Comparison of formoterol, salbutamol and salmeterol in methacholine-induced severe bronchoconstriction. M.J. Politiek, M. Boorsma, R. Aalbers. #ERS Journals Ltd 1999. ABSTRACT: The onset of the bronchodilating effect of formoterol (12 mg by Turbuhaler1) was compared with that of salbutamol (50 mg by Turbuhaler), salmeterol (50 mg by Diskhaler1) and placebo in methacholine-induced severe bronchoconstriction.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%. Immediately thereafter, the study drugs were inhaled and lung function was assessed for 60 min.The geometric mean time for FEV1 to return to 85% of baseline was 7.2 min with 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 formoterol and salmeterol was statistically significant (p=0.01); there was no difference between formoterol and salbutamol (p=0.69).In conclusion, formoterol reversed methacholine-induced severe bronchoconstriction as rapidly as salbutamol and more rapidly than salmeterol. Classifying b 2 -agonists as "fast"-and "slow"-acting may be supplemental to "short"-and "long"-acting. Eur Respir J 1999; 13: 988±992.

Virtually all asthma patients use brorichodilators. Formoterol and salbutamol have a rapid onset of bronchodilating effect, whereas salmeterol acts slower. We studied the onset of improvement of dyspnoea sensation after inhalation with these bronchodilators and placebo to reverse a methacholine-induced bronchoconstriction as a model for an acute asthma attack. Seventeen patients with asthma completed this randomised, double-blind, crossover, double-dummy study. On 4 test days, forced expiratory volume in 1 s (FEV1) and Borg score were recorded and patients were challenged with methacholine until FEV1 fell with > or = 30% of baseline value. Thereafter, formoterol 12 microg via Turbuhaler, salbutamol 50 microg via Turbuhaler, salmeterol 50 microg via Diskhaler, or placebo was inhaled. FEV1 and Borg scores were assessed during the following 60 min. The first sensed improvement of Borg score was significantly (P<0.05) faster achieved with formoterol (geometric mean (Gmean) (range) 1.5 (1-40) min) and salbutamol 1.8 (1-10) min than with salmeterol 4.5 (1-30) min and placebo 3.4 (1-40) min. The Borg score returned significantly faster to the baseline value with formoterol, salbutamol, and salmeterol (Gmean time 13.8 (1-75), 13.4 (1-60), and 18.0 (1-75) min, respectively) than with placebo (33.6 (1-75 min). Formoterol and salbutamol act significantly faster than salmeterol in relieving dyspnoea induced by methacholine-induced bronchoconstriction, in patients with asthma.

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