montelukast
Leukotriene receptor antagonist· Brands: Singulair, Montair, Lukair, Monkasta, Quantair, MontizaPO
Mechanism of action
Montelukast is a selective leukotriene receptor antagonist that blocks the action of cysteinyl leukotrienes (LTC4, LTD4, LTE4) at the CysLT1 receptor. This reduces bronchoconstriction, inflammation, and mucus secretion in asthma and allergic rhinitis.
Pharmacokinetics
Montelukast is rapidly absorbed after oral administration, with peak plasma concentrations achieved in about 3 hours. It is highly protein-bound, extensively metabolised via cytochrome P450 enzymes (CYP3A4 and CYP2C9), and eliminated predominantly in bile. Its half-life is approximately 5 hours, allowing once-daily dosing.
Indications & dosing
Asthma (chronic treatment)
Administer in the evening.
- adult · PO: 10 mg once daily · Administer in the evening.
Asthma (chronic treatment)
For children 6 to 14 years; chewable tablet.
- pediatric · PO: 5 mg once daily · For children 6 to 14 years; chewable tablet.
Asthma (chronic treatment)
For children 2 to 5 years; chewable tablet or granules.
- pediatric · PO: 4 mg once daily · For children 2 to 5 years; chewable tablet or granules.
Asthma (chronic treatment)
For children 6 months to 2 years; granules.
- pediatric · PO: 4 mg once daily · For children 6 months to 2 years; granules.
Exercise-induced bronchoconstriction
Take at least 2 hours before exercise; do not exceed one dose daily.
- adult · PO: 10 mg PRN before exercise · Take at least 2 hours before exercise; do not exceed one dose daily.
Allergic rhinitis (seasonal and perennial)
May be taken with or without food.
- adult · PO: 10 mg once daily · May be taken with or without food.
Allergic rhinitis (seasonal and perennial)
For children 6 to 14 years; chewable tablet.
- pediatric · PO: 5 mg once daily · For children 6 to 14 years; chewable tablet.
Allergic rhinitis (seasonal and perennial)
For children 2 to 5 years; chewable tablet or granules.
- pediatric · PO: 4 mg once daily · For children 2 to 5 years; chewable tablet or granules.
Contraindications & precautions
- Hypersensitivity to montelukast or any of its excipients · Hypersensitivity reactions including anaphylaxis have been reported.
- Acute asthma attacks · Montelukast is not effective for acute attacks; use a rapid-acting beta2-agonist.
- Monitor for neuropsychiatric symptoms; discontinue if suicidal ideation or severe mood changes occur.
- Do not use as monotherapy for asthma; continue maintenance inhaled corticosteroids unless advised otherwise.
- Not intended for acute asthma attacks; always have a reliever inhaler available.
- Use with caution in patients with hepatic impairment; monitor liver function if needed.
- Use in pregnancy and breastfeeding only if clearly needed.
- In children and adolescents, observe for behavioural changes and psychiatric symptoms.
Adverse effects
- Headache
- Abdominal pain
- Upper respiratory tract infection
- Neuropsychiatric events (including suicidal ideation and depression)serious
- Hepatotoxicityserious
- Eosinophilic conditions (including Churg-Strauss syndrome)serious
Renal & hepatic adjustment
- Hepatic impairment (mild): No dose adjustment required.
- Hepatic impairment (moderate): No dose adjustment required; caution advised as limited data.
- Hepatic impairment (severe): Use with caution; consider alternative if severe hepatic impairment.
Monitoring, pregnancy & toxicity
- Respiratory symptoms (asthma control, exacerbations) · At each review
- Lung function (e.g., peak expiratory flow) · As clinically indicated
- Neuropsychiatric symptoms (mood, behaviour, suicidal ideation) · Regularly, especially after initiation or dose changes
- Pregnancy: Montelukast is not known to be harmful in pregnancy; animal studies do not show direct or indirect harmful effects. Use only if clearly needed, as data are limited.
- Toxicity: Symptoms of overdose can include abdominal pain, headache, vomiting, somnolence, thirst, and hyperactivity. · Treatment is supportive; empty stomach in recent ingestion if clinically appropriate, monitor vital signs, and manage symptoms. No specific antidote.
Clinical notes
Montelukast is used for maintenance treatment of asthma and for seasonal allergic rhinitis. It is not effective for acute asthma attacks. It may be used as an alternative to inhaled corticosteroids for mild asthma, but it is not a substitute for inhaled corticosteroids in moderate to severe asthma. Caution is advised in patients with neuropsychiatric symptoms, as montelukast has been associated with mood changes and behavioural effects. It is generally well tolerated, with headache and abdominal pain being common adverse effects.
Log in to read the full montelukast monograph
A free account unlocks the complete drug reference, the interaction checker, prescription practice and every other learning tool.
BNF; local formulary