Monlast (Montelukast)

Montelukast is a leukotriene receptor antagonist used to manage conditions mediated by cysteinyl leukotrienes.

• Asthma: improves lung function and decreases frequency of wheezing episodes.
• Allergic rhinitis: relieves nasal congestion, sneezing and itching.
• Exercise‑induced bronchoconstriction: prevents airway narrowing during physical activity.

• Montelukast selectively blocks the cysteinyl leukotriene receptor CysLT1, preventing leukotriene D4 and related mediators from binding. This inhibition reduces bronchoconstriction, vascular permeability, mucus secretion, and inflammatory cell recruitment in the airways, thereby mitigating the pathophysiological processes underlying asthma, allergic rhinitis and exercise‑induced bronchospasm.

Montelukast may be associated with a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Headache
• Abdominal pain
• Cough
• Nausea
• Diarrhea
• Fatigue

Serious or Rare Side Effects

• Angioedema
• Stevens‑Johnson syndrome
• Eosinophilic granulomatosis with polyangiitis
• Hepatic injury
• Anaphylaxis
• Mood changes, including depression or suicidal thoughts

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

• Assess asthma control: confirm that baseline therapy is optimized before adding Montelukast.
• Monitor neuropsychiatric events: watch for mood changes, depression or suicidal ideation.
• Use with caution in hepatic impairment: adjust therapy if significant liver disease is present.
• Avoid in patients with known hypersensitivity: discontinue if allergic reaction occurs.
• Review concomitant medications: consider potential interactions that may alter efficacy.
• Store at ambient temperature: keep in the original packaging, protect from moisture and heat.

Montelukast can interact with other medicines, requiring attention to the level of clinical significance.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): may markedly reduce Montelukast exposure.
• Phenobarbital: can lower plasma concentrations, potentially diminishing therapeutic effect.

Moderate Interactions (Monitor Closely)

• Antidepressants (SSRIs, SNRIs): may increase risk of neuropsychiatric side effects.
• Antihistamines: additive sedation may occur when combined.
• Warfarin: variable effects on anticoagulation parameters have been reported.
• Theophylline: possible additive bronchial effects, requiring monitoring of respiratory status.