Montelukast Amarox (Montelukast)

Montelukast is used to manage conditions mediated by leukotriene pathways, primarily in respiratory allergic diseases.

• Asthma: improves control of chronic airway inflammation and reduces frequency of exacerbations.
• Allergic rhinitis: alleviates nasal congestion, sneezing and itching caused by allergic inflammation.
• Exercise‑induced bronchoconstriction: prevents airway narrowing triggered by physical activity.
• Seasonal allergic rhinitis: provides relief during pollen season by blocking leukotriene effects.

• Montelukast selectively antagonizes the cysteinyl leukotriene receptor CysLT1 located on airway smooth‑muscle cells, mast cells and eosinophils. By blocking binding of leukotriene D4 and related mediators, it prevents leukotriene‑induced bronchoconstriction, vascular permeability and inflammatory cell recruitment, thereby reducing airway edema and hyper‑responsiveness. The inhibition is dose‑dependent and persists for the dosing interval, allowing once‑daily oral administration. This pharmacologic profile contributes to its efficacy in both chronic and episodic respiratory allergic conditions.

Montelukast may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Headache: mild to moderate headache, often transient and resolves without treatment.
• Abdominal pain: discomfort or cramps in the stomach area, occasionally accompanied by indigestion.
• Cough: transient dry cough, usually mild and self‑limiting.
• Nausea: feeling of queasiness or urge to vomit, may be occasional.

Serious or Rare Side Effects

• Angioedema: rapid swelling of face, lips, tongue or throat that may compromise breathing.
• Stevens‑Johnson syndrome: severe skin reaction characterized by blistering, detachment and mucosal involvement.
• Hepatic injury: signs of liver dysfunction such as jaundice, elevated transaminases or hepatitis.

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

• Assess liver function: evaluate hepatic status before initiating therapy in patients with liver disease.
• Monitor for neuropsychiatric events: watch for mood changes, depression or suicidal thoughts during treatment.
• Use caution in children: adjust dosing according to age and weight as directed by prescriber.
• Review concomitant medications: consider potential drug interactions that may alter montelukast levels.
• Store at ambient temperature: keep below 25 °C in the original packaging, protect from moisture and direct sunlight.

Montelukast can interact with other medicines, affecting its concentration or therapeutic effect.

Major Interactions (Avoid)

• Ritonavir: strong CYP3A4 inhibition may raise montelukast plasma levels, increasing risk of adverse effects.
• Phenobarbital: potent enzyme induction can markedly reduce montelukast exposure, compromising efficacy.

Moderate Interactions (Monitor Closely)

• Fluconazole: moderate CYP3A4 inhibition may modestly increase montelukast levels; monitor for side effects.
• Carbamazepine: enzyme induction may lower montelukast concentrations; consider therapeutic monitoring.
• Warfarin: possible alteration of anticoagulant effect; check INR regularly when co‑administered.