Effects of inhaled tiotropium plus transdermal tulobuterol versus tiotropium alone on impulse oscillation system (IOS)-assessed measures of peripheral airway resistance and reactance, lung function and quality of life in patients with COPD: A randomized crossover study

Background: The addition of transdermal tulobuterol (Tub) to inhaled tiotropium bromide (Tio) produced beneficial effects on spirometry-assessed parameters of respiratory function, disease-related symptoms and quality of life in patients with chronic obstructive pulmonary disease (COPD). Aim: To compare the effects of Tio plus Tulo versus Tio alone on peripheral airway obstruction and quality of life in Japanese patients with COPD using impulse oscillation system (IOS)-assessed measures. Patients and methods: Patients aged 50-80 years with clinically stable COPD and a forced expiratory volume in 1 s (FEV(1)) that was 30-80% of the predicted value were randomized to receive Tio 18 mu g once daily, or combination therapy with Tio 18 mu g once daily plus Tulo 2 mg once daily for 4 weeks. Patients then switched treatments for a further 4 weeks. Results: Sixteen patients completed the study. Tio plus Tulo was associated with significantly greater improvements than Tio in IOS-assessed markers of resistance (R5 and R5-R20), reactance and reactance area, from baseline to week 4. Both treatments significantly improved these markers over the 4-week treatment period, with the exception of R20 for which improvements were not significant. Tio plus Tulo improved symptoms of dyspnea to a significantly greater extent than Tio alone. St. George's Respiratory Questionnaire Score-Total was not significantly different between the two groups, but improvement from baseline in the 'impact' component was significantly greater with Tio plus Tulo than with Tio alone. Conclusions: Coadministration of transdermal Tulo with inhaled Tio, as well as Tio alone, is associated with beneficial effects on IOS-assessed measures of peripheral airway obstruction in patients with COPD. (C) 2011 Elsevier Ltd. All rights reserved.