ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
Bronchodilator Pregnancy: B — limited data; benefit-risk assessment required

Montelukast

Brand names: Singulair

Adult dose

Dose: 10mg OD
Route: Oral
Frequency: Once daily (evening)
Max: 10mg/day
Asthma add-on therapy. Also indicated for allergic rhinitis and exercise-induced bronchospasm. Take in the evening.

Paediatric dose

Route: Oral
Frequency: Once daily (evening)
Max: 10mg
Age bands
  • 12–24m: 4mg granules OD (chew/dissolve)
  • 24–72m: 4mg chewable tablet OD
  • 72–180m: 5mg chewable tablet OD
  • 180–216m: 10mg film-coated tablet OD
Fixed-dose by age, not weight-based (per BNFc). 6 months–5 years: 4 mg OD (granules or chewable). 6–14 years: 5 mg OD (chewable). ≥15 years: 10 mg OD.

Clinical pearls

  • FDA black box warning (2020): neuropsychiatric events including suicidal ideation. Counsel patients and carers before prescribing. Review regularly.
  • Most useful for aspirin-exacerbated respiratory disease (Samter's triad) and exercise-induced bronchoconstriction.
  • Less effective than ICS for asthma control — step up ICS before adding montelukast as add-on.
  • Can be prescribed for allergic rhinitis (4 weeks initial) in children >6 months — NICE approved.

Contraindications

  • Hypersensitivity to montelukast

Side effects

  • Neuropsychiatric effects: nightmares, insomnia, anxiety, depression, suicidal ideation — FDA black box warning
  • Headache
  • GI disturbance
  • Elevated liver enzymes (rare)

Interactions

  • Phenobarbital / rifampicin: reduce montelukast levels (CYP3A4 induction)

Monitoring

  • Asthma control (symptom diary
  • peak flow)
  • neuropsychiatric symptoms at each review

Reference: BNFc; NICE NG80 Asthma; MHRA Montelukast Safety Alert 2022; NICE BNF 84. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Drugs
Pathways