Bronchodilators remain the cornerstone of the treatment of airway disorders such as asthma and chronic obstructive pulmonary disease (COPD). There is therefore considerable interest in understanding how to optimize the use of our existing classes of bronchodilator and in identifying novel classes of bronchodilator drugs. However, new classes of bronchodilator have proved challenging to develop because many of these have no better efficacy than existing classes of bronchodilator and often have unacceptable safety profiles. Recent research has shown that optimization of bronchodilation occurs when both arms of the autonomic nervous system are affected through antagonism of muscarinic receptors to reduce the influence of parasympathetic innervation of the lung and through stimulation of β 2-adrenoceptors (β 2-ARs) on airway smooth muscle with β 2-AR-selective agonists to mimic the sympathetic influence on the lung. This is currently achieved by use of fixed-dose combinations of inhaled long-acting β 2-adrenoceptor agonists (LABAs) and long-acting muscarinic acetylcholine receptor antagonists (LAMAs). Due to the distinct mechanisms of action of LAMAs and LABAs, the additive/synergistic effects of using these drug classes together has been extensively investigated. More recently, so-called "triple inhalers" containing fixed-dose combinations of both classes of bronchodilator (dual bronchodilation) and an inhaled corticosteroid in the same inhaler have been developed. Furthermore, a number of so-called "bifunctional drugs" having two different primary pharmacological actions in the same molecule are under development. This review discusses recent advancements in knowledge on bronchodilators and bifunctional drugs for the treatment of asthma and COPD. SIGNIFICANCE STATEMENT: Since our last review in 2012, there has been considerable research to identify novel classes of bronchodilator drugs, to further understand how to optimize the use of the existing classes of bronchodilator, and to better understand the role of bifunctional drugs in the treatment of asthma and chronic obstructive pulmonary disease.

中文翻译：

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再次探讨了支气管扩张药的药理学和治疗学。

支气管扩张剂仍然是治疗气道疾病（例如哮喘和慢性阻塞性肺疾病（COPD））的基石。因此，人们非常有兴趣了解如何最有效地使用我们现有的支气管扩张剂，并确定新型的支气管扩张药。然而，事实证明，开发新型的支气管扩张剂具有挑战性，因为许多此类支气管扩张剂的疗效均不比现有的支气管扩张剂好，而且安全性常不可接受。最近的研究表明，当自主神经系统的两臂受到毒蕈碱受体的拮抗作用以减少肺副交感神经支配的影响以及通过刺激气道中的β2-肾上腺素能受体（β2-ARs）来影响支气管扩张时，就会发生支气管扩张的优化。 β2-AR选择性激动剂模拟平滑肌对肺的交感影响。目前，这是通过使用吸入的长效β2-肾上腺素受体激动剂（LABAs）和长效毒蕈碱型乙酰胆碱受体拮抗剂（LAMAs）的固定剂量组合来实现的。由于LAMA和LABA的独特作用机理，广泛研究了一起使用这些药物类别的累加/协同作用。最近，所谓的“三重吸入器” 已经开发出在同一吸入器中含有两种类型的支气管扩张剂（双重支气管扩张剂）和吸入皮质类固醇固定剂量组合的药物。此外，正在开发在同一分子中具有两种不同的主要药理作用的许多所谓的“双功能药物”。这篇综述讨论了支气管扩张药和双功能药物治疗哮喘和COPD知识的最新进展。重大声明：自2012年进行最后一次审查以来，已经进行了大量研究，以识别新型的支气管扩张药，进一步了解如何优化现有类型的支气管扩张药的使用，并更好地了解双功能药物在治疗中的作用哮喘和慢性阻塞性肺疾病。