Fenoterol in exercise-induced asthma. Effect of dose on efficacy and duration of action.

The effectiveness of inhaled fenoterol doses of 0.4 mg and 0.8 mg in preventing exercise-induced asthma was investigated in 12 patients. Exercise-induced asthma was prevented by both doses for two hours after administration, but the effect of neither dose was significantly different from that of placebo four hours after. There was no statistically significant difference between the effects of the two fenoterol doses; and only a few patients were protected for more than two hours by the higher dose.