1. Montelukast oral tablet is available as a brand-name drug and a generic drug. Brand name: Singulair.
  2. Montelukast comes in the form of a tablet that can be swallowed whole, or as a chewable tablet. It’s also available as granules that can be dissolved in liquid or soft food.
  3. Montelukast oral tablet is used to prevent and treat symptoms of asthma and seasonal or year-round allergies. It can also be used to prevent exercise-induced bronchoconstriction (EIB).

  • Appropriate use warning: You should not use this drug if you have a sudden asthma attack. Also, don’t use it to treat status asthmaticus. This is a severe asthma attack that doesn’t respond to treatment with an inhaler. It’s a medical emergency. This drug should also not be used in place of inhaled or oral corticosteroids for moderate persistent asthma with daily symptoms. You can take this drug in combination with corticosteroids.
  • Mental health problems warning: This drug may increase your risk of mental health problems. Symptoms can include agitation, aggressive behavior, hostility, anxiousness, depression, or confusion. They can also include vivid dreams, hallucinations, trouble sleeping, irritability, or suicidal thoughts or actions. If you or your child is taking this drug, watch for these symptoms. If you notice them, call your doctor right away.
  • Immune system problems warning: This drug may increase your risk of certain immune system problems. These include systemic eosinophilia with vasculitis, and Churg-Strauss syndrome. With this syndrome, there is an increase of white blood cells in your body. This can cause numbness in the arms or legs, or flu-like symptoms such as fever, muscle aches, or cold sweats.

Montelukast is a prescription drug. It comes as a tablet that can be swallowed whole, or as a chewable tablet. It’s also available as granules that can be dissolved in liquid or soft food.

Montelukast oral tablet is available as the brand-name drug Singulair. It’s also available as a generic drug. Generic drugs usually cost less than the brand-name version. In some cases, they may not be available in every strength or form as the brand-name drug.

This drug may be used as part of a combination therapy. This means you may need to take it with other medications.

Why it's used

Montelukast oral tablet is used to prevent and treat asthma. It’s also used to treat seasonal and year-round allergies.

Montelukast is also used to prevent exercise-induced bronchoconstriction (EIB). EIB occurs when the airways in the lungs narrow during or after exercise. This can cause shortness of breath, wheezing, or cough.

How it works

Montelukast belongs to a class of drugs called leukotriene receptor antagonists. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Leukotriene receptor antagonists help decrease inflammation and nasal congestion. This can help prevent reactions to triggers by keeping the airways to your lungs open. This helps improve symptoms of asthma as well as seasonal and year-round allergies. It also helps prevent breathing problems during or after exercise.

Montelukast oral tablet doesn’t cause drowsiness, but it can cause other side effects.

More common side effects

The more common side effects that can occur with use of montelukast include:

  • upper respiratory infection (infection in the nose or throat)
  • fever
  • headache
  • sore throat
  • cough
  • stomach pain
  • diarrhea
  • earache or ear infection
  • flu
  • runny nose
  • sinus infection
  • bed-wetting in children

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Behavior and mood changes. Symptoms can include:
    • feeling anxious
    • bad or vivid dreams
    • sleepwalking
    • confusion
    • agitation
    • restlessness
    • tremor
    • trouble sleeping
    • suicidal thoughts or actions
    • hallucinations (seeing or hearing things that aren’t really there)
  • Increase in eosinophils (white blood cells). Symptoms can include:
    • numbness in the arms or legs
    • flu-like symptoms such as fever, muscle aches, or cold sweats
  • Systemic vasculitis (inflamed blood vessels). Symptoms can include:
    • feeling of “pins and needles” or numbness in the arms or legs
    • flu-like symptoms such as fever, muscle aches, or cold sweats
    • severe pain and swelling of the sinuses
  • Increased bleeding. Symptoms can include:
    • bleeding under the skin
    • longer bleeding from cuts
    • blood in the urine or feces
  • Stevens-Johnson syndrome. This is a medical emergency. Symptoms can include:
    • swelling of the face or tongue
    • hives
    • skin pain
    • a purple or red rash
  • Uncontrolled muscle movements. Symptoms can include:
    • tics (muscle spasms)

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.

An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well. To help prevent interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking.

To find out how montelukast oral tablet might interact with something else you’re taking, talk to your doctor or pharmacist.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

This drug comes with several warnings.

Allergy warning

This drug can cause a severe allergic reaction. Symptoms can include:

  • swelling of the face, lips, tongue, and/or throat
  • trouble breathing
  • hives
  • itching

If you develop these symptoms, call 911 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

Warning for people with aspirin or NSAID allergy

If you have a sensitivity or allergy to aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs), you should continue to avoid these drugs while taking this drug. Sensitivity to these drugs may lead to tightening of your airways, and this drug may not fully treat these symptoms.

