Singulair (Montelukast)

Written by WebMD Editorial Contributor, Marijke Vroomen Durning, RN
Medically Reviewed by Shruthi N, MD on October 15, 2024
6 min read

Singulair is the brand name for the drug montelukast. It’s an oral prescription medication that can prevent or reduce acute asthma attacks in adults and children over 12 months old. It’s available in pill form or in granules, which may be easier for children or adults who have trouble swallowing pills. Singulair can also be used to help relieve allergy symptoms. 

 

 

Singulair is prescribed to help manage asthma and/or allergies.

Asthma

People with asthma might take Singulair to prevent asthma symptoms. It can help reduce the number of acute asthma attacks and make them less severe. Singulair is not a rescue medication that you might take while you are having an asthma attack. It shouldn’t be relied upon in an emergency.  

Allergies

If you have allergic rhinitis (hay fever) or other seasonal allergies, your doctor may prescribe Singulair to help relieve the sneezing, a runny nose, itching, or wheezing. If you have hives (urticaria) for longer than six weeks without relief, your doctor might recommend that you try Singulair as well.

When you have an asthma attack or your allergy symptoms flare up, your body releases chemicals called leukotrienes. These chemicals increase inflammation in your body, which can cause symptoms like a stuffy nose. The leukotrienes can also cause bronchoconstriction – tightening of the tiny tubes in your lungs. These are called bronchioles. This tightening up makes it hard for air to pass through, causing wheezing and difficulty breathing. Singulair is a leukotriene modifier. It blocks the effects of leukotrienes.

Singulair can cause mild side effects, and it can also cause serious ones. 

These are the common side effects, which often go away on their own. If these are severe or don’t go away, tell your doctor. If you’re having any uncomfortable symptoms that aren’t on this list but started after you began taking Singulair, contact your doctor as soon as possible. They could be side effects too.

  • Upper respiratory infections (like colds, influenza, and sinus infections)
  • Sore throat
  • Cough
  • Stomach pain
  • Diarrhea
  • Ear ache or ear infection
  • Runny nose
  • Body aches/pain
  • Dry or sore throat
  • Loss of voice
  • Tender, swollen glands in your neck
  • Changes in your voice
  • Constipation
  • Irregular heart beat
  • Difficulty sleeping

If you have any of these side effects, call your doctor right away:

  • Blistering, peeling, or shedding skin
  • Numbness or pins and needles in your arms or legs
  • Swelling in your sinuses

If your child is taking Singulair and has ear pain or a fever, call their doctor right away.

If you have any of these more serious side effects, seek emergency help or call 911:

  • Difficulty swallowing
  • Difficulty breathing
  • Itching, swelling, or puffiness around your eyes, lips, face, or tongue
  • Yellowing of the eyes or skin

The FDA has issued a special warning about Singulair because some people have had serious mental health issues after taking the drug. If you have any suicidal thoughts or thoughts of self-harm, this is a medical emergency. Call 911 or have someone take you to an emergency department.

If you are taking Singulair and have any of these symptoms, contact your doctor right away:

  • Agitation
  • Aggressive behavior or hostility
  • Difficulty concentrating or paying attention
  • Having bad or vivid dreams
  • Depression
  • Disorientation or confusion
  • Anxiety
  • Hallucinations
  • Crankiness, restlessness
  • Problems with memory
  • Obsessive-compulsive symptoms
  • Sleepwalking
  • Stuttering
  • Trouble sleeping
  • Uncontrolled muscle movements

Not everyone can safely take Singulair. It might not be the right drug if you:

  • Currently have or have had liver disease
  • Have allergic reactions or any unusual reactions to any medications (such aspirin or NSAIDs), foods, dyes, or preservatives
  • Are pregnant or are trying to get pregnant (If you are taking Singulair and you become pregnant, tell your doctor right away.)
  • Are breastfeeding
  • Have phenylketonuria (PKU), a rare disorder that requires you to follow a very strict diet from birth to prevent brain damage
  • Have a history of depression or other mental health conditions

Children can take Singulair if prescribed. Parents and guardians should watch for signs of mental health changes, as well as other side effects. Psychiatric side effects seem to be more common among children than adults.

Singulair drug interactions

Singulair can interact with other medications, over-the-counter products, and supplements, so it’s important that your doctor know what you are taking before prescribing Singulair and that all other doctors you might see know that you are taking this drug. You still might have to take the drugs together, but if your doctor is aware, they can change the doses or how often you take them to lessen the risk of interactions. Some of the drugs that may interact with Singulair are:

You should also avoid drinking grapefruit juice while taking Singulair.

 

Some people who stop taking Singulair report having a hard time with intense and possibly life-threatening withdrawal symptoms, including:

  • Flu-like symptoms
  • Anxiety
  • Depression
  • Insomnia
  • Suicidal thoughts and actions

For this reason, with the exception of severe allergic or life-threatening side effects, you shouldn’t stop taking Singulair without consulting your doctor first. 

 

Since not everyone can or wants to take Singulair, you might be thinking of asking about alternatives to the drug. There are two other medications that are leukotriene modifiers like Singulair. They are:

Singulair is an oral medication that you can take if you have asthma or an allergy like hay fever. It can make asthma attacks or allergic reactions happen less often and can make them less severe. But the drug can cause serious side effects, so you must work with your doctor, making sure to report any side effects you have. Also, Singulair has been connected to serious mental problems, including suicidal thoughts and actions. If you have suicidal thoughts, this is a medical emergency. Call 911 or go to the closest emergency department right away.

What is montelukast used for?

Montelukast (Singulair) is used to reduce the number of asthma attacks you have and make them less severe. It can also be used to help relieve allergy symptoms.

What is the most common side effect of Singulair?

There are several side effects that could occur if you take Singulair, but there is no one common one that happens more often than others. The most serious side effects you should be aware of include allergic reactions (difficulty breathing or a swollen tongue, for example) and those related to your mental health, like thoughts of suicide.

Is it OK to take Singulair every day for allergies?

If your doctor prescribes Singulair, you should take it as directed, which for allergies is typically once a day in the evening.

What should I avoid while taking montelukast?

You should avoid drinking grapefruit juice while taking montelukast (Singulair)

Is Singulair available over the counter?

You can only get prescription Singulair in the U.S. It is not an over-the-counter product.

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