Prevention of fog-induced bronchospasm by high doses of ipratropium bromide in asthmatics.

In 12 adult asymptomatic, relatively stable adult asthmatics the protective effect of 3 doses (200, 1,000 and 2,000 micrograms) of ipratropium bromide against bronchospasm induced by an ultrasonic mist of distilled water was functionally (sRaw, FEV1) assessed. Ipratropium bromide and placebo were administered as an inhalation powder via a special inhaler in random order and under double-blind conditions at the same time on 4 usually consecutive days 90 min prior to the challenge. A considerable protective effect (clearly inferior, in any case, to that previously observed by us with fenoterol) was demonstrated (% protection approximately equal to 50) without any striking difference among the 3 doses. Mouth dryness (dose-related) was the sole complaint in some patients.