Montelukast Eg (Montelukast)

Montelukast acts on the leukotriene pathway to control chronic respiratory conditions.

• Asthma: provides maintenance therapy that reduces the frequency of exacerbations and improves lung function.
• Allergic rhinitis: relieves nasal congestion, sneezing and itching associated with seasonal or perennial allergies.
• Exercise‑induced bronchoconstriction: prevents bronchospasm triggered by physical activity, allowing better exercise tolerance.

• Montelukast selectively blocks the cysteinyl leukotriene receptor CysLT1, preventing leukotriene D4 from binding. This inhibition reduces leukotriene‑mediated bronchoconstriction, vascular permeability, and inflammatory cell recruitment in the airways, thereby improving respiratory function and decreasing allergic inflammation.

Montelukast is generally well tolerated, but adverse reactions can occur.

Common Side Effects

• Headache: mild to moderate pain often resolves without intervention.
• Abdominal pain: discomfort in the stomach area, usually transient.
• Cough: occasional irritation of the throat.
• Nausea: feeling of queasiness, may improve with food.
• Dizziness: light‑headed sensation, typically short‑lived.
• Fatigue: mild tiredness.

Serious or Rare Side Effects

• Allergic reactions: rash, angioedema, or anaphylaxis requiring immediate medical attention.
• Mood changes: depression, anxiety, or suicidal thoughts, especially in children.
• Liver enzyme elevation: abnormal liver function tests, monitor if symptomatic.
• Stevens‑Johnson syndrome: severe skin reaction, rare but requires urgent care.

Before initiating therapy, consider the following safety measures.

• Assess liver function: monitor patients with existing hepatic disease.
• Review psychiatric history: observe for mood alterations or depressive symptoms.
• Use caution in pregnancy: discuss potential risks with the prescriber.
• Avoid in known hypersensitivity: discontinue if allergic reaction occurs.
• Adjust in severe renal impairment: consider dose evaluation.
• Store below 25°C: keep in the original pack, protect from moisture.

Montelukast may interact with other medicines, affecting its efficacy or safety.

Major Interactions (Avoid)

• Rifampin: induces metabolism, reducing montelukast levels.
• Phenobarbital: increases hepatic clearance, lowering effectiveness.
• Carbamazepine: accelerates metabolism, potentially decreasing therapeutic effect.

Moderate Interactions (Monitor Closely)

• Ketoconazole: may increase montelukast concentrations.
• Oral contraceptives: montelukast may reduce contraceptive efficacy, requiring additional protection.