The preventive effect and duration of action of nedocromil sodium and cromolyn sodium on exercise-induced asthma (EIA) in adults.

Nedocromil sodium, 4 mg, from a metered-dose inhaler, cromolyn sodium, (cr) 20 mg, from a Spinhaler, and placebo (pl) were compared in their efficacy and duration of action in preventing exercise-induced asthma. Twelve patients with asthma performed treadmill exercise tests 20 minutes, 2 hours, and 4 hours after a single dose of drug in a double-blind, crossover trial. Both active drugs were significantly better than pl at 20 minutes. Two hours after drug administration, only cr was significantly different from pl. The direct comparison between nedocromil and cr demonstrated no significant difference on FEV1, and the only significant difference was with forced expiratory flow between 25% and 75% of vital capacity at 2 hours. It is concluded that at these clinically recommended doses, both drugs are equally effective in preventing exercise-induced asthma with cr possibly having a somewhat longer duration of action.