Warnings for other groups

For pregnant women: This drug is a category B pregnancy drug. That means two things:

  1. Studies of the drug in pregnant animals have not shown a risk to the fetus.
  2. There aren’t enough studies done in pregnant women to show if the drug poses a risk to the fetus.

Talk to your doctor if you’re pregnant or planning to become pregnant. This drug should be used only if the potential benefit justifies the potential risk.

For women who are breastfeeding: It is not known if this drug passes into breast milk or causes side effects in a child who is breastfed. Talk to your doctor if you breastfeed your child. You may need to decide whether to stop breastfeeding or stop taking this medication.

For seniors: The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, a higher amount of a drug stays in your body for a longer time. This raises your risk of side effects.

Asthma attack warning

  • Go to the emergency room if you have an asthma attack that is not relieved by using a rescue inhaler. Early signs of an asthma attack include cough, wheezing, losing your breath easily, or feeling short of breath. They also include feeling tired, having trouble sleeping, or having allergy symptoms (such as sneezing, runny nose, nasal congestion, or headache).

All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

Drug forms and strengths

Generic: Montelukast

  • Form: oral tablet
  • Strength: 10 mg
  • Form: chewable tablet
  • Strengths: 4 mg, 5 mg

Brand: Singulair

  • Form: oral tablet
  • Strength: 10 mg
  • Form: chewable tablet
  • Strengths: 4 mg, 5 mg

Dosage for asthma

Adult dosage (ages 15 years and older)

  • The typical dosage is one 10-mg tablet taken once daily in the evening.

Child dosage (ages 6–14 years)

  • The typical dosage is one 5-mg chewable tablet taken once daily in the evening.

Child dosage (ages 2–5 years)

  • The typical dosage is one 4-mg chewable tablet once daily in the evening.

Child dosage (ages 0–1 year)

  • It has not been determined that the use of montelukast oral tablet is safe or effective for asthma in children younger than 12 months.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, a higher amount of a drug stays in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dosage or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for allergic rhinitis (seasonal or perennial)

Adult dosage (ages 15 years and older)

  • The typical dosage is one 10-mg tablet taken once daily.

Child dosage (ages 6–14 years)

  • The typical dosage is one 5-mg chewable tablet taken once daily.

Child dosage (ages 2–5 years)

  • The typical dosage is one 4-mg chewable tablet or one packet of 4-mg oral granules once daily in the evening.

Child dosage (ages 0–1 year)

  • It has not been determined that the use of montelukast oral tablet is safe or effective for allergies in children younger than 12 months.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, a higher amount of a drug stays in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dosage or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for exercise-induced bronchoconstriction (EIB)

Adult dosage (ages 15 years and older)

  • The typical dosage is one 10-mg tablet taken 2 hours before exercise.

Child dosage (ages 6–14 years)

  • The typical dosage is one 5-mg chewable tablet taken 2 hours before exercise.

Child dosage (ages 0–5 years)

  • It has not been determined that the use of montelukast oral tablet is safe or effective for EIB in children younger than 12 months.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, a higher amount of a drug stays in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dosage or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Dosage warnings

  • If you have both asthma and allergic rhinitis, you should take only one dose of montelukast daily in the evening.
  • If you’re already taking montelukast for asthma or allergies, you should not take an extra dose to prevent EIB.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.

Montelukast oral tablet is used for long-term treatment. It comes with risks if you don’t take it as prescribed.

If you stop taking the drug suddenly or don’t take it at all: You increase your risk of more frequent and more severe asthma attacks. Asthma that is not treated can lead to increased lung damage.

If you have allergies, their symptoms may not be reduced. And exercise-related breathing problems may not be controlled.

If you miss doses or don’t take the drug on schedule: Your medication may not work as well.

If you take too much: You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:

  • pain in your abdomen (stomach area)
  • vomiting
  • trouble sleeping
  • thirst
  • headache
  • hyperactive behavior, such as extreme restlessness, tremors, twitching, or pacing

If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.

What to do if you miss a dose: Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

How to tell if the drug is working: You should notice a decrease in how frequent or severe your asthma attacks are. Or you should notice a decrease in your allergy or EIB symptoms.

Keep these considerations in mind if your doctor prescribes montelukast for you.

General

  • You can take this drug with or without food. Taking it with food may help to reduce upset stomach.
  • Take this drug at the time(s) recommended by your doctor.
  • Do not cut or crush the tablet.

Storage

  • Keep the tablets at room temperature between 68°F and 77°F (20°C and 25°C).
  • Keep this drug away from light.
  • Don’t store this medication in moist or damp areas, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t harm your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled container with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Self-management

Your doctor may suggest that you keep a diary of your asthma or allergy attacks. This can help your doctor track how well your medication is controlling your symptoms.

Clinical monitoring

Your doctor will monitor your health while you take this drug. They will check how well your asthma, allergy, or other breathing symptoms are controlled.

Prior authorization

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.