Comparison of formoterol, salbutamol and salmeterol in methacholine-induced severe bronchoconstriction

The onset of the bronchodilating effect of formoterol (12 mu g by Turbuhale r(R)) was compared with that of salbutamol (50 mu g by Turbuhaler), salmete rol (50 mu g by Diskhaler(R)) and placebo in methacholine-induced severe br onchoconstriction, Seventeen subjects with mild-to-moderate asthma completed this randomized, double blind, cross-over, double-dummy study. On four study days, baseline forced expiratory volume in one second (FEV1) was recorded and the subjects were challenged with methacholine until FEV1 fell by at least 30%, Immedia tely thereafter, the study drugs were inhaled and lung function was assesse d for 60 min, The geometric mean time for FEV1 to return to 85% of baseline was 7.2 min w ith formoterol, 6.5 min with salbutamol, 14.1 min with salmeterol and 34.7 min with placebo (p=0.0001, overall ANOVA). The difference between formoter ol and salmeterol was statistically significant (p=0.01); there was no diff erence between formoterol and salbutamol (p=0.69). In conclusion, formoterol reversed methacholine-induced severe bronchoconst riction as rapidly as salbutamol and more rapidly than salmeterol, Classify ing beta(2)-agonists as "fast"- and "slow"-acting may be supplemental to "s hort"- and "long"-acting.