Montelukast Opko (Montelukast)

Montelukast acts on the leukotriene pathway to control inflammatory airway diseases.

• Asthma: improves symptom control and reduces the frequency of exacerbations.
• Allergic rhinitis: alleviates nasal congestion, itching and sneezing caused by seasonal or perennial allergens.
• 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 inflammatory cell recruitment in the airways, thereby improving respiratory function and decreasing allergic inflammation.

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

Common Side Effects

• Headache: mild to moderate discomfort.
• Abdominal pain: occasional stomach upset.
• Cough: transient irritation of the throat.
• Nausea: feeling of queasiness.
• Dizziness: brief episodes of light‑headedness.
• Fatigue: unusual tiredness.

Serious or Rare Side Effects

• Allergic reactions: rash, angioedema, or anaphylaxis.
• Mood changes: depression, anxiety, or suicidal thoughts.
• Hepatic enzyme elevation: abnormal liver function tests.
• Stevens‑Johnson syndrome: severe skin reaction.
• Eosinophilic granulomatosis with polyangiitis: rare vasculitis.
• Severe bronchospasm: sudden worsening of breathing.

Before prescribing Montelukast, clinicians should consider several safety aspects.

• Assess asthma control: ensure patients are on appropriate inhaled therapy first.
• Review allergy history: identify prior hypersensitivity to leukotriene modifiers.
• Monitor mood: watch for depression or suicidal ideation, especially in adolescents.
• Evaluate liver function: consider baseline tests for patients with hepatic disease.
• Store at ambient temperature: keep below 25°C in the original packaging, protect from moisture and direct sunlight.

Montelukast may interact with other medicines, requiring attention to avoid reduced efficacy or increased toxicity.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampicin, carbamazepine): may markedly lower Montelukast plasma levels.
• Ritonavir or other potent CYP3A4 inhibitors: can increase exposure and risk of side effects.

Moderate Interactions (Monitor Closely)

• Warfarin: monitor INR as Montelukast may affect anticoagulation.
• Theophylline: observe for altered bronchodilator response.
• Beta‑agonists: assess for additive bronchodilatory effects and possible tachycardia.