Comparison of a B2 adrenergic agonist and an anticholinergic agent given by sequential inhalation in patients with severe chronic obstructive pulmonary disease.

We evaluated the response of 15 male patients with severe chronic obstructive pulmonary disease (COPD) to sequential inhalations of an anticholinergic agent, ipratropium bromide 0.25 mg (IB) and a B2 adrenergic agonist, terbutalin 2.5 mg (TER), in a double-blind crossover study. We found no statistically significant difference in the bronchodilatory response between the two agents when comparing the change in forced vital capacity and forced expiratory volume in 1 sec. The subsequent effect of the sequential inhalation demonstrated some additional bronchodilatory response when IB was given after TER, but not when TER was given after IB. However, the end result after the two protocols was not statistically different. The results indicate that in COPD patients the two agents are equipotent. However, in order to prescribe the best treatment schedule for each patient, it is still necessary to evaluate how each individual patient responds to each of the agents. Sequential inhalation may be beneficial in some patients.