Use of serial exercise tests to assess the efficacy and duration of action of drugs for asthma.

, , 574-578. A technique for studying the efficacy and duration of action of drugs used in asthma by means of exercise tests is described. The patient runs for six minutes every two hours, four times a day, on a treadmill at a constant speed and slope. The test drug or its placebo is given immediately before the first test of the day, and their effects on the exercise-induced asthma are compared. This enables the immediate protection and duration of action of the test drug to be measured. No change in the severity of post-exercise asthma was found when serial tests were performed during one day after administration of a placebo. In a selected group of 14 children studied with disodium cromoglycate, three patterns were seen. In five patients the drug afforded prolonged benefit, in five others the protection was very short-lived, and in four patients it did not seem to be better than the placebo. The use of the tests is also illustrated with respect to bronchodilator drugs.