The duration of bronchodilation of salmeterol and salbutamol as measured by specific airway conductance in healthy subjects.

According to the duration of bronchodilation, beta-2-agonists are divided into short and long acting bronchodilators. The bronchodilatory effect of available long acting beta-2-agonists (LABAs) beyond 12 h is not sufficiently studied. In order to evaluate the bronchodilatory effects of LABA in subjects without airway obstruction, the measurement of specific airway conductance (sGaw) with whole body plethysmography has been demonstrated to be a sensitive method. We aimed to determine the bronchodilatory effects of single doses of salmeterol 25, 50 and 200 μg and salbutamol 200 μg in healthy subjects (n = 16) over a 24 h period in a randomized, double-blind, triple-dummy, placebo-controlled cross-over-study. At the 12-h endpoint, all three doses of salmeterol significantly increased sGaw compared with placebo. At the 24-h endpoint, there was a significant increase in sGaw with salmeterol 200 μg, while with 25 and 50 μg salmeterol the sGaw increase failed to reach statistical significance. There was no statistically significant increase in sGaw with salbutamol 200 μg at either the 12-h or 24-h endpoints. For weighted means, all three salmeterol doses showed statistically significant increase in sGaw compared with placebo over 0-12, 12-24 and 0-24 h periods, while for salbutamol 200 μg a significant increase in sGaw was recorded only over 0-12 h period. We conclude that sGaw measurement is a suitable method for recording the bronchodilatory effect of beta-2-agonists in healthy subjects. Using this method we could demonstrate that salmeterol 200 μg provides significant increase in specific airway conductance up to 24 h after a single dose.

RCT Entities:   Population Interventions Outcomes