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.

The addition of transdermal tulobuterol (Tulo) 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). 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 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 μg once daily, or combination therapy with Tio 18 μg once daily plus Tulo 2 mg once daily for 4 weeks. Patients then switched treatments for a further 4 weeks. 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. 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.