Monalux (Montelukast)

Montelukast, as a leukotriene receptor antagonist, is used to treat several respiratory and allergic conditions that involve leukotriene‑mediated inflammation.

• Asthma: Improves long‑term control and reduces the frequency of asthma attacks in adults and children.
• Allergic rhinitis: Relieves nasal congestion, sneezing, itching and rhinorrhea associated with seasonal or perennial allergies.
• Exercise‑induced bronchoconstriction: Prevents bronchospasm triggered by physical activity, allowing better exercise tolerance.

• Montelukast selectively antagonizes the cysteinyl leukotriene receptor CysLT1, preventing leukotriene D4 and related mediators from binding. This inhibition reduces bronchial smooth‑muscle contraction, vascular permeability, mucus secretion, and eosinophilic inflammation in the airways, thereby improving respiratory function and alleviating allergic symptoms.

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: discomfort or cramps, usually resolves without intervention.
• Cough: non‑productive, may be related to underlying disease.
• Dyspepsia: indigestion or feeling of fullness.
• Fatigue: general tiredness without a clear cause.
• Dizziness: sensation of light‑headedness, often brief.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips, tongue or throat requiring immediate medical attention.
• Stevens‑Johnson syndrome: severe skin reaction with blistering and mucosal involvement.
• Eosinophilic granulomatosis with polyangiitis: rare vasculitic disorder affecting multiple organs.
• Hepatic injury: elevated liver enzymes or hepatitis.
• Neuropsychiatric events: agitation, depression, suicidal thoughts.
• Anaphylaxis: acute, life‑threatening allergic reaction.

When prescribing Montelukast, clinicians should consider several safety aspects.

• Neuropsychiatric monitoring: Observe patients for mood changes, depression or suicidal thoughts.
• Hepatic function: Assess liver status in patients with existing hepatic disease.
• Renal impairment: Use caution and consider dose adjustment in severe renal dysfunction.
• Enzyme inducers: Be aware that phenobarbital, rifampin or St. John’s wort may reduce drug exposure.
• Hypersensitivity: Avoid in individuals with known allergy to montelukast or excipients.
• Store at room temperature: Keep below 25 °C in the original packaging, protect from moisture and direct sunlight.

Montelukast can interact with other medicines, requiring attention to the level of risk.

Major Interactions (Avoid)

• Phenobarbital: potent enzyme inducer that markedly lowers montelukast plasma levels.
• Rifampin: strong inducer of hepatic metabolism, reducing therapeutic effect.
• St. John’s wort: herbal inducer that may diminish drug exposure.

Moderate Interactions (Monitor Closely)

• Warfarin: possible alteration of INR, requiring closer coagulation monitoring.
• Beta‑agonists: additive bronchodilatory effect may increase risk of tachycardia.
• ACE inhibitors: rare reports of bronchospasm; monitor respiratory status.