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Leukotriene Receptor Antagonist — Allergic Rhinitis Pregnancy: Use with caution — limited data; avoid unless clearly indicated; continue if benefits outweigh risks in severe asthma

Montelukast

Brand names: Singulair

Adult dose

Dose: 10 mg once daily at bedtime
Route: Oral
Frequency: Once daily at bedtime
Max: 10 mg/day
Used as adjunct therapy for allergic rhinitis (especially when asthma co-exists), nasal polyp management, and NSAID-exacerbated respiratory disease. Less effective than intranasal corticosteroids as monotherapy — usually combined. BTS/SIGN and BSACI recommend as add-on to ICS for asthma + AR.

Paediatric dose

Dose: Age-based mg/kg
Route: Oral
Frequency: Once daily at bedtime
Max: 10 mg/day (adults and children ≥15 years)
BNFc: 6 months–5 years 4 mg granules or chewable tablet; 6–14 years 5 mg chewable tablet; ≥15 years 10 mg tablet. Granules can be mixed with food.

Dose adjustments

Renal

No dose adjustment required

Hepatic

Use with caution in severe hepatic impairment

Paediatric weight-based calculator

BNFc: 6 months–5 years 4 mg granules or chewable tablet; 6–14 years 5 mg chewable tablet; ≥15 years 10 mg tablet. Granules can be mixed with food.

Clinical pearls

  • MHRA 2019: serious neuropsychiatric effects including suicidal ideation, sleep disturbances, aggression — inform patients and carers; stop immediately if neuropsychiatric symptoms emerge
  • MHRA 2020: black box warning added in US (FDA) for neuropsychiatric risk — consider benefit vs risk before prescribing, especially in children
  • Most effective for AR with asthma comorbidity — LTRAs reduce both lower and upper airway inflammation simultaneously
  • NSAID-exacerbated respiratory disease (AERD/Samter's triad): aspirin sensitivity + asthma + nasal polyps — montelukast reduces polyp recurrence post-surgery
  • Less effective than intranasal steroids for nasal symptoms when used alone — use as adjunct
  • Counselling on neuropsychiatric risks is mandatory at initiation — document in notes

Contraindications

  • Hypersensitivity to montelukast
  • Active psychiatric illness (relative — MHRA warning)

Side effects

  • Neuropsychiatric effects (agitation, aggression, suicidal ideation, depression — MHRA 2019 black box)
  • Headache
  • GI disturbance
  • Rash (rare)
  • Upper respiratory tract infections

Interactions

  • Phenobarbital, rifampicin — reduce montelukast levels (CYP inducers)
  • Gemfibrozil — increase montelukast levels

Monitoring

  • Neuropsychiatric symptoms (agitation, depression, sleep disturbance)
  • Asthma control
  • Nasal symptom score

Reference: BNFc; BNF 90; BNFc; MHRA Drug Safety Update (2019 and 2020) Montelukast; BSACI Rhinitis Guidelines 2017. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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