Effects of formoterol in apparently poorly reversible chronic obstructive pulmonary disease

This randomized, double-blind, placebo-controlled, crossover study was designed to investigate the effects of the long-acting beta2-adrenoreceptor agonist formoterol fumarate in 12 current or exsmokers having chronic obstructive pulmonary disease, with a mean forced expiratory volume in one second (FEV1) 47% of predicted, poorly reversible (5.1% pred) after terbutaline sulphate inhalation. After inhaling a single dose of formoterol (6 or 24 microg), or placebo via Turbuhaler, FEV1 and pulmonary function parameters measured during quiet breathing (work of breathing (WoB) and airway resistance (Raw)) were recorded over 12 h on three test days. Immediate changes in FEV1 were modest, although each dose of formoterol caused a response >12% pred within 10 min in one subject. Compared to placebo, both doses of formoterol induced a clinically and statistically relevant improvement in WoB (>25%) and Raw (>20%), which occurred within 10 min and lasted over a period of 12 h (p < or = 0.02, analysis of variance). Thus, inhaled formoterol causes long-lasting lung functional improvements in apparently poorly reversible chronic obstructive pulmonary disease. Additional lung function measurements during quiet breathing after forced expiration tests may be useful in such patients to assess beneficial effects of bronchodilators.