Makindo Medical Notes

Always check the BNF link here before prescribing.

• 💊 Montelukast is a leukotriene receptor antagonist (LTRA).
• Used as add-on therapy in chronic asthma, particularly if symptoms are uncontrolled on inhaled corticosteroids (ICS).
• Also licensed for seasonal allergic rhinitis.

⚙️ Mode of Action

• Blocks CysLT₁ receptors in the airway.
• ⬇️ Leukotriene-mediated effects → reduced bronchoconstriction, mucus secretion, oedema, and inflammation.
• Helps prevent exercise-induced and allergen-induced bronchospasm.

📋 Dose / Indications

• 🌬️ Chronic asthma prevention: 10 mg nocte (adult).
• 👦 Children 6–14 years: 5 mg chewable tablet OD.
• 👶 Children 6 months–5 years: 4 mg granules OD (BNF guidance).
• 🌼 Seasonal allergic rhinitis (when antihistamines are insufficient).

🔄 Interactions

• See BNF for details.
• Metabolised by CYP3A4/2C9 – potential interactions with enzyme inducers (e.g. rifampicin, phenytoin).

⚠️ Cautions

• ❌ Not for acute asthma attacks (no bronchodilator effect).
• 🧪 Churg–Strauss syndrome (rare): eosinophilia, neuropathy, vasculitis, rash – typically occurs when tapering steroids.
• Use with caution in patients with psychiatric history (risk of neuropsychiatric side effects).

⛔ Contraindications

• See BNF – mainly hypersensitivity to montelukast or excipients.

⚠️ Side Effects

• 🤢 GI upset, nausea, diarrhoea.
• 🤕 Headache, myalgia.
• 🌸 Rash, allergic reactions.
• 🧠 Neuropsychiatric effects (agitation, sleep disturbance, depression, suicidal thoughts – rare but serious).
• 🧪 Churg–Strauss syndrome (rare, associated with systemic eosinophilia).
• Dry mouth, thirst (less common).

📊 Monitoring

• Routine FEV₁ and symptom control (asthma monitoring).
• Clinical vigilance for neuropsychiatric changes.
• If systemic features → consider vasculitis screen, CXR, FBC (to assess eosinophilia).

📚 References

• BNF: Montelukast
• NICE Asthma Guideline (NG80)