Montelukast Krka (Montelukast)

Montelukast acts on the leukotriene pathway, a key mediator of airway inflammation and allergic responses.

• Asthma: Improves control of chronic symptoms and reduces frequency of exacerbations.
• Allergic rhinitis: Alleviates nasal congestion, sneezing and itchy eyes associated with seasonal allergies.
• Exercise‑induced bronchoconstriction: Prevents airway narrowing triggered by physical activity.

• Montelukast selectively blocks the cysteinyl leukotriene receptor CysLT1 on airway smooth‑muscle cells, mast cells and eosinophils. By antagonizing this receptor, it inhibits leukotriene‑mediated bronchoconstriction, vascular permeability, mucus secretion and inflammatory cell recruitment, thereby reducing airway inflammation and hyper‑responsiveness associated with asthma and allergic rhinitis. The drug has a high affinity for the receptor, providing sustained inhibition after once‑daily dosing, and does not affect prostaglandin pathways.

Montelukast may cause a variety of adverse reactions, which are classified by frequency.

Common Side Effects

• Headache: mild to moderate pain in the head.
• Upper respiratory tract infection: symptoms such as sore throat or runny nose.
• Abdominal pain: discomfort or cramps in the stomach area.
• Cough: occasional dry or productive cough.

Serious or Rare Side Effects

• Allergic reactions: rash, itching, swelling, or anaphylaxis.
• Neuropsychiatric events: mood changes, depression, or suicidal thoughts.
• Liver enzyme elevations: abnormal liver function tests indicating possible hepatic injury.

When prescribing Montelukast, clinicians should observe several safety and handling considerations.

• Contraindications: Not for patients with known hypersensitivity to Montelukast or any component of the formulation.
• Pregnancy and lactation: Use only if the potential benefit justifies the potential risk; discuss with a healthcare professional.
• Monitoring: Observe for new or worsening neuropsychiatric symptoms, especially in adolescents.
• Drug interactions: Review concomitant medications for potential major or moderate interactions.
• Renal or hepatic impairment: Dose adjustments may be required; assess organ function before initiating therapy.
• Store at ambient temperature: keep in the original container, protect from moisture and direct sunlight.

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

Major Interactions (Avoid)

• Phenobarbital: may reduce plasma concentrations of Montelukast, decreasing efficacy.
• Rifampin: induces hepatic enzymes that can lower Montelukast levels.
• Strong CYP3A4 inhibitors: may increase Montelukast exposure, raising risk of adverse effects.

Moderate Interactions (Monitor Closely)

• Antidepressants (e.g., fluoxetine): potential for additive neuropsychiatric effects.
• Antihistamines: may mask symptoms of allergic reactions.
• Warfarin: monitor INR as Montelukast could affect coagulation parameters.