Comparison of the bronchodilator activities of oxitropium bromide, fenoterol, and their combination in patients with chronic obstructive pulmonary disease and bronchial asthma.

The effects of an antimuscarinic agent, oxitropium bromide (200 micrograms), a beta-2 adrenoceptor agonist, fenoterol (200 micrograms), and their combination, were compared in ten patients with chronic obstructive pulmonary disease and ten patients with bronchial asthma, in a placebo-controlled, single blind crossover trial. In patients with chronic obstructive pulmonary disease, oxitropium and fenoterol produced a significant and similar degree of bronchodilatation. The duration of the bronchodilator effect was 3 h after oxitropium and 4 h after fenoterol, respectively. The combination of oxitropium and fenoterol produced a significantly greater degree of bronchodilatation than either drug alone. The duration of bronchodilatation in combination was 7 h and was considerably longer than that of each drug alone. In patients with bronchial asthma, oxitropium and fenoterol also caused bronchodilatation. Their combination produced a significantly greater degree of bronchodilatation than when either drug was used. The duration of the bronchodilator effects were 5 h after oxitropium, 4 h after fenoterol and 5 h after the combination. We conclude that the combination of oxitropium and fenoterol causes greater bronchodilatation in patients with chronic obstructive pulmonary disease and bronchial asthma than when compared to each drug alone. In the former, the duration of bronchodilatation is additionally prolonged. These combination effects may be of value in the clinical management of these common respiratory disorders.