Montelukast Alter (Montelukast)

Montelukast acts on the leukotriene pathway to reduce airway inflammation and bronchoconstriction.

• Asthma: helps prevent chronic symptoms and reduces the frequency of asthma attacks.
• Allergic rhinitis: alleviates nasal congestion, sneezing and itching caused by seasonal allergens.
• Exercise‑induced bronchoconstriction: reduces the likelihood of airway narrowing during or after physical activity.

• Montelukast selectively blocks the cysteinyl leukotriene receptor CysLT1, preventing leukotriene D4 and related mediators from binding. This inhibition reduces bronchial smooth‑muscle contraction, vascular permeability, and inflammatory cell recruitment, thereby mitigating airway narrowing and allergic inflammation associated with asthma and allergic rhinitis.

Montelukast is generally well tolerated, but adverse reactions can occur.

Common Side Effects

• Headache: mild to moderate pain in the head region.
• Upper respiratory infection: symptoms such as sore throat or nasal congestion.
• Abdominal pain: discomfort or cramping in the stomach area.
• Cough: occasional dry or productive cough.
• Diarrhea: loose stools occurring intermittently.
• Rash: mild skin irritation or redness.

Serious or Rare Side Effects

• Mood changes: depression, anxiety, or suicidal thoughts.
• Allergic reactions: hives, swelling of face or throat, difficulty breathing.
• Liver enzyme elevation: abnormal liver function test results.
• Stevens‑Johnson syndrome: severe skin blistering and mucosal involvement.
• Angioedema: rapid swelling of lips, tongue, or eyes.
• Anaphylaxis: life‑threatening systemic allergic response.

When prescribing Montelukast, clinicians should consider patient‑specific factors and safety measures.

• Pregnancy: safety data are limited; use only if the potential benefit justifies the risk.
• Breastfeeding: excreted in milk; assess risk versus benefit before continuation.
• Hepatic impairment: monitor liver function in patients with existing liver disease.
• Neuropsychiatric effects: observe for mood changes, especially in adolescents.
• Concomitant asthma therapy: do not replace inhaled corticosteroids without medical guidance.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, protect from moisture and direct sunlight.

Montelukast may interact with other medicines, influencing efficacy or safety.

Major Interactions (Avoid)

• Phenobarbital: may reduce montelukast plasma concentrations.
• Rifampin: strong enzyme inducer that can lower drug exposure.

Moderate Interactions (Monitor Closely)

• Antidepressants (e.g., fluoxetine): potential additive neuropsychiatric effects.
• Warfarin: occasional reports of altered INR; monitor coagulation parameters.
• CYP2C9 inhibitors (e.g., fluconazole): may modestly increase montelukast levels.
• Herbal supplements containing St. John’s wort: possible reduction in drug exposure.