Montelukast Sodium

Innovator's Monograph

Pharmacology

Montelukast Sodium 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 contributes to the signs and symptoms of asthma.

INDICATION

Montelukast Sodium is a leukotriene receptor antagonist indicated for:

Prophylaxis and chronic treatment of asthma in patients 12 months of age and older.
Acute prevention of exercise-induced bronchoconstriction (EIB) in patients 6 years of age and older.
Relief of symptoms of Allergic Rhinitis (AR): Seasonal Allergic Rhinitis (SAR) in patients 2 years of age and older, and perennial allergic rhinitis (PAR) in patients 6 months of age and older.

DOSAGE By indications

Asthma: Once daily in the evening for patients 12 months and older.
Acute prevention of EIB: One tablet at least 2 hours before exercise for patients 6 years of age and older.
Seasonal Allergic Rhinitis: Once daily for patients 2 years and older.
Perennial Allergic Rhinitis: Once daily for patients 6 months and older.

By age:

15 years and older: One 10mg tablet.
6 to 14 years: One 5mg tablet.
2 to 5 years: One 4 mg tablet.

ADMINISTRATION

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

Interaction

Montelukast Sodium may be administered with other therapies routinely used in the prophylaxis and chronic treatment of asthma. In drug-interaction studies, the recommended clinical dose of Montelukast Sodium did not have clinically important effects on the following medicinal products: theophylline, prednisone, prednisolone, oral contraceptives, terfenadine, digoxin, and warfarin. Caution should be exercised, particularly in children, when Montelukast Sodium is coadministered with phenytoin, phenobarbital, and rifampicin.

CONTRADICTION

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

Side Effects

Montelukast Sodium appears to be well tolerated. In clinical trials, the most common adverse effect reported was a headache, occurring in approximately 18% of patients. Rash, dyspepsia, dizziness, pharyngitis and abdominal pain were all reported in less than 2% of patients. Elevated liver transaminases have been reported with Montelukast Sodium use, but not at a greater incidence than with placebo. A small percentage of pediatric patients have experienced diarrhea, sinusitis and otitis media during Montelukast Sodium clinical trials.

PREGNANCY AND LACTATION

Montelukast Sodium is classified as pregnancy category B. The drug has been shown to cross the placenta of pregnant rats and rabbits, but there have been no reports of its use in pregnant women. Montelukast Sodium is also known to be excreted into breast milk, but only limited information is available on the significance of this finding. Caution should be used prior to initiating Montelukast Sodium therapy in nursing mothers.

Precautions & Warnings

Montelukast Sodium is not indicated for use in the reversal of bronchospasm in acute asthma attacks, including status asthmaticus. Patients should be advised to have appropriate rescue medication available.