Melarth (Montelukast Sodium)

Montelukast Sodium is used to manage conditions mediated by leukotrienes, primarily within the respiratory and allergic disease spectrum.

• Asthma: Improves control of chronic asthma by reducing bronchoconstriction and airway inflammation.
• Exercise‑induced bronchoconstriction: Prevents airway narrowing triggered by physical activity.
• Allergic rhinitis: Alleviates nasal congestion, sneezing and itching caused by allergic inflammation.

• Montelukast Sodium selectively blocks the cysteinyl leukotriene receptor CysLT1 on airway smooth‑muscle cells and inflammatory cells. By antagonizing this receptor, it inhibits the actions of leukotriene D4 and related mediators that cause bronchoconstriction, mucus secretion, vascular permeability, and eosinophil recruitment, thereby reducing airway inflammation and hyperresponsiveness.

Montelukast Sodium may be associated with a range of adverse reactions, most of which are mild and reversible.

Common Side Effects

• Headache: mild to moderate pain in the head.
• Upper respiratory tract infection: sore throat, nasal congestion, or cough.
• Abdominal pain: transient stomach discomfort.

Serious or Rare Side Effects

• Allergic reactions: rash, itching, swelling, or anaphylaxis.
• Neuropsychiatric events: agitation, anxiety, mood changes, or suicidal thoughts.
• Hepatotoxicity: elevated liver enzymes, hepatitis, or jaundice.

When prescribing Montelukast Sodium, clinicians should consider several precautionary measures to ensure safe use.

• Assess asthma control: confirm that the patient requires a leukotriene antagonist as part of their maintenance regimen.
• Monitor for neuropsychiatric symptoms: watch for mood changes, depression, or suicidal thoughts.
• Evaluate liver function: consider baseline liver enzymes in patients with hepatic impairment.
• Use caution in patients with a history of hypersensitivity to montelukast or any tablet excipients.
• Review concomitant medications: avoid use with strong CYP3A4 inhibitors without medical supervision.
• Store at ambient temperature: keep below 25°C in the original container, protect from moisture and direct sunlight.

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

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir): may increase montelukast plasma levels, risking toxicity.
• Phenobarbital or rifampin: may reduce montelukast effectiveness by inducing metabolism.

Moderate Interactions (Monitor Closely)

• Warfarin: potential alteration of anticoagulant effect; monitor INR.
• Theophylline: possible additive bronchospasm risk; observe respiratory status.
• Beta‑agonists: no direct interaction but combined therapy may affect overall asthma control.