Singulair

Medically Reviewed by HaVy Ngo, Pharm.D.

Last Reviewed: Jun 07, 2022

Warnings


What are the risks of taking Singulair (montelukast)?



Singulair (montelukast) can cause serious health problems, especially in certain high-risk patients.

Other risks of Singulair use include:
  • Rarely, Singulair can cause mental changes in children and adults. Symptoms may include irritability, memory problems, hallucinations, and suicidal ideation. Patients with no prior history of mental health problems can also develop these symptoms. If you experience mental changes on Singulair, please talk to your doctor immediately for medical advice. 

  • Singulair is not a treatment for acute asthma as it will not treat sudden asthma attacks. You should use your rescue inhaler if you experience trouble breathing. Talk to your doctor if Singulair does not improve the frequency or severity of your asthma attacks or if it makes your asthma symptoms worse.

  • A rare complication of Singulair is an increase in the number of eosinophils (a type of white blood cell). This can cause symptoms such as patches of red rash on the lower legs and numbness as well as worsening asthma symptoms. Contact your health care provider immediately if you notice these symptoms.

  • Patients with an inherited medical condition called phenylketonuria have high levels of a substance called phenylalanine in their blood. Therefore, such individuals should not use Singulair chewable tablets because they contain phenylalanine.

Your doctor or pharmacist can discuss other treatments for asthma and allergies if you are at risk of complications from Singulair use.


What should I tell my doctor before starting Singulair (montelukast)?

Tell your health care professional about all your medical conditions, especially liver disease—Singulair tablets are not suitable for people with certain medical conditions.

Also, tell your doctor and pharmacy about all your medications, including over-the-counter medicines, dietary supplements, and herbal remedies. This can help avoid serious drug interactions.

Be sure to tell your doctor if you have previously had an allergic reaction to montelukast or any of the other ingredients in Singulair tablets, chewable tablets, or granules.

Tell your doctor if you are pregnant, planning a pregnancy, or breastfeeding. If you become pregnant while on Singulair, let your doctor know.

Please let your doctor know if you have phenylketonuria as chewable Singulair tablets contain aspartame that forms phenylalanine.

What precautions should I take while on Singulair (montelukast)?

Keep all appointments with your doctor or healthcare professional. 

Before starting Singulair, tell your doctor if you have a history of liver disease, phenylketonuria, or other medical conditions. 

The US Food and Drug Administration (FDA) has not assigned a pregnancy category for Singulair. Decades of studies have not shown a significant increase in major birth defects when Singulair is being used during pregnancy. However, it is important to inform your doctor if you are pregnant, plan to become pregnant, or are breastfeeding while you are taking Singulair or planning on taking it. 

Call 911 or go to the nearest emergency room if you experience signs and symptoms of an allergic reaction to Singulair, such as difficulty breathing, swelling of the face, hives, peeling skin, numbness, pins and needles.

What are Singulair (montelukast) interactions?

Taking Singulair with some other medications can affect how well it works. Drug interactions can also increase the risk of serious side effects. Your physician may change the dose of your medications or monitor you more carefully for side effects on certain combinations of medicines. 

Using Singulair with the following medications is not recommended but may be necessary for some patients:

There can also be interactions between Singulair and medicines such as:

This list does not describe all possible Singulair interactions. Provide your health care provider a complete list of your prescription and non-prescription medications, vitamins, dietary supplements, and herbal products. Also, tell your health care provider if you smoke, drink alcohol, or use recreational substances because some of these substances may cause serious health complications when used with prescription drugs.