (p < 0.0001). In the 24-h study 12 µg F and 50 µg S increased FEV1 and significantly protected against methacholine-induced bronchoconstriction up to 24 h (p < 0.05), compared with placebo. Phase and amplitude of the circadian variation of FEV1 and airway responsiveness were not affected. Clinically recommended doses of aerosolized F (12 µg) and S (50 µg) have a duration of action up to 24 h and are equally effective at bronchodilation and protection in acute experiments in patients with mild bronchial asthma.


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