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Leukotriene Receptor Antagonist — Allergic Rhinitis

Montelukast

Brand names: Singulair

Used in: Asthma

Montelukast is a leukotriene receptor antagonist used as add-on preventer therapy in asthma and for allergic rhinitis.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Administration (by indications): • Asthma ( 2.1 ): Once daily in the evening for patients 2 years and older. • Acute prevention of EIB ( 2.2 ): One tablet at least 2 hours before exercise for patients 6 years of age and older. • Seasonal allergic rhinitis ( 2.3 ): Once daily for patients 2 years and older. • Perennial allergic rhinitis ( 2.3 ): Once daily for patients 2 years and older. Dosage (by age) ( 2 ): • 15 years and older: one 10-mg tablet. • 6 to 14 years: one 5-mg chewable tablet. • 2 to 5 years: one 4-mg chewable tablet. Patients with both asthma and allergic rhinitis should take only one dose daily in the evening ( 2.4 ). 2.1 Asthma Montelukast sodium should be taken once daily …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2026-03-05. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It blocks cysteinyl leukotriene receptors, reducing airway inflammation, bronchoconstriction and mucus.

Prescribing in practice

  • It is a regular preventer taken in the evening, not a reliever.
  • Neuropsychiatric reactions (sleep disturbance, mood and behaviour change, rarely suicidal thoughts) are recognised — counsel patients and carers to report them (MHRA alert).
  • It is an add-on, not a replacement for inhaled corticosteroids in most asthma.

Monitoring

Review asthma control and ask specifically about mood, sleep and behaviour changes.

Counselling the patient

  • Take it regularly in the evening to prevent symptoms — it is not for sudden attacks.
  • Report any new mood, sleep or behaviour changes, including in children.
  • Continue your inhalers as prescribed.

Evidence & guidelines

An add-on option in asthma and for allergic rhinitis (NICE NG80), with an MHRA warning on neuropsychiatric effects.

Reference: MHRA Drug Safety Update (2019 and 2020) Montelukast; BSACI Rhinitis Guidelines 2017; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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