Effect of age on bronchodilator response.

STUDY OBJECTIVE Our objective was to compare the differential effects of age and drug type on bronchodilator response. DESIGN The design was an unblinded, randomized crossover study. SETTING An ambulatory pulmonary drug study unit was the setting. PATIENTS Nineteen young (18 to 25 yr) and 17 elderly (greater than 65 yr) stable asthmatic subjects were studied. INTERVENTIONS AND MEASUREMENTS Albuterol or ipratropium was given on two separate mornings using an MDI with extender. Subjects inhaled two puffs initially and then one puff every 30 min to a total of six puffs. Pulmonary function, blood pressure, and pulse were measured at baseline and every 30 min for 3 h. RESULTS All subjects had a greater than 15 percent increase in FEV1 with one or both drugs. More patients responded to albuterol than to ipratropium in both age groups. The maximum percentage of change from baseline was greater (p less than 0.05) with albuterol (mean, 40.1 percent in young and 60.5 percent in old) than with ipratropium (21.2 percent in young; 31.2 percent in old) in both groups. These differences remain significant after correction for baseline differences using area-under-the-curve analysis of the percent of maximum improvement; however, the differences between age groups for the same drug were not statistically significant by either index of change. There were also no differences between drugs or between age groups for time (or number of puffs) to reach maximum improvement (mean, 2.0 to 2.2 h for albuterol and 1.6 to 1.7 h for ipratropium). The changes in FVC and FEF25-75% were similar to FEV1. Changes in blood pressure and pulse were not significant. Three subjects stopped therapy with albuterol with side effects. CONCLUSIONS Both drugs are effective bronchodilators in young and old asthmatic subjects, but albuterol results in a greater magnitude of response in both age groups. Age is not a predictor of response to either drug.