Montelukast Sandoz Ltd (Montelukast)

Montelukast is indicated for conditions involving leukotriene‑mediated airway inflammation.

• Asthma: improves symptom control and reduces the frequency of exacerbations.
• Exercise‑induced bronchoconstriction: prevents airway narrowing triggered by physical activity.
• Allergic rhinitis: alleviates nasal congestion, sneezing and itching associated with seasonal allergies.

• Montelukast selectively blocks the cysteinyl leukotriene receptor CysLT1, preventing leukotrienes D4, C4 and E4 from binding. This inhibition reduces bronchoconstriction, vascular permeability, and inflammatory cell recruitment in the airways, thereby diminishing airway hyper‑responsiveness and mucus secretion associated with asthma and allergic rhinitis.

Montelukast may cause a range of adverse reactions, most of which are mild and reversible.

Common Side Effects

• Headache: mild to moderate intensity.
• Upper respiratory tract infection: nasopharyngitis or common‑cold symptoms.
• Abdominal pain: discomfort in the stomach area.
• Cough: non‑productive cough.

Serious or Rare Side Effects

• Neuropsychiatric events: agitation, depression, or suicidal thoughts.
• Allergic reactions: rash, angioedema, or anaphylaxis.
• Hepatotoxicity: elevated liver enzymes or hepatitis (rare).

When prescribing Montelukast, clinicians should consider several precautionary measures.

• Pregnancy: safety data are limited; use only if potential benefit justifies risk.
• Breastfeeding: excreted in milk; weigh benefits against possible effects on infant.
• Hepatic impairment: dose adjustment may be needed in moderate to severe liver disease.
• Concomitant asthma therapy: continue other controller medications; Montelukast is not a rescue drug.
• Monitoring: observe for neuropsychiatric symptoms, especially in children and adolescents.
• Store at ambient temperature: keep below 25°C in the original packaging, protect from moisture.

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

Major Interactions (Avoid)

• Phenobarbital, carbamazepine, rifampin: strong enzyme inducers that may reduce montelukast plasma levels.
• Ritonavir or other potent CYP3A4 inhibitors: may increase montelukast exposure, raising risk of adverse effects.

Moderate Interactions (Monitor Closely)

• Warfarin: possible alteration of anticoagulant effect; monitor INR.
• Theophylline: additive bronchodilator effect; observe for increased side effects.
• Antidepressants (e.g., fluoxetine): may increase risk of neuropsychiatric events; monitor mood changes.