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Montelukast - Uses, Dosage, Side Effects, Drug Warnings, and Precautions

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Montelukast - Uses, Dosage, Side Effects, Drug Warnings, and Precautions

6 min read


Montelukast is a leukotriene inhibitor, which is used for treating asthma attacks in adults and children. Learn about its uses, dosage, drug warnings, side effects, precautions, drug interactions, and more.

Medically reviewed by

Dr. Penchilaprasad Kandikattu

Published At February 23, 2022
Reviewed AtMarch 17, 2023


Montelukast was introduced in 1990, and it was approved for clinical use by the FDA (Food and Drug Administration) with the brand name Singulair. This drug belongs to the class leukotriene receptor antagonist (LTRA). Leukotrienes are chemical substances that the body releases when inhaling allergens. As it was realized that cysteinyl leukotrienes are essential mediators of bronchial asthma, efforts were made to develop their antagonists and synthesis inhibitors. Now, three leukotriene receptor antagonists, Montelukast, Pranlukast, and Zafirlukast, are available.

Montelukast is used in addition to inhaled corticosteroids, demonstrating its effectiveness in asthma therapy. In addition, it may cause serious life-threatening mental changes when it is misused or stopped abruptly.


This tablet contains

  1. Active Ingredient: Montelukast sodium.
  2. Inactive Ingredients:
  • Microcrystalline cellulose.
  • Lactose monohydrate.
  • Croscarmellose sodium.
  • Hyprolose.
  • Magnesium stearate.

Drug Group:

Montelukast belongs to the class of drugs called leukotriene receptor antagonists (LRAs). This drug stops the narrowing of airways caused by inflammation, thus promoting easier breathing. Also, it helps to prevent episodes of asthma and other allergies.

What Is Montelukast Used For?

The uses of Montelukast are as follows,

  1. Prophylactic in Bronchial Asthma: It helps prevent asthma symptoms such as wheezing and shortness of breath.
  • Mild to Moderate Asthma - It is used as an alternative to inhaled Glucocorticoids. Though efficacy is low, they may decrease the need for inhaled steroids and be more acceptable in children.
  • Severe Asthma - In severe asthma, they have an additive effect with inhaled Glucocorticoids, which may help reduce steroid dose.
  1. It is useful in Aspirin-induced asthma.
  2. It is useful in exercise-induced asthma (bronchospasm) and is usually taken before starting exercises to prevent breathing problems.
  3. It helps to decrease the number of asthma attacks.
  4. It decreases the usage of the rescue inhaler.
  5. It is helpful to relieve hay fever symptoms.
  6. Allergic rhinitis - It is used in perennial and seasonal allergic rhinitis to relieve,
  • Sneezing.
  • Stuffy nose.
  • Itchy nose.

Note: It is not useful in COPD (chronic obstructive pulmonary disease).

How Does Montelukast Work?

  • Montelukast works by blocking the actions of leukotrienes (chemical substances), which may cause or worsen allergic reactions and asthma. Asthma patients tend to develop,
  1. Bronchodilation.
  2. Reduced sputum eosinophil count.
  3. Suppression of bronchial inflammation.
  4. Discharge of mucus.
  5. Hyperreactivity.
  • The cysteinyl leukotrienes receptors (cysLT1) act on bronchial smooth muscles and follow the metabolism of arachidonic acid via the 5-lipoxygenase pathway and yield the cysteinyl leukotrienes, which activate cysteinyl leukotriene receptors to cause,
  1. Bronchoconstriction.
  2. Stimulate mucus secretion.
  3. Increase capillary permeability, which leads to pulmonary edema.
  4. Increase in population of eosinophils.
  • So, Montelukast competitively blocks cysteinyl leukotrienes receptors (cysLT1) and thus blocks the effects of cysteinyl leukotrienes.


In asthmatics, Montelukast helps to -

  • Suppress bronchial inflammation.
  • Decreases mucus secretion.
  • Decreases edema.
  • Produce bronchodilation.
  • Decreases bronchial hyper-reactivity.

Onset Of Action:

Montelukast has 64% of oral bioavailability and is well absorbed orally. It is highly bound to plasma protein and is metabolized by CYP2C9 and CYP3A4 as well. It reaches its peak plasma concentration at 3 to 4 hours of taking the drug, which helps to reduce leukotriene levels in the body.

Expiry Date:

Avoid taking this medicine after it expires. The Montelukast tablet does not work and may lead to serious side effects when it is taken beyond the expiry date. So before taking medicine, verify the expiry date printed on the back of the pack or ask your pharmacist or doctor in case of any doubts.

What Is the Dosage and Administration of Montelukast?

