Effects of formoterol on exercise tolerance in severely disabled patients with COPD

Objective: We wished to evaluate the effects of inhaled formoterol, a tong-acting beta(2)-adrenergic agonist, on exercise tolerance and dynamic hyperinflation (DH) in severely disabled chronic obstructive pulmonary disease (COPD) patients. Design: In a two-period, crossover study, 21 patients with advanced COPD (FEV1 = 38.8 +/- 11.7% predicted, 16 patients GOLD stages III-IV) were randomly allocated to receive inhaled formoterol fumarate 12 mu g twice daily for 14 days followed by placebo for 14 days, or vice versa. Patients performed constant work-rate cardiopulmonary exercise tests to the Limit of tolerance (Tlim) on a cycle ergometer: inspiratory capacity (IC) was obtained at rest and each minute during exercise. Baseline and transitional dyspnoea indices (BDI and TDI) were also recorded. Results: Eighteen patients completed both treatment periods. Formoterol treatment was associated with an estimated increase of 130 s in Tlim compared with placebo (P = 0.052): this corresponded to a 37.8% improvement over placebo (P = 0.012). Enhanced exercise tolerance after bronchodilator was associated with diminished DH marked by higher inspiratory reserve and tidal volumes at isotime and exercise cessation (P < 0.05). There was no significant difference between formoterol and placebo on exercise dyspnoea rating; however, all domains of the TDI improved (P <= 0.02) following formoterol, compared with placebo. Conclusion: Inhaled formoterol 12 mu g twice daily is effective in ameliorating DH, daily dyspnoea and exercise intolerance even in patients with advanced COPD. (C) 2007 Elsevier Ltd. All rights reserved.