Montelukast is a selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene receptor (CysLT₁). The cysteinyl leukotrienes (LTC₄, LTD₄, LTE₄) are products of arachidonic acid metabolism and are released from various cells, including mast cells and eosinophils. Cysteinyl leukotrienes and leukotriene receptor occupation have been correlated with the pathophysiology of asthma & allergic rhinitis, including airway edema, smooth muscle contraction, and altered cellular activity associated with the inflammatory process, which contribute to the signs and symptoms of asthma.

Montelukast Sodium is indicated for:

• Prophylaxis and chronic treatment of asthma
• Acute prevention of Exercise-Induced Bronchoconstriction (EIB)
• Relief of symptoms of Allergic Rhinitis (AR): Seasonal & Perennial Allergic Rhinitis

Adults & adolescents (15 years & older)-

• Asthma & Allergic Rhinitis: 10 mg/day 
• Exercise-Induced Bronchoconstriction: 10 mg/day

Pediatric patients (6 to 14 years)-

• Asthma & Allergic Rhinitis: 5 mg/day 
• Exercise-Induced Bronchoconstriction: 5 mg/day

Pediatric patients (6 months to 5 years)-

• Asthma & Allergic Rhinitis: 4 mg/day 
• Exercise-Induced Bronchoconstriction: Not recommended

Patients with both asthma and allergic rhinitis should take only one dose daily in the evening. For prevention of Acute prevention of Exercise-Induced Bronchoconstriction, a single dose should be taken at least 2 hours before exercise.

Administration

Route of administration: Oral. Montelukast may be taken with or without food or as directed by the physician.

Montelukast is contraindicated in patients who are hypersensitive to any component of this product.

Common: Diarrhoea, fever, gastrointestinal discomfort, headache, nausea, vomiting, skin reactions, upper respiratory tract infection.

Uncommon: Akathisia, anxiety, arthralgia, asthenia, abnormal behavior, depression, dizziness, drowsiness, dry mouth, haemorrhage, irritability, malaise, muscle complaints, oedema, seizure, abnormal sensation, sleep disorders.

Rare: Angioedema, concentration impaired, disorientation, eosinophilic granulomatosis with polyangiitis, erythema nodosum, hallucination, hepatic disorders, memory loss, palpitations, pulmonary eosinophilia, suicidal tendencies, tremor.

Overdose Effects

There were no adverse experiences in the majority of overdosage reports. The most frequently occurring adverse experiences were consistent with the safety profile of Montelukast and included abdominal pain, somnolence, thirst, headache, vomiting and psychomotor hyperactivity. In the event of overdose, it is reasonable to employ the usual supportive measures; e.g., remove unabsorbed material from the gastrointestinal tract, employ clinical monitoring, and institute supportive therapy, if required.

Montelukast is not indicated for use in the reversal of bronchospasm in acute asthma attacks, including status asthmatic. Neuropsychiatric events including agitation, hostility, anxiousness, depression, disorientation, disturbance in attention, dream abnormalities, hallucinations, insomnia, irritability, memory impairment, restlessness, somnambulism, suicidal thinking and behavior (including suicide) and tremor.

Pregnancy & Lactation

There are no adequate and well-controlled studies in pregnant women. Montelukast should be used during pregnancy only if clearly needed. Montelukast is excreted in breast milk. So caution should be exercised when Montelukast is given to a nursing mother.