Montelukast Dr. Reddy's Laboratories (Uk) (Montelukast)

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

• Asthma: helps prevent bronchospasm and reduces the frequency of asthma attacks.
• Allergic rhinitis: relieves nasal congestion, sneezing and itchy eyes caused by seasonal allergies.
• Exercise‑induced bronchoconstriction: reduces airway narrowing that can occur 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 airflow and decreasing allergic inflammation.

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

Common Side Effects

• Headache: mild to moderate pain often reported during early treatment.
• Abdominal pain: discomfort or cramps in the stomach region.
• Cough: transient irritation of the throat.
• Dizziness: occasional light‑headed sensation.
• Fatigue: feeling unusually tired.
• Nausea: mild queasiness.

Serious or Rare Side Effects

• Stevens‑Johnson syndrome: severe skin reaction requiring immediate medical attention.
• Angioedema: swelling of the face, lips, or tongue.
• Hepatic injury: abnormal liver function tests.
• Anaphylaxis: rapid, life‑threatening allergic response.
• Neuropsychiatric events: mood changes, depression, or suicidal thoughts.
• Rash with eosinophilia: skin eruption accompanied by elevated eosinophil count.

Before initiating therapy, consider the following safety measures.

• Liver function monitoring: assess baseline hepatic enzymes and repeat if symptoms arise.
• Neuropsychiatric vigilance: watch for mood swings, depression, or suicidal ideation.
• Hypersensitivity assessment: discontinue if signs of allergic reaction appear.
• Pregnancy considerations: use only if potential benefit outweighs risk, as safety data are limited.
• Concomitant drug review: evaluate for possible interactions that may alter efficacy.
• Store below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Montelukast may interact with other medicines, influencing its effectiveness or safety.

Major Interactions (Avoid)

• Ketoconazole: strong CYP3A4 inhibition can increase montelukast levels.
• Itraconazole: similar CYP3A4 inhibition risk.
• Erythromycin: may raise systemic exposure.

Moderate Interactions (Monitor Closely)

• Phenobarbital: enzyme induction may reduce montelukast concentration.
• Rifampin: hepatic induction can lower drug exposure.
• Warfarin: potential alteration of anticoagulant effect, requiring INR monitoring.