Montelukast Eg (Montelukast)

• Montelukast acts on the leukotriene pathway to control airway inflammation and allergic symptoms.
• Asthma: reduces frequency of bronchospasm and improves overall control.
• Allergic rhinitis: alleviates nasal congestion, sneezing and itching.
• Exercise‑induced bronchoconstriction: prevents airway narrowing triggered by physical activity.

• Montelukast selectively blocks cysteinyl leukotriene (CysLT1) receptors in the respiratory tract and other tissues. By antagonizing these receptors, it prevents leukotrienes D4, E4 and related mediators from binding, which reduces bronchoconstriction, mucus secretion, vascular permeability and inflammatory cell recruitment. This inhibition moderates the late‑phase allergic response and helps maintain airway patency.

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

Common Side Effects

• Headache: mild to moderate pain often transient.
• Abdominal pain: discomfort or cramps in the stomach area.
• Cough: occasional dry or productive cough.
• Nausea: feeling of queasiness or upset stomach.
• Dizziness: light‑headed sensation.

Serious or Rare Side Effects

• Allergic reactions: rash, angioedema or anaphylaxis.
• Neuropsychiatric events: mood changes, depression, suicidal thoughts.
• Hepatic enzyme elevation: increased liver transaminases.
• Severe skin reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis.

When prescribing Montelukast, clinicians should observe the following precautions.

• Assess asthma control: ensure baseline control before adding therapy.
• Monitor neuropsychiatric symptoms: watch for mood changes or suicidal ideation.
• Use caution in hepatic impairment: adjust use if liver disease is present.
• Avoid in known hypersensitivity: discontinue if allergic reaction occurs.
• Review concomitant CYP3A4 modulators: dose may need adjustment with strong inhibitors or inducers.
• Store at room temperature: keep in the original pack, protect from moisture and heat.

Montelukast can interact with other medicines, requiring attention to the interaction level.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir): may increase montelukast plasma concentrations.
• Concurrent use with other leukotriene receptor antagonists (e.g., zafirlukast): may raise risk of adverse effects.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce montelukast effectiveness.
• Fluoxetine or other SSRIs: may potentiate neuropsychiatric side effects.
• NSAIDs: may increase risk of bronchospasm in sensitive individuals.
• Warfarin: occasional reports of altered INR, monitor coagulation.