Additive effects of transdermal tulobuterol to inhaled tiotropium in patients with COPD

SummaryBackgroundThe current mainstream treatment for COPD is bronchodilators alone or in combination. The effects of a β2-agonist, tulobuterol, administered transdermally, have been reported to last for 24 h. However, there are no reports on the efficacy of tulobuterol combined with an anticholinergic. In this study, we investigated the efficacy and safety of transdermal tulobuterol combined with inhaled tiotropium in COPD.MethodsAfter a 2-week run-in period, 103 stable COPD patients aged ≥40 years were randomized into two groups: inhaled tiotropium (18 μg, Tio group) or transdermal tulobuterol (2 mg) combined with inhaled tiotropium (18 μg, Tio + Tulo group) for 8 weeks. Primary endpoints were pulmonary function and severity of dyspnea. The St. George's Respiratory Questionaire (SGRQ) score was a secondary endpoint.ResultsIn both groups, FEV1 and FVC as well as dyspnea improved significantly after 8 weeks. In a comparison of both groups, percentage changes in IC and morning and evening peak expiratory flow were significantly greater in the Tio + Tulo group than in the Tio group. In addition, significant improvement in SGRQ score was observed in the Tio + Tulo group only. The risk of adverse events related to the study drugs was not increased.ConclusionIn COPD patients, additional administration of transdermal tulobuterol to inhaled tiotropium produced significant benefits in dyspnea and SGRQ score as well as pulmonary function. These benefits may be due to a reduction in pulmonary hyperinflation resulting from improvement of peripheral airflow obstruction through tulobuterol via the systemic circulation.