The effect of inhaled tiotropium bromide on lung mucociliary clearance in patients with COPD.

STUDY OBJECTIVE To assess the effects of tiotropium on lung mucociliary clearance in COPD. DESIGN Randomized, double-blind, placebo-controlled, parallel-group study. SETTING Outpatients of an urban-area university teaching hospital. PATIENTS Thirty-four patients with COPD aged 40 to 75 years classified equally into two groups. INTERVENTION Single (18 microg) daily dose of tiotropium inhalation capsules or of placebo for 21 days. METHODS Six-hour tracheobronchial clearance of inhaled 99mTc-labeled polystyrene particles using a 48-h retention measurement to determine the "nontracheobronchial" deposition fraction. RESULTS Test radioaerosol penetration into the lungs increased significantly (p < 0.003) as did FEV1 (p < 0.006) in the tiotropium-treated patients, but measured mucociliary clearance was not significantly changed despite the increased pathway length for clearance (mean +/- SE area under the tracheobronchial retention curve changed from 442 +/- 22 to 453 +/- 20%/h). Smaller (nonsignificant) decreases of radioaerosol penetration and FEV1 occurred in the placebo group together with a small (nonsignificant) decrease in the area under the retention curve. CONCLUSION Twenty-one days of inhaled tiotropium, 18 microg/d, as a dry powder does not retard mucus clearance from the lungs.