Montelukast use over the past 20 years: monitoring of its effects and safety issues.

Montelukast, a leukotriene receptor antagonist, was launched 20 years ago in Korea. It is recommended as an alternative treatment for asthma in children with mild persistent symptoms or as an add-on treatment to existing low-dose inhaled corticosteroids (ICSs) in children who require additional treatment. However, in the real-world setting, many doctors and patients prefer montelukast over ICSs despite their lower efficacy. Although montelukast is considered to be a safe drug, there are concerns regarding adverse drug reactions, including the rare occurrence of Churg-Strauss syndrome and, despite insufficient data, the possibility of neuropsychiatric events such as anxiety, depression, sleep disturbance, and suicidality. This review identified that montelukast has significantly contributed to asthma control over the past 20 years in Korea and has been critical for reducing asthma severity, especially early wheezing and disease control. Our findings suggest that the effects of montelukast treatment can be monitored by measuring serum eosinophilderived neurotoxin levels.