Leukotriene receptor antagonists · Respiratory
Montelukast
Singulair®(brand names vary by market)
A tablet for asthma, with a warning most patients are never given.
Also: oral liquid
Mechanism
Cysteinyl leukotriene receptor antagonist: blocks the bronchoconstriction, mucus secretion and eosinophil recruitment driven by the leukotriene arm of arachidonic acid metabolism.
Indications
- Asthma, as add-on controller
- Exercise-induced bronchoconstriction
- Allergic rhinitis
- Aspirin-exacerbated respiratory disease
Formulations
Dosing concepts
Add-on, not replacement
It is weaker than an inhaled corticosteroid and does not replace one in persistent asthma.
Timing
Taken in the evening, which suits the nocturnal pattern of asthma symptoms.
Concepts, not prescribing instructions. Practice numbers live in current references and local protocols.
Pharmacokinetics
- Bioavailability
- ~64%
- Half-life
- 2.7 to 5.5 h
- Elimination
- hepatic: CYP2C8 and 3A4; biliary excretion
- Protein binding
- >99%
Adverse effects
- Headachecommon
- Neuropsychiatric eventsseriousAgitation, aggression, nightmares, depression and suicidality. A boxed warning in several jurisdictions and disproportionately reported in children.
- Abdominal paincommon
Contraindications & precautions
Contraindications
- Not for acute bronchospasm
Precautions
- Existing psychiatric illness
- Children and adolescents
Interactions
No curated interaction entries yet for this agent.
Monitoring
Mood, sleep and behaviour
The neuropsychiatric warning, which is routinely not passed on · Ask at every review, and ask the parent
Asthma control
If it is not helping after a fair trial, stop it
Counselling points
- Take it in the evening.
- It is a preventer, not a reliever.
- Tell us straight away about changes in mood, sleep, nightmares, or unusual behaviour. This is a recognised effect and a reason to stop.
- Parents: watch for irritability, low mood or aggression in a child taking this.
Clinical pearls
- The neuropsychiatric warning is the single most important counselling point for this drug and the one most often omitted. Families frequently only connect the symptoms after it is raised.
- It genuinely shines in aspirin-exacerbated respiratory disease and in exercise-induced symptoms, where the mechanism matches the trigger.
References & review
- Montelukast product monograph (consult the current version for your market) (monograph)
- Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed. (reference-work)
Last reviewed 2026-08-16 · jurisdiction: global · drug information changes; verify against current references before practice use.