montelukast
Contents
Cysteinyl leukotriene receptor antagonist (CysLT1). Less effective than ICS for asthma control. Now carries an FDA boxed warning for neuropsychiatric adverse effects. Role limited to add-on therapy or when ICS is refused/not tolerated. Shared decision-making required before prescribing.
mechanism
Blocks CysLT1 receptor → reduces leukotriene-mediated bronchoconstriction, mucus secretion, oedema, and eosinophilic inflammation. Does not require inhalation — oral tablet.
dosing
| Age | Dose | Formulation |
|---|---|---|
| ≥ 15 years | 10 mg once daily (evening) | Tablet |
| 6–14 years | 5 mg once daily | Chewable tablet |
| 2–5 years | 4 mg once daily | Chewable tablet or granules |
No dose adjustment for renal or hepatic impairment. Evening dosing preferred (leukotriene levels peak overnight).
key points
- Inferior to low-dose ICS as monotherapy for asthma control and exacerbation prevention — should not be used as first-line controller
- Add-on role: may provide modest benefit when added to ICS at step 2–3, but less effective than adding a LABA (GINA 2024)
- Niche uses: exercise-induced bronchoconstriction (pre-exercise dosing), aspirin-exacerbated respiratory disease (eosinophilic lung disease), patients who refuse or cannot use inhalers
- Allergic rhinitis: approved for concurrent allergic rhinitis — may be useful in asthma patients with prominent nasal symptoms, though intranasal corticosteroids are more effective for rhinitis
- Variable response: ~50% of patients are “non-responders.” If no improvement in 4 weeks, discontinue rather than continue indefinitely
adverse effects
FDA boxed warning (2020): agitation, aggression, depression, suicidal ideation, hallucinations, sleep disturbance including nightmares. Risk applies to all ages. Counsel patients and caregivers before starting. Discontinue immediately if neuropsychiatric symptoms develop. Shared decision-making about risks vs benefits is mandatory (FDA 2020).
- Headache (most common)
- GI upset (abdominal pain, diarrhoea)
- Elevated transaminases (rare)
- Churg-Strauss-like syndrome (very rare — may unmask EGPA when OCS is reduced, rather than a direct drug effect)