Abstract
Background Our objective was to determine the comparative bronchodilator, systemic beta(2)-agonist, cardiovascular and adverse effects of salbutamol 200 mu g and budesonide/formoterol 200/6 mu g when taken repeatedly in stable asthma.
Methods This open-label, crossover, single-centre, controlled trial randomised adults with asthma to different orders of two treatment regimens: salbutamol 200 mu g via metered-dose inhaler at 0, 30, 60 and 90 min, then salbutamol 2.5 mg via nebuliser at 120, 140, 160 and 420 min; or budesonide/formoterol 200/6 mu g one actuation via Turbuhaler at 0, 30, 60 and 90 min, then two actuations at 120, 140, 160 and 420 min. The primary outcome measure was forced expiratory volume in 1 s (FEV1) after 180 min. Secondary outcomes included repeat measures of FEV1, serum potassium, heart rate and adverse events.
Results Of 39 patients randomised, two withdrew due to adverse events (QT(CF )prolongation and T-wave abnormalities) after the first intervention with salbutamol. The mean +/- sd change from baseline FEV1 180 min after randomisation for salbutamol and budesonide/formoterol regimens was 0.71 +/- 0.46 L (n=38) and 0.58 +/- 0.45 L (n=37), respectively, with a mean +/- sd paired difference of -0.10 +/- 0.40 L (n=37) and a model-based estimated difference of -0.12 (95% CI -0.25-0.02) L (p=0.088). In the main secondary analysis, salbutamol resulted in significantly greater FEV1 from 30 to 240 min, but lesser FEV1 at 360 and 420 min. Salbutamol resulted in a significantly lower serum potassium, and a higher heart rate and number of adverse events.
Conclusions The comparative bronchodilator responses of repeated administration of salbutamol 200 mu g and budesonide/formoterol 200/6 mu g differed depending on the time of measurement. Salbutamol caused greater systemic beta(2)-agonist and cardiovascular effects and more adverse events.