Effectiveness of salmeterol versus ipratropium bromide on exertional dyspnoea in COPD

The hypothesis of the study was that salmeterol and ipratropium would have similar dyspnoea ratings during steady-state cycle ergometry at 1 h, but that salmeterol would reduce dyspnoea at 6 h after administration in patients with chronic obstructive pulmonary disease (COPD). The study design was a randomized, double-blind trial in 16 patients (aged 63 +/- 11 yrs) with symptomatic COPD. Two days after familiarization with testing procedures, patients were randomly assigned to receive either two puffs (42 microg) of salmeterol and two puffs of placebo inhaler, or two puffs (36 microg) of ipratropium from each of two inhalers (total, 72 microg). Two days later, patients received the alternative medication. During exercise at 60% of peak oxygen consumption patients rated dyspnoea and performed inspiratory capacity manoeuvres each minute. Forced expiratory volume in one second was 1.13+/-0.48 L (37+/-13% predicted). Dyspnoea ratings were similar for salmeterol and ipratropium at 1 and 6 h. Inspiratory capacity was similar for salmeterol and ipratropium at 1 h, but significantly higher for salmeterol at 6 h (delta = 120 mL; p = 0.03). It is concluded that with the doses used, salmeterol and ipratropium provided similar dyspnoea ratings during exercise at 1 and 6 h after administration.