Double-blind, cross-over study of cromolyn sodium inhibition of exercise-induced bronchospasm in adults.

Twelve asthmatic subjects with exercise-induced bronchospasm (EIB) were studied during two initial and one final control period as well as after placebo lactose and 20 mg cromolyn sodium administered 15 minutes before treadmill exercise. During exercise the heart rate was maintained at approximately 80% of the age-adjusted predicted maximum. The mean FEV1 in the 12 subjects decreased 40% and 33% after exercise during control periods, 28% with placebo treatment and 13% after cromolyn sodium. Placebo was associated with 25% and cromolyn sodium with 67% protection of FEV1 (P less than 0.005). Similar effects were noted on FVC and MMF measurements. Cromolyn sodium appeared to decrease EIB in seven of the 12 asthmatic patients. The results of this study suggest that cromolyn sodium is effective in some adult patients with EIB.