Montelukast: Leukotriene Receptor Antagonist for Asthma and Allergic Rhinitis
Montelukast (Singulair) is a selective, competitive antagonist of the cysteinyl leukotriene type 1 (CysLT1) receptor, blocking the effects of leukotrienes (LTC4, LTD4, LTE4) — potent inflammatory mediators released from mast cells and eosinophils.
Approved for asthma (persistent, as add-on to ICS), seasonal and perennial allergic rhinitis. Important note: FDA (2020) and EMA added neuropsychiatric warnings — mood changes, suicidal thoughts reported.
Mechanism of Action
Blocks CysLT1 receptors in airways and nasal mucosa, reducing bronchoconstriction, mucus secretion, and eosinophil recruitment. Does not bronchodilate acutely — not for rescue use. Complementary mechanism to ICS (targets leukotrienes rather than corticosteroid pathway).
Indications & Use
Mild-to-moderate persistent asthma (add-on to ICS, or alternative for ICS-intolerant patients), allergic rhinitis (seasonal and perennial — including combined asthma+rhinitis). Exercise-induced bronchoconstriction (preventive). Age ≥6 months (chewable tablet, granules formulations available).
Dosage
Adults and adolescents ≥15 years: 10 mg once daily (evening). Children 6–14 years: 5 mg (chewable) once daily. Children 2–5 years: 4 mg once daily. Children 6 months–2 years: 4 mg granules. Take in the evening for asthma.
Side Effects
Common: headache, abdominal pain, nausea, fatigue. Important: neuropsychiatric effects — agitation, aggression, anxiety, depression, hallucinations, suicidal ideation (FDA/EMA black box warning, 2020). Rarely: Churg-Strauss syndrome (as corticosteroids are tapered).
Drug Interactions
CYP inducers (rifampicin, phenytoin): reduce montelukast levels — monitor asthma control. Phenobarbital: similar. Generally few pharmacokinetic interactions.
Contraindications
Hypersensitivity. Not for acute asthma attacks. Caution in patients with history of psychiatric disorders. Do not use for aspirin/NSAID-exacerbated asthma as primary treatment.
Frequently Asked Questions
What are the neuropsychiatric risks of montelukast?
In 2020, the FDA added a black box warning for montelukast: reported neuropsychiatric events include agitation, aggression, anxiety, depression, insomnia, sleep disturbances, hallucinations, and suicidal ideation/behaviour. These can occur at any age. Discontinue if such symptoms develop.
Should montelukast be taken in the morning or evening?
For asthma, evening dosing (1 hour before sleep) is recommended as leukotrienes peak during sleep and early morning hours. For rhinitis only, timing is less critical.
Is montelukast as effective as ICS for asthma?
No. Inhaled corticosteroids (ICS) remain the gold standard for persistent asthma. Montelukast is add-on therapy or used when ICS is not tolerated. Combining both (ICS + montelukast) can offer additive benefits, especially in patients with allergic rhinitis.
References
- FDA Safety Communication Montelukast 2020
- GINA Asthma Report 2023
- EMA Singulair SPC 2023
Medical Disclaimer: This information is for educational purposes only and does not replace professional medical advice.