Inhaled atropine sulfate: dose-response characteristics in adult patients with chronic airflow obstruction.

Dose-response characteristics of inhaled atropine sulfate were examined in ten patients with chronic airflow obstruction using spirometric and plethysmographic measurements. Inhaled atropine in doses of 0.005, 0.01, 0.25, and 0.05 mg2kg of body weight and placebo were delivered by means of a precision metering device. All pulmonary function tests (FEV1, V50, and SGaw) improved progressively with increasing dose. There was a high degree of linear correlation between the peak response of each test and the logarithm of dose (r greater than or equal to 0.98). The highest dose studied (0.05 mg/kg) was found to have marginal benefit over 0.025 mg/kg, and had the highest incidence of adverse reactions. Duration of effect was dependent on dose. These results suggest that for adult patients with chronic airflow obstruction, 0.025 mg/kg delivered by a dosimeter approximates the optimally effective dose of inhaled atropine sulfate that can be given without unacceptable side effects.