Dosage and administration of Montelukast depend on the following,

  • Age of the patient.
  • Signs and symptoms they suffer from.
  • Medical history of the patient.
  • Patient's response to treatment.

Preparations and Doses:

The available forms of Montelukast for both adults and children are,

Montelukast for both adults and children

Usual Dosage of Montelukast:

Usual Dosage of Montelukast

Montelukast Dosage for Elderly patients:

  • For elderly patients, the kidneys will not function normally, and so this drug will be processed very slowly.
  • This can lead to serious side effects as the drug stays in the body for a longer period due to improper renal function.
  • This drug, when given to elderly patients, the doctor will lower the dose or change the dosing schedule in order to prevent the building up of the drug too much in the body.

Patients with Both Asthma and Allergic Rhinitis:

For patients above 12 years of age, suffering from asthma and allergic rhinitis, one dose to be taken at bedtime.

How to Use Montelukast?

  • The Patient Should Do the Following:
  1. Before using this medicine, ask your doctor if you have any questions or doubts.
  2. As directed by the doctor, this medicine is taken by mouth with or without food.
  3. Chewable tablets - Before swallowing, chew them thoroughly and if your child cannot chew, consult the doctor for more advice.
  4. Every day, take medicine at the same time.
    • For asthma or both asthma and allergies - Take the tablet in the evening.
    • For allergies - Take the tablet in the morning or evening.
    • For breathing problems during exercise - Take the tablet at least two hours before activity.
  • The Patient Should Not Do the Following:
  1. Taking more than one dose in 24 hours.
  2. Taking a dose before exercise if already taking this medication for asthma or allergies.
  3. Suddenly stopping the medicine or increasing or decreasing the dose by yourself.

Missed Dose:

Usually, Montelukast is taken as instructed by the doctor, and in case if your doctor has instructed you to take it regularly, the missed dose can be taken as soon as you remember it. But if it is time for the next dose, you do not want to take the missed dose, and you can continue with your regular dosing schedule. Also, do not take a double dose in order to compensate for a missed one.

What Are the Drug Warnings and Precautions?

  1. Montelukast should not be given for acute asthma attacks, including status asthmaticus.
  2. Chewable tablets of Montelukast may contain Phenylalanine, so talk to your doctor before using it if you have phenylketonuria.
  3. Do have appropriate rescue medication.
  4. Do not take Montelukast with aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) when you are aspirin-sensitive.
  5. Do not take Montelukast when bronchoconstriction has resulted from Aspirin or NSAIDs.
  6. Do not abruptly substitute Montelukast for corticosteroids, and it should be gradually reduced.
  7. Do not take the medication on your own or change the dosage because it is reported to have neuropsychiatric events.
  8. Pregnancy - Montelukast has no acceptable risks when used during the period of pregnancy.
  9. Lactation - Using Montelukast during lactation should be discussed with the doctor because it is unknown whether it is excreted in breast milk.
  10. Keep it out of children’s reach because it can lead to behavioral changes and serious life-threatening side effects when it is misused.

What Are the Side Effects of Montelukast?

  • Common Side Effects:

The following are the most common side effects, and they usually go within a few days to weeks. But if it becomes severe and persists for more than a couple of weeks, seek a doctor.

  • Fever.
  • Bedwetting in children.
  • Diarrhea.
  • Indigestion.
  • Runny nose.
  • Drowsiness.
  • Abdominal pain.
  • Infection in the nose.
  • Ear infection.
  • Gastroenteritis.
  • Sinus infection.
  • Cough.
  • Rashes.
  • Viral infection.
  • Headache.
  • Infection in the throat.
  • Sore throat.
  • Stomach pain.
  • Flu.
  • Laryngitis.
  • Bronchitis.
  • Serious Side Effects:

Serious side effects should be given care and treated immediately. If you feel any of the symptoms for a prolonged period, get emergency medical care as these symptoms are life-threatening. Serious side effects are,

  • Inflammation of blood vessels -
  1. Numbness of the arms and legs.
  2. Fever.
  3. Cold sweats.
  4. Swelling of the sinuses.
  5. Muscle aches.
  • Muscle spasms.
  • Anaphylaxis.
  • Palpitations.
  • Nosebleeding.
  • Pancreatitis.
  • Joint pain.
  • Stevens-Johnson syndrome (medical emergency) -
  1. Red rashes.
  2. Swelling of the face.
  3. Skin pain.
  4. Hives.
  5. Swelling of the tongue.
  • Systemic eosinophilia -
  1. Fever.
  2. Muscle aches.
  3. Numbness of the arms and legs.
  4. Cold sweats.
  • Increased bleeding in,
  1. Skin - From cuts.
  2. Urine.
  3. Feces.
  • Rare Side effects:
  • Churg-Strauss syndrome.
  • Behavior changes -
  1. Tremors.
  2. Bad dreams.
  3. Anxiety.
  4. Confusion.
  5. Hallucination.
  6. Sleepwalking.
  7. Restlessness.
  8. Agitation.
  9. Sleeping trouble.
  10. Suicidal thoughts.
  • Neuropathy.
  • Cholestatic hepatitis.

