Understanding the role of long-acting muscarinic antagonists in asthma treatment

Objective: Long-acting muscarinic antagonists (LAMAs) have been used in the treatment of obstructive pulmonary diseases for years. Long-acting muscarinic antagonists were previously mainly used as bronchodilators in chronic obstructive pulmonary disease, but the use of LAMAs in the treatment of asthma has gained great interest. There is now ample evidence of the efficacy and safety of LAMAs as add-on therapy to inhaled corticosteroid (ICS) plus long-acting β 2-agonist (LABA) combinations in patients with moderate to severe uncontrolled asthma. Long-acting muscarinic antagonists have subsequently been included in asthma guidelines. This review summarizes the scientific evidence on the use of LAMAs in asthma and aims to provide a better understanding of the role of LAMAs in the asthma treatment care algorithm and the current gaps in our knowledge. Data sources: PubMed review using the following words: long-acting muscarinic antagonists, asthma, muscarinic receptors, tiotropium, glycopyrronium, umeclidinium. Study selections: This review focused on the key trials that led to the inclusion of LAMAs in asthma guidelines. In addition, we highlighted a number of studies with other study designs and populations. Results: We identified 6 major studies that led to inclusion in asthma guidelines and 3 studies with other study designs and populations. Conclusion: Long-acting muscarinic antagonists add-on therapy to ICS-LABA improves lung function, reduces exacerbations, and modestly improves asthma control in patients with moderate to severe asthma who are uncontrolled despite the use of ICS-LABA. Long-acting muscarinic antagonists are effective in all asthma phenotypes and endotypes.