Pharmacologic rationale underlying the therapeutic effects of tiotropium/olodaterol in COPD

Bronchodilators are the most important drugs used for the treatment of chronic obstructive pulmonary disease (COPD). In particular, these therapeutic agents are mostly long-acting compounds utilized via inhalation, and include LAMA (long-acting muscarinic receptor antagonists) and LABA (long-acting β(2)-adrenoceptor agonists). Because LAMA and LABA induce bronchodilation by distinct mechanisms of action, LABA/LAMA combinations provide a reciprocal potentiation of the pharmacological effects caused by each component. Hence, many COPD patients who do not achieve a satisfactory control of their symptoms using a single, either LAMA or LABA bronchodilator, can experience relevant benefits with the use of LAMA/LABA fixed combinations. Many different LAMA/LABA combinations have been recently developed and evaluated in randomized clinical trials. In this context, our review focuses on the pharmacological mechanisms underpinning the bronchodilation elicited by the LAMA tiotropium bromide and the LABA olodaterol. We also discuss the results of the most important clinical studies carried out in COPD patients to assess the efficacy and safety of tiotropium/olodaterol combinations.