Montelukast Sandoz (Montelukast)

Montelukast acts on the leukotriene pathway to control airway inflammation and bronchoconstriction. It is indicated for the following conditions:

• Asthma: provides maintenance therapy that reduces the frequency of exacerbations and improves lung function.
• Allergic rhinitis: alleviates nasal congestion, sneezing and itching associated with seasonal or perennial allergies.
• Exercise‑induced bronchoconstriction: prevents airway narrowing that occurs during or after physical activity.

• Montelukast selectively blocks the cysteinyl leukotriene receptor CysLT1, preventing leukotriene‑D4 from binding. This inhibition reduces leukotriene‑mediated bronchoconstriction, vascular permeability, and eosinophilic inflammation in the respiratory tract, thereby improving airway patency and decreasing allergic inflammation.

Adverse reactions may occur with any medication. The following side‑effects have been reported for Montelukast.

Common Side Effects

• Headache: mild to moderate pain in the head region.
• Abdominal pain: discomfort or cramping in the stomach area.
• Nausea: feeling of queasiness that may lead to vomiting.
• Cough: persistent dry or productive cough.
• Dizziness: sensation of light‑headedness or unsteadiness.
• Fatigue: unusual tiredness or lack of energy.

Serious or Rare Side Effects

• Allergic reactions: rash, angioedema, or anaphylaxis requiring immediate medical attention.
• Neuropsychiatric events: depression, mood changes, or suicidal thoughts.
• Hepatic enzyme elevation: abnormal liver function tests.
• Stevens‑Johnson syndrome: severe skin blistering and mucosal involvement.
• Eosinophilic granulomatosis with polyangiitis: rare vasculitic disorder.
• Severe bronchospasm: sudden worsening of breathing difficulty.

Before initiating therapy, consider the following safety measures.

• Assess asthma control: ensure baseline control before adding Montelukast.
• Monitor neuropsychiatric symptoms: watch for mood changes, depression or suicidal ideation.
• Use cautiously in hepatic impairment: dose adjustment may be required for patients with liver disease.
• Avoid in known hypersensitivity: discontinue if allergic reaction occurs.
• Review concomitant medications: check for potential drug‑drug interactions.
• Store at room temperature: keep in the original pack, protect from moisture and direct sunlight.

Montelukast may interact with other medicines; some combinations require avoidance while others need monitoring.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): may markedly reduce Montelukast exposure and effectiveness.
• Co‑administration with other leukotriene modifiers (e.g., zafirlukast, zileuton): increases risk of adverse hepatic and neuropsychiatric effects.

Moderate Interactions (Monitor Closely)

• Antidepressants (SSRIs, SNRIs): may potentiate neuropsychiatric adverse events.
• Warfarin: occasional alterations in INR; monitor coagulation parameters.
• Beta‑agonists (short‑acting): additive bronchodilatory effect may require dose adjustment.