Montelukast Aristo (Montelukast)

• Montelukast is a leukotriene receptor antagonist used to treat conditions involving airway inflammation and allergic symptoms.
• Asthma: helps decrease airway inflammation and bronchoconstriction, leading to fewer symptoms such as wheezing, coughing and shortness of breath, and reduces the need for rescue inhaler use.
• Allergic rhinitis: reduces nasal congestion, sneezing, itching and rhinorrhea by blocking leukotriene‑mediated inflammation in the nasal passages, and improves overall nasal airflow.
• Exercise‑induced bronchoconstriction: prevents the narrowing of airways that can occur during or after physical exertion, improving exercise tolerance, and supports consistent participation in sports or physical activities.

• Montelukast selectively blocks the cysteinyl leukotriene receptor type 1 (CysLT1) on airway smooth‑muscle cells, inflammatory cells and vascular endothelium. By antagonizing CysLT1, it prevents leukotriene‑D4 and related mediators from binding, thereby inhibiting leukotriene‑induced bronchoconstriction, mucus secretion, vascular permeability and eosinophilic inflammation in the respiratory tract. This action results in a reduction of airway hyper‑responsiveness and improves symptom control over time, and contributes to decreased frequency of asthma exacerbations.

Montelukast may be associated with a range of adverse reactions, varying from mild to serious.

Common Side Effects

• Headache: mild to moderate head pain that may be intermittent.
• Abdominal pain: discomfort or cramping in the stomach region.
• Cough: occasional dry cough without mucus production.
• Nausea: feeling of queasiness that may precede vomiting.
• Dizziness: light‑headed sensation, especially when standing quickly.
• Fatigue: unusual tiredness or lack of energy.

Serious or Rare Side Effects

• Allergic reaction: rash, itching, swelling of face or throat, potentially leading to anaphylaxis.
• Mood changes: new or worsening depression, anxiety, or thoughts of self‑harm.
• Liver enzyme elevation: increased ALT/AST indicating possible hepatic injury.
• Eosinophilic granulomatosis with polyangiitis: rare systemic vasculitis presenting with asthma worsening and eosinophilia.

Precautions should be observed when prescribing Montelukast.

• Pregnancy: consult a healthcare provider; safety not established.
• Breastfeeding: weigh potential benefits against possible risks.
• Pediatric use: dosage determined by age/weight; monitor for behavioral changes.
• Elderly: start at lowest effective dose and monitor for adverse effects.
• Drug interactions: review concomitant medications for potential interactions.
• Renal impairment: use with caution; monitor renal function.
• Store at ambient temperature: keep below 25°C, retain original packaging, protect from moisture and light.

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

Major Interactions (Avoid)

• Ritonavir: strong CYP3A4 inhibition can raise montelukast levels, increasing risk of adverse effects.
• Phenobarbital: enzyme induction may lower montelukast exposure, reducing efficacy.
• Carbamazepine: potent inducer of hepatic enzymes that can markedly decrease montelukast concentrations.

Moderate Interactions (Monitor Closely)

• Fluconazole: moderate CYP3A4 inhibition may modestly increase montelukast levels; monitor for side effects.
• Warfarin: possible alteration of anticoagulant effect; check INR regularly when co‑administered.