What Are the Drug Interactions of Montelukast?

  1. Certain drugs can change their effect when it interacts with other drugs or herbal products, increasing the risk of serious side effects and causing the medications not to work properly. So, it is essential to tell your doctor all the prescription, nonprescription, and herbal medicines you are taking.
  2. If you have already faced drug interactions with this drug and even though you have instructed the doctor, you have been prescribed with Montelukast, do not stop or change the dosage because the doctor will take you on a follow-up or have close monitoring of the drug.
  3. Montelukast does not cause severe interactions but is known to have serious interactions with,
    • Idelalisib.
    • Ivacaftor.
    • Warfarin - Increases the prothrombin time.
    • Theophylline - Increases plasma concentration.

4. Always keep a list of all the medications you take, and share with your doctor or pharmacist to know health questions or concerns.

5. Ask your doctor for additional medical advice, concerns, or more information about this medicine.

What Are the Common Brand or Trade Names of Montelukast?

The common brand or trade names of Montelukast are,

  • Singulair Chew.
  • Astham.
  • Emlucast.
  • Glemont.
  • Montair.
  • Montek.
  • Montelast.
  • Monti.
  • Moto-10.
  • Odimont.
  • Romilast.
  • Ventair.

Frequently Asked Questions


What Is the Use of Montelukast?

Montelukast falls under the category of antihistamines. It is also known as an anti-allergic medication. It is used to treat mild cases of asthma. It gives relief from breathing problems, constant sneezing, and seasonal allergies. 


Can Montelukast Be Used to Treat Cough?

Continuous cough is caused due to a substance called leukotrienes. Montelukast is known to be effective against leukotrienes. Hence, montelukast can be prescribed to treat persistent cough. It also helps treat coughs that may be caused due to seasonal allergies. 


Why Is Montelukast Prescribed at Night?

Most cases of montelukast are prescribed at night. However, it can be taken in the morning, also. It depends on the prescription of a doctor. When montelukast is prescribed to treat allergies, it is generally prescribed in the evening. This is done to prevent allergy flare-ups in the night and morning.


Is Montelukast a Form of Steroid?

Montelukast does not come under the classification of steroids. Montelukast is an anti- histamine medication. It falls under the category of leukotriene receptor antagonists. It acts on the chemical substances known as leukotriene antagonists, preventing the airway from narrowing.


Can Montelukast Treat Phlegmatic Cough?

Phlegmatic cough occurs as a result of infection. This infection could be caused due to various viral or bacterial organisms. Montelukast is not effective in treating this type of cough with phlegm. It helps to cure coughs that are caused due to various allergies. 


Is Montelukast Used to Treat Cold?

Montelukast is not used to treat all forms of cold. It is used to treat only colds due to allergies. Conditions such as allergic rhinitis have symptoms such as sneezing, stuffy nose, and itching of the nose and eyes. Montelukast is used to treat such conditions. 


Are Montelukast and Cetirizine the same?

Cetrizine and Montelukast both belong to the family of antihistamines. They treat cold symptoms such as running nose, sneezing, and stuffy nose. However, the usage of Montelukast is more specific than that of Cetirizine. 


How Does Montelukast Help the Lungs?

Montelukast is used to help relieve inflammation of the upper respiratory system. This inflammation can be caused due to allergic reactions to various allergens. It also prevents the narrowing of the airways due to allergic secretion. 


Does Montelukast Cause Any Damage to the Liver?

Montelukast is a medication that belongs to the class of antihistamines. Montelukast helps to treat symptoms of allergy such as sneezing, running nose, and wheezing. When used to treat chronic conditions, there are few cases of damage to the liver. But damage to the liver is very rare. 


Does Montelukast Give Immediate Effect?

Yes, montelukast is a leukotriene inhibitor that starts giving results as soon as administered. For the medication to show complete effect, it may take a week’s time. However, if montelukast is taken to prevent exercise induced asthma, it should be taken at least two hours prior to the requirement. 
Dr. Penchilaprasad Kandikattu
Dr. Penchilaprasad Kandikattu

Internal Medicine


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