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Montelukast Sodium

Why is it prescribed?

Montelukast is indicated in adult and children 2 years of age and older for the prevention and chronic treatment of asthma, including prevention of day- and night- time symptoms, the treatment of acetylsalicylic acid (ASA)- sensitive asthmatic patients, and the prevention of exercise- induced bronchoconstriction.
Montelukast is effective alone or in combination with other agents used in the maintenance treatment of chronic asthma. Montelukast and inhaled corticosteroids may be used together to control asthma or to reduce the inhaled corticosteroid dose. 
In patients who continue to experience asthma symptoms, Montelukast can be an additional treatment option following initial management with an as needed short-acting bronchodilator (SABA), an inhaled corticosteroid, or inhaled corticosteroid together with a long-acting bronchodilator.
In adults, Montelukast can be a treatment option after as needed SABAs if patients remain symptomatic and cannot or will not use an inhaler device or would prefer not to be treated with an inhaled corticosteroid.
In children, Montelukast can be a treatment option after as needed SABAs if patients remain symptomatic and cannot appropriately use an inhaler device.
Montelukast can be a treatment option in patients who experience exercise-induced bronchoconstriction.
Montelukast is indicated for the relief of symptoms of seasonal allergic rhinitis in patients 15 years old or older. Montelukast should be considered when other treatments are not effective or not tolerated

Along with its needed effects, montelukast may cause some unwanted or undesirable effects. Generally, montelukast is well tolerated and many people will not experience unwanted effects. The frequency and severity of these effects is dependant on many factors including dose, duration of therapy and individual susceptibility. Possible unwanted effects include:

  • stomach pain
  • headache
  • thirst
  • diarrhea
  • hyperactivity
  • skin rash
  • allergy

If these symptoms persist, are very troublesome, or if any unusual symptom appears consult with your pharmacist or doctor.
Very rarely, more serious adverse effects may occur. These include:

  • agitation including aggressive behavior (including temper tantrums in pediatric patients), very rarely reported as serious; anxiousness, depression, irritability, restlessness, sleep disorders including dream abnormalities and insomnia, suicidal thinking and behavior (suicidality), tremor, visual hallucinations.
  • increased bleeding tendency
  • dizziness, drowsiness, and very rarely seizure
  • nose bleeds
  • diarrhea, stomach upset, nausea, vomiting

If any of the above, rare adverse reactions occur, they should be reported to your doctor.


Montelukast is a leukotriene receptor antagonist that blocks substances in the lungs called leukotrienes. Leukotrienes cause narrowing and swelling of airways in the lungs. Blocking leukotrienes improves asthma symptoms and helps prevent asthma attacks.

It is important to understand that montelukast is not a bronchodilator and should not be used as rescue medication in acute asthmatic episodes. You should have a short-acting bronchodilator (e.g. salbutamol) available for rescue purposes.
Montelukast can be used alone or with inhaled and oral cortiosteroids (e.g. fluticasone) to prevent asthma attacks.
Do not stop taking or reduce the dosage of your other asthma medications without consulting your doctor.
Some people taking montelukast may be able to reduce or stop corticosteroid medication. If your doctor decides this is appropriate for you, reduce your corticosteroid dose gradually and report any increase in asthma symptoms to your doctor immediately.
Drug Interactions: To date, there have been no reports of drug interactions involving montelukast. However, it is still important that you inform your doctor and pharmacist of all the prescription and over-the counter medications that you are taking.
Use is not recommended in the following situations:

  • allergy to montelukast or any component of the formulation

Caution is recommended in the following situations:

  • severe liver disease
  • phenylketonuria (chewable tablets only)

Use in pregnancy: Human data is limited.  Although usually considered safe for use in pregnancy, consult your doctor or pharmacist before use.
Use while breastfeeding: It is not known whether or not montelukast is passed into breast-milk. Consult your doctor or pharmacist before using montelukast while breastfeeding.