The purpose of this study was to determine the safety and effectiveness of albuterol aerosol 180 micrograms and albuterol powder 200 micrograms in the prevention of exercise-induced bronchospasm in children. Forty-six patients aged 4-11 years with asthma and exercise-induced bronchospasm were enrolled in this randomized, double-blind, single-dose, three-way crossover study comparing albuterol aerosol, albuterol powder, and placebo. Exercise challenge was performed at the screening visit for qualifying and baseline determinations of pulmonary function and then 15 min after drug administration at each of three visits. Prevention of exercise-induced bronchospasm was assessed by comparing across all treatment groups the percentage change in FEV1 from pre- to postexercise, the percentage of patients protected by treatment, postexercise minimum FEV1, and postexercise change in FEV1. Safety was assessed by observation of clinical adverse events, laboratory tests, physical examination, electrocardiogram and rhythm strips, vital signs, and pulmonary auscultation. Forty-four patients completed the study. Mean postexercise FEV1 decreased 6% from preexercise values when patients were treated with either albuterol formulation; FEV1 decreased 23% when patients were treated with placebo. Exercise-induced bronchospasm was prevented in 95% of patients when treated with albuterol powder, in 91% treated with albuterol aerosol, and in 57% treated with placebo. Patients maintained significantly higher mean minimum FEV1 values after treatment with albuterol powder and albuterol aerosol than when treated with placebo. Treatment with either albuterol formulation produced a significantly smaller decrease in mean FEV1 from pre- to postexercise than treatment with placebo. No drug-related adverse events were reported, and safety assessments were within normal limits.(ABSTRACT TRUNCATED AT 250 WORDS)