Combined cholinergic antagonist and beta 2-adrenoceptor agonist bronchodilator therapy by inhalation

The bronchodilator effects of 40 microgram ipratropium bromide (I) and 400 microgram fenoterol (F) by pressurised aerosol and both drugs in combination were compared with placebo (P) in a double-blind study in eight patients with chronic, partially reversible airways obstruction. The four treatments were (1) IP, (2) PF, (3) IF and (4) PP, with the second aerosol administered two hours after the first. Both drugs produced significant bronchodilatation for five hours, the response being greater and more rapid in onset with fenoterol. Both drugs in combination (IF) produced significant additive bronchodilatation from three to six hours after fenoterol. This additive effect may have been due to the improved lung function caused by ipratropium bromide and does not imply a synergistic effect. There were no side-effects reported. The results suggest that both ipratropium bromide and fenoterol are effective bronchodilating agents in patients with chronic asthma.