Exercise-induced asthma. Pharmacological assessment of single drugs and drug combinations.

The relative effectiveness of ephedrine, theophylline, and hydroxyzine hydrochloride and their combinations was studied in a two-part investigation of 16 youths who has asthma and exercise-induced asthma. The beneficial and adverse effects of the drugs in the control of asthma were studied in the first part of the investigation. Both theophylline and ephedrine were judged superior to placebo when given alone. When combined they were somewhat more effective than either agent alone, although adverse effects precluded their use in almost half of the subjects. The addition of hydroxyzine diminished the side effects sufficiently to make the combination acceptable to four subjects who refused to take ephedrine/theophylline. In the second part of the study, the relief of exercise-induced asthma was evaluated. Ephedrine had no effect, hydroxyzine had a weak effect on hastening recovery, but theophylline modified the postexercise response significantly. The three drugs together produced an additive effect superior to that of theophylline alone.