Montelukast Arena (Montelukast Sodium)

Montelukast is a leukotriene‑modifying agent used in respiratory and allergic conditions.

• Asthma: improves control of persistent asthma and reduces the frequency of exacerbations.
• Allergic rhinitis: relieves nasal congestion, sneezing and itching associated with seasonal or perennial allergic rhinitis.
• Exercise‑induced bronchoconstriction: prevents airway narrowing that occurs during or after physical activity.

• Montelukast selectively blocks the cysteinyl leukotriene receptor CysLT1, preventing leukotriene D4 and related mediators from binding. This inhibition reduces bronchial smooth‑muscle contraction, vascular permeability, mucus secretion, and inflammatory cell recruitment, thereby mitigating airway inflammation and hyper‑responsiveness.

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

Common Side Effects

• Headache: mild to moderate pain in the head region.
• Upper respiratory tract infection: symptoms such as sore throat or nasal congestion.
• Abdominal pain: discomfort or cramping in the stomach area.
• Cough: persistent or intermittent coughing.
• Diarrhoea: loose, watery stools.
• Rash: mild skin irritation or redness.

Serious or Rare Side Effects

• Allergic reactions: hives, swelling of face or throat, difficulty breathing.
• Mood changes: agitation, depression, or suicidal thoughts.
• Hepatic dysfunction: elevated liver enzymes or jaundice.
• Angioedema: rapid swelling of lips, tongue, or eyes.
• Stevens‑Johnson syndrome: severe skin blistering and detachment.
• Anaphylaxis: life‑threatening systemic allergic response.

Before prescribing Montelukast, consider the following safety measures.

• Pregnancy: consult a healthcare professional; safety data are limited.
• Lactation: assess risk versus benefit for nursing mothers.
• Hepatic impairment: monitor liver function in patients with liver disease.
• Concomitant asthma therapy: ensure patients continue their rescue inhalers as needed.
• Age restrictions: use according to approved pediatric dosing guidelines.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, protect from moisture and direct sunlight.

Montelukast may interact with other medicines; monitor patients accordingly.

Major Interactions (Avoid)

• Phenobarbital: may reduce montelukast plasma concentrations.
• Rifampin: can decrease therapeutic effect by inducing metabolism.

Moderate Interactions (Monitor Closely)

• Antidepressants (e.g., fluoxetine): potential for mood‑related side effects.
• Antihistamines: may increase sedation when combined with sedating agents.
• CYP2C9 inhibitors (e.g., fluconazole): could modestly raise montelukast levels.
• Warfarin: monitor INR as theoretical interaction exists.
• Herbal supplements (e.g., St. John’s wort): may alter drug metabolism.