Montelukast Accord Healthcare Ireland (Montelukast)

Montelukast is a leukotriene receptor antagonist used to manage respiratory allergic conditions.

• Asthma: Improves control of chronic asthma and reduces frequency of exacerbations.
• Allergic rhinitis: Relieves nasal congestion, sneezing and itching associated with seasonal or perennial allergic rhinitis.
• Exercise‑induced bronchoconstriction: Prevents airway narrowing triggered by physical activity.

• Montelukast selectively blocks the cysteinyl leukotriene receptor type 1 (CysLT1) on airway smooth‑muscle cells, mast cells and eosinophils. By antagonising this receptor, it prevents leukotriene D4‑mediated bronchoconstriction, mucus secretion and inflammatory cell recruitment, thereby reducing airway hyper‑responsiveness, vascular permeability and edema in the respiratory mucosa.

Montelukast may cause a range of adverse reactions, most of which are mild and reversible.

Common Side Effects

• Headache: mild to moderate intensity.
• Upper respiratory tract infection: sore throat or nasal congestion.
• Abdominal pain: stomach discomfort.
• Diarrhoea: loose stools.

Serious or Rare Side Effects

• Allergic reactions: rash, itching, swelling, or anaphylaxis.
• Mood changes: depression, anxiety, or suicidal thoughts.
• Hepatotoxicity: elevated liver enzymes or hepatitis.
• Angioedema: swelling of lips, tongue or face.

When prescribing Montelukast, clinicians should consider several safety precautions to minimise risk.

• Assess asthma control: ensure patient’s asthma is adequately managed before initiating therapy.
• Monitor for mood changes: watch for signs of depression or suicidal ideation.
• Evaluate liver function: consider baseline hepatic assessment in patients with liver disease.
• Use with caution in the elderly: adjust monitoring due to potential comorbidities.
• Avoid in known hypersensitivity: discontinue if allergic reaction occurs.
• Store at ambient temperature: keep below 25 °C in the original container, protect from moisture.

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

Major Interactions (Avoid)

• Phenobarbital, carbamazepine, rifampin: strong enzyme inducers that may reduce montelukast plasma levels.
• Ritonavir or other potent CYP3A4 inhibitors: may increase montelukast exposure and risk of adverse effects.

Moderate Interactions (Monitor Closely)

• Warfarin: possible alteration of anticoagulant effect; monitor INR.
• Theophylline: additive bronchodilator effects; observe for increased side effects.
• Antidepressants (e.g., fluoxetine): potential for enhanced central nervous system effects.