Effect of inhaled atropine or metaproterenol in patients with chronic airway obstruction and therapeutic serum theophylline levels.

Twenty-one patients with stable chronic obstructive pulmonary disease (mean FEV1 = 0.98 L) and high-normal serum theophylline levels (15-20 micrograms/ml) were evaluated in a randomized, double-blind fashion for additional bronchodilator response to aerosolized normal saline, atropine, or metaproterenol. Patients were classified as responders (R; n = 9) or nonresponders (NR; n = 12) to inhaled isoproterenol when they were taking no medications. Atropine and metaproterenol caused a significant additional increase in FEV1 for R (p less than .05), whereas only atropine resulted in a significant increase for NR (p less than .05). For R, the increase due to atropine was significantly greater compared to metaproterenol (p less than .05). We conclude that inhaled atropine (an anticholinergic drug) may be preferable to inhaled metaproterenol (a beta-adrenergic agonist) when additional bronchodilation is needed in patients with chronic obstructive pulmonary disease and high-normal serum theophylline levels.