Aspirin and methacholine challenges in an ambulatory asthmatic population.

Twenty-one low-risk outpatient asthmatics were challenged with 650 mg. of aspirin (ASA) and placebo in a double-blind manner. Methacholine dose response curves were performed after both aspirin and placebo administration. Baseline FEV1 was similar before aspirin and placebo challenges. No adverse clinical reactions were noted. No patient had a positive ASA challenge with a greater than 20% decrease in FEV1. Aspirin had no effect on bronchial reactivity that could be measured by a change in methacholine responsiveness.