Analysis of Neuropsychiatric Diagnoses After Montelukast Initiation.

IMPORTANCE: The evidence base for the association between montelukast and adverse neuropsychiatric outcomes is mixed and inconclusive. Several methodological limitations have been identified in the evidence base on the safety of montelukast in observational studies. OBJECTIVE: To investigate the association between new montelukast exposure and 1-year incident neuropsychiatric diagnoses with improved precision and control for baseline confounders. DESIGN, SETTING, AND PARTICIPANTS: This propensity score-matched cohort study was conducted using electronic health records from 2015 to 2019 in the TriNetX Analytics Network patient repository of more than 51 million patients from 56 health care organizations, mainly in the US. Included patients were those aged 15 to 64 years at index prescription for montelukast or for control prescription who had a history of asthma or allergic rhinitis. After propensity score matching for various baseline confounders, including comorbidities and dispensed prescription medicines, we included 154 946 patients, of whom 77 473 individuals were exposed to montelukast. Patients were followed up for 12 months. Data were analyzed from June through November 2021. EXPOSURES: New dispensed prescription for leukotriene receptor antagonist montelukast or control medication. MAIN OUTCOMES AND MEASURES: Incident neuropsychiatric diagnoses at 12 months identified using International Statistical Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes. RESULTS: There were 72 490 patients with asthma (44 726 [61.7%] women; mean [SD] age at index prescription, 35 [15] years) and 82 456 patients with allergic rhinitis (54 172 [65.7%] women; mean [SD] age at index prescription, 40 [14] years). In patients exposed to montelukast, the odds ratio [OR] for any incident neuropsychiatric outcome was 1.11 (95% CI, 1.04-1.19) in patients with asthma and 1.07 (95% CI, 1.01-1.14) in patients with allergic rhinitis compared with patients who were unexposed. The highest OR was for anxiety disorders (OR, 1.21; 95% CI, 1.05-1.20) among patients with asthma exposed to montelukast and insomnia (OR, 1.15; 95% CI, 1.05-1.27) among patients with allergic rhinitis exposed to montelukast. CONCLUSIONS AND RELEVANCE: This study found that patients with asthma or allergic rhinitis had increased odds of adverse neuropsychiatric outcomes after montelukast initiation. These findings suggest that clinicians should consider monitoring potential adverse mental health symptoms during montelukast treatment, particularly in individuals with a history of mental health or sleep problems.