Montelukast Normon (Montelukast Sodium)

• Montelukast acts on leukotriene pathways to control airway inflammation and bronchoconstriction.
• Asthma: improves long‑term control of chronic asthma by reducing bronchoconstriction, airway edema and inflammatory cell infiltration.
• Allergic rhinitis: relieves nasal congestion, sneezing, itching and rhinorrhea caused by seasonal or perennial allergens.
• Exercise‑induced bronchoconstriction: prevents the acute narrowing of airways that occurs during or after physical exertion, allowing better exercise tolerance.

• Montelukast selectively blocks the cysteinyl leukotriene receptor CysLT1 on airway smooth muscle, endothelial and inflammatory cells. By antagonizing leukotrienes C4, D4 and E4, it inhibits the cascade that leads to bronchoconstriction, mucus secretion, vascular permeability and eosinophilic inflammation, thereby stabilising airway tone and reducing inflammatory responses.

Montelukast may cause a range of adverse reactions, varying from mild to serious.

Common Side Effects

• Headache: mild to moderate intensity, often transient.
• Abdominal pain or dyspepsia: occasional discomfort after dosing.
• Nausea or vomiting: generally mild and self‑limiting.
• Cough: non‑productive and transient.
• Dizziness or fatigue: occasional, resolves with continued use.

Serious or Rare Side Effects

• Allergic reactions: rash, urticaria, angioedema or anaphylaxis.
• Neuropsychiatric events: mood changes, depression, anxiety or suicidal thoughts.
• Hepatic enzyme elevation: rare cases of increased transaminases.
• Severe skin reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis.

• Before initiating therapy, clinicians should consider several safety aspects.
• Assess asthma control: ensure baseline control before adding Montelukast.
• Monitor neuropsychiatric symptoms: watch for mood changes, depression or suicidal ideation.
• Use with caution in hepatic impairment: dose adjustment may be required.
• Avoid in known hypersensitivity: discontinue if allergic reaction occurs.
• Store at ambient temperature: keep below 25 °C, retain in original packaging and protect from moisture.

Montelukast can interact with other medicines, altering its effectiveness or safety.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir): may increase Montelukast plasma concentrations.
• Phenobarbital or rifampin: may markedly reduce Montelukast exposure, compromising efficacy.

Moderate Interactions (Monitor Closely)

• Antidepressants (e.g., fluoxetine, sertraline): may heighten risk of neuropsychiatric side effects.
• Warfarin: potential alteration of INR; monitor coagulation parameters.
• Beta‑agonists: additive bronchodilatory effect, may require dose adjustment of rescue inhalers.