Exercise-induced asthma: comparison of cromoglycate powder and aerosol four hours before exercise.

To establish whether sodium cromoglycate delivered by pressurised aerosol was more effective than sodium cromoglycate powder in preventing exercise-induced asthma four hours after drug administration, eight subjects known to be protected by sodium cromoglycate taken immediately pre-exercise, underwent delayed exercise challenge following double-blind premedication with sodium cromoglycate powder, sodium cromoglycate aerosol and placebo. The maximum fall in FEV1 induced by exercise four hours after inhaling sodium cromoglycate was modified slightly by sodium cromoglycate powder and by a smaller amount, sodium cromoglycate aerosol, compared with the unpremedicated run, but the calculated protection provided by sodium cromoglycate was not significantly different from that given by placebo. It was concluded that asthmatics should not expect significant suppression of exercise-induced bronchoconstriction four hours after the last dose of either cromoglycate powder or aerosol.