Montelukast Sandoz (Montelukast)

• Montelukast is a leukotriene receptor antagonist that targets the cysteinyl leukotriene pathway, used to treat conditions driven by leukotriene‑mediated inflammation, and improve quality of life.
• Asthma: improves overall symptom control, reduces night‑time awakenings, and lowers the rate of asthma exacerbations requiring oral corticosteroids.
• Allergic rhinitis: alleviates nasal congestion, rhinorrhea, sneezing and itchy eyes, contributing to better daily functioning during pollen seasons.
• Exercise‑induced bronchoconstriction: prevents airway narrowing that occurs during or after physical activity, allowing patients to maintain exercise tolerance without acute wheezing.

• Montelukast selectively blocks the cysteinyl leukotriene receptor type 1 (CysLT1) on airway smooth‑muscle cells, mast cells and eosinophils. By antagonizing this receptor, it prevents leukotriene D4‑mediated bronchoconstriction, vascular permeability, mucus secretion and inflammatory cell recruitment, thereby reducing airway hyper‑responsiveness and nasal mucosal edema. The inhibition of leukotriene signaling also attenuates cytokine release and limits the late‑phase allergic response, contributing to sustained control of respiratory symptoms.

Montelukast is generally well tolerated, but some patients may experience adverse reactions.

Common Side Effects

• Headache: mild to moderate headache reported.
• Upper respiratory tract infection: symptoms of cold or sinusitis.
• Abdominal pain: discomfort or cramping in the stomach area.
• Cough: occasional dry cough.
• Diarrhea: loose stools.
• Rash: mild skin irritation or erythema.

Serious or Rare Side Effects

• Allergic reactions: hives, swelling, or anaphylaxis.
• Neuropsychiatric events: agitation, depression, or suicidal thoughts.
• Hepatotoxicity: elevated liver enzymes or hepatitis.
• Angioedema: swelling of lips, tongue or throat.
• Stevens‑Johnson syndrome: severe skin blistering.

• Before prescribing Montelukast, clinicians should consider several precautionary measures.
• Assess asthma control: ensure patient is on appropriate inhaled therapy before adding Montelukast.
• Monitor for neuropsychiatric symptoms: watch for mood changes, depression or suicidal ideation.
• Evaluate liver function: consider baseline hepatic tests in patients with liver disease.
• Use in pregnancy only if clearly needed: limited data on safety during gestation.
• Avoid in patients with known hypersensitivity to montelukast or excipients.
• Store at ambient temperature: keep below 25 °C, retain in original packaging and protect from moisture.

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

Major Interactions (Avoid)

• Phenobarbital: induces metabolism, reducing montelukast plasma levels.
• Rifampin: strong enzyme inducer that may lower drug exposure.

Moderate Interactions (Monitor Closely)

• Antidepressants (SSRIs, SNRIs): potential additive neuropsychiatric effects.
• Warfarin: possible alteration of anticoagulant effect, monitor INR.
• CYP2C9 inhibitors (e.g., fluconazole): may increase montelukast concentrations.
• Oral contraceptives: may slightly increase exposure, generally not clinically significant.