The 24 h duration of bronchodilator action of the budesonide/formoterol combination inhaler.

INTRODUCTION: The duration of bronchodilator action of the long-acting beta-agonist formoterol when administered in the evening has not been investigated. In this study we have investigated whether a single evening dose of formoterol, administered from the combination budesonide/formoterol (BUD/F) Turbuhaler significantly attenuates the circadian rhythm in airway tone over 24 h. METHODS: Twenty subjects with mild to moderate asthma (mean FEV1 84% predicted) participated in a double-blind, placebo-controlled, cross-over study. Subjects inhaled, in random order, placebo or BUD/F (2x100/6 microg) administered in the evening (2000 h) on two separate occasions. Lung function measurements including FEV1, specific airways conductance (sGaw) and maximum expiratory flow at 25-75% of vital capacity (MEF(25-75%)) were assessed at baseline, at 1 h and subsequently every 4 h post-dose for 24 h. RESULTS: Compared with placebo, BUD/F significantly improved the three measures of airways function throughout the 24 h period, with a difference in FEV1 at 24 h of 0.20L (0.04-0.35L). BUD/F attenuated the biphasic pattern of the circadian rhythm in airway tone. CONCLUSION: The single evening administration of formoterol from the combination BUD/F inhaler resulted in a duration of bronchodilation of at least 24 h.