Suppression of exercise-induced asthma by salbutamol, theophylline, atropine, cromolyn, and placebo in a group of asthmatic children.

A number of drugs are known to inhibit exercise-induced asthma (EIA), but the results in some cases have been difficult to interpret due to the techniques employed. A comparative study was carried out in a group of children to investigate the effects of salbutamol, choline theophyllinate, cromolyn sodium, atropine, and placebo. The exercise test took the form of six minutes of standardized treadmill running. All the drugs, but not the placebo, were able to inhibit EIA ti a significant degree, the effect being most marked with salbutamol. Cromolyn sodium caused no bronchodilatation at rest, while all the other drugs were brondhocilators, the effect being most marked with the atropine during exercise. It was impossible to distinguish the type of drug used for inhibition of EIA if it caused bronchodilatation at rest. The manner in which an exercise test can be used to investigate the duration of action or site of action of drugs is noted.