A comparison of the bronchodilating effects of a beta-2 adrenergic agent (albuterol) and an anticholinergic agent (ipratropium bromide), given by aerosol alone or in sequence.

We evaluated the effect of anticholinergic and beta-adrenergic inhaled bronchodilators, alone or in sequence, in 11 patients with chronic obstructive pulmonary disease. We compared the agents albuterol and ipratropium bromide when each was used as a single aerosol in the maximal dose. After giving a maximal dose of one agent, we compared the effect of adding the other with that of adding a placebo. When used alone, both bronchodilators significantly increased airflow and relieved hyperinflation, and there was no significant difference between the two. After the improvement with the initial bronchodilator, the subsequent effect of a second inhaled bronchodilator was not greater than that of placebo. These results suggest that in the treatment of chronic obstructive pulmonary disease, these two aerosols are usually equipotent in maximal doses and the addition of a second agent is of no practical value. The data support the prescription of a single inhaled agent in most cases but do not rule out the value of combinations of agents under special circumstances.