Effect of ipratropium bromide on repeated methacholine challenges.

The purpose of this study was to trace the protective effect of ipratropium bromide (IB) during methacholine inhalation challenge (MIC) at the first and fourth hour after its administration. IB-inhaler contains 0.02 mg IB in each puff and it was used in the usual dosage of two puffs (0.04 mg). In 20 asthmatic patients, the dose of methacholine caused a drop in FEV1 of 20% (PD20-FEV1). It was concluded that IB protected patients significantly one hour after its administration and showed a significant bronchodilating effect in comparison to placebo. IB protected 19 of the 20 patients one hour after administration during MIC while placebo protected none. IB protected 13 of the 20 patients, after the second PD20-FEV1 with methacholine, four hours after its administration.