Montelukast Krka (Montelukast)

• Montelukast acts on the leukotriene pathway to manage several allergic and respiratory conditions.
• Asthma (maintenance therapy): Reduces frequency of bronchospasm, improves lung function, and decreases need for rescue inhalers in patients with persistent asthma.
• Allergic rhinitis: Alleviates nasal congestion, sneezing, itching, and rhinorrhea associated with seasonal or perennial allergic rhinitis.
• Exercise‑induced bronchoconstriction: Prevents airway narrowing triggered by physical activity, allowing better tolerance of exercise in susceptible individuals.

• Montelukast selectively blocks the cysteinyl leukotriene receptor CysLT1, preventing leukotriene D4 from binding to airway smooth‑muscle cells, submucosal glands, and inflammatory cells. This inhibition reduces bronchoconstriction, mucus secretion, vascular permeability, and eosinophilic inflammation, thereby improving airway patency and decreasing allergic inflammatory responses. The drug’s oral bioavailability allows systemic distribution, achieving therapeutic concentrations in the respiratory tract while maintaining a favorable safety profile.

Montelukast is generally well tolerated, but several adverse reactions have been reported.

Common Side Effects

• Headache
• Abdominal pain
• Cough
• Nausea
• Dizziness
• Fatigue

Serious or Rare Side Effects

• Allergic reactions such as rash, urticaria, or angioedema
• Stevens‑Johnson syndrome or toxic epidermal necrolysis
• Hepatic injury
• Neuropsychiatric events, including suicidal thoughts
• Eosinophilic granulomatosis with polyangiitis
• Anaphylaxis

When prescribing Montelukast, clinicians should consider several precautionary measures to ensure safe use.

• Pregnancy: Consult a healthcare provider; safety data are limited.
• Breastfeeding: Use with caution; limited information on excretion in milk.
• Renal impairment: Dose adjustment may be required in severe cases.
• Concomitant use with enzyme‑inducing agents: May reduce therapeutic effect.
• Known hypersensitivity: Avoid in patients with documented allergy to montelukast or any excipients.
• Store at room temperature: Keep in the original packaging, protect from moisture and heat.

Montelukast may interact with other medicines, altering its effectiveness or increasing adverse effects.

Major Interactions (Avoid)

• Phenobarbital: Induces metabolism, decreasing montelukast plasma levels.
• Rifampin: Reduces drug exposure through hepatic enzyme induction.
• Ketoconazole: May increase montelukast concentrations, raising risk of side effects.

Moderate Interactions (Monitor Closely)

• Warfarin: Potentially enhances anticoagulant effect; monitor INR.
• Beta‑agonists: May have additive bronchodilator effect; observe clinical response.
• ACE inhibitors: Monitor for increased cough or angioedema risk.