Melarth (Montelukast)

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

• Asthma: reduces symptom frequency, improves lung function and decreases exacerbations.
• Allergic rhinitis: alleviates nasal congestion, sneezing, itching and rhinorrhea.
• Exercise‑induced bronchoconstriction: prevents bronchospasm triggered by physical activity.

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

Common Side Effects

• Headache: mild to moderate pain often transient.
• Abdominal pain: discomfort or cramps in the stomach area.
• Cough: occasional irritation of the throat.
• Nausea: feeling of unease or urge to vomit.
• Sore throat: irritation or pain in the throat.
• Fatigue: general feeling of tiredness.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips or tongue.
• Stevens‑Johnson syndrome: severe skin reaction with blistering.
• Eosinophilic granulomatosis with polyangiitis: rare vasculitis.
• Hepatic injury: abnormal liver function tests.
• Anaphylaxis: life‑threatening allergic reaction.
• Mood changes: including depression or suicidal thoughts.

Precautions should be considered before initiating therapy with Montelukast.

• Liver function assessment: evaluate hepatic status, especially in patients with known liver disease.
• Neuropsychiatric monitoring: watch for mood changes, depression or suicidal ideation.
• Severe hepatic impairment: use with caution and adjust therapy as needed.
• Hypersensitivity: avoid in individuals with known allergy to Montelukast or excipients.
• Drug interactions: review concomitant medications for potential interactions.
• Store at room temperature: keep in the original packaging, protect from moisture and light.

Montelukast may interact with several medicines; clinicians should assess the risk.

Major Interactions (Avoid)

• Ketoconazole: strong CYP3A4 inhibition may increase Montelukast levels.
• Ritonavir: potent CYP3A4 inhibitor can raise exposure.
• Phenobarbital: enzyme inducer that reduces efficacy.
• Carbamazepine: induces metabolism, decreasing therapeutic effect.
• Rifampin: strong inducer leading to reduced plasma concentrations.

Moderate Interactions (Monitor Closely)

• Warfarin: may alter anticoagulant effect.
• Theophylline: potential additive bronchodilator effect.
• Beta‑agonists: monitor for enhanced bronchodilation.
• NSAIDs: watch for increased gastrointestinal irritation.
• Oral contraceptives: possible reduction in contraceptive efficacy.