Brand Name(s):

  • Singulair®

WHY is this medicine prescribed?

Montelukast is used to prevent wheezing, difficulty breathing, chest tightness, and coughing caused by asthma. Montelukast is also used to prevent bronchospasm (breathing difficulties) during exercise. Montelukast is also used to treat the symptoms of seasonal (occurs only at certain times of the year), and perennial (occurs all year round) allergic rhinitis (a condition associated with sneezing and stuffy, runny or itchy nose). Montelukast is in a class of medications called leukotriene receptor antagonists (LTRAs). It works by blocking the action of substances in the body that cause the symptoms of asthma and allergic rhinitis.

HOW should this medicine be used?

Montelukast comes as a tablet, a chewable tablet, and granules to take by mouth. Montelukast is usually taken once a day with or without food. When montelukast is used to treat asthma, it should be taken in the evening. When montelukast is used to prevent breathing difficulties during exercise, it should be taken at least 2 hours before exercise. If you are taking montelukast once a day on a regular basis, you should not take an additional dose before exercising. When montelukast is used to treat allergic rhinitis, it may be taken at any time of day. Take montelukast at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take montelukast exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

If you are giving the granules to your child, you should not open the foil pouch until your child is ready to take the medication. There are several ways that you can give the granules to your child, so choose the one that works best for you and your child. You may pour all of the granules directly from the packet into your child's mouth to be swallowed immediately. You may also pour the entire packet of granules onto a clean spoon and place the spoonful of medication in your child's mouth. If you prefer, you may mix the entire packet of granules in 1 teaspoon (5 mL) of cold or room temperature baby formula, breastmilk, applesauce, soft carrots, ice cream, or rice. You should not mix the granules with any other foods or liquids, but your child may drink any liquid right after he or she takes the granules. If you mix the granules with one of the allowed foods or drinks, use the mixtures within 15 minutes. Do not store unused mixtures of food, formula, or breast milk and the medication.

Do not use montelukast to treat a sudden attack of asthma symptoms. Your doctor will prescribe a short-acting inhaler to use during attacks. Talk to your doctor about how to treat symptoms of a sudden asthma attack. If your asthma symptoms get worse or if you have asthma attacks more often, be sure to call your doctor.

If you are taking montelukast to treat asthma, continue to take or use all other medications that your doctor has prescribed to treat your asthma. Do not stop taking any of your medications or change the doses of any of your medications unless your doctor tells you that you should. If your asthma is made worse by aspirin, do not take aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) during your treatment with montelukast.

Montelukast controls the symptoms of asthma and allergic rhinitis but does not cure these conditions. Continue to take montelukast even if you feel well. Do not stop taking montelukast without talking to your doctor.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Are there OTHER USES for this medicine?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before taking montelukast,

  • tell your doctor and pharmacist if you are allergic to montelukast or any other medications.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention phenobarbital and rifampin (Rifadin, Rimactane). Your doctor may need to change the doses of your medications or monitor you more carefully for side effects.
  • tell your doctor if you have or have ever had liver disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking montelukast, call your doctor.
  • you should know that your mental health may change in unexpected ways while you are taking montelukast. You should call your doctor right away if you experience any of the following symptoms: agitation, aggressive behavior, anxiety, irritability, unusual dreams, hallucinations (seeing things or hearing voices that do not exist), depression, difficulty falling asleep or staying sleep, restlessness, sleep walking, suicidal thoughts or actions (thinking about harming or killing yourself or planning or trying to do so), or tremor (uncontrollable shaking of a part of the body). Your doctor will decide if you should continue taking montelukast.
  • if you have phenylketonuria (PKU, an inherited condition in which a special diet must be followed to prevent mental retardation), you should know that the chewable tablets contain aspartame that forms phenylalanine.

What SPECIAL DIETARY instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do IF I FORGET to take a dose?

Skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one. Do not take more than one dose of montelukast in a 24 hour period.

What SIDE EFFECTS can this medicine cause?

Montelukast may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • headache
  • dizziness
  • heartburn
  • stomach pain
  • tiredness

Some side effects can be serious. If you experience any of the following symptoms or those listed in the SPECIAL PRECAUTIONS section, call your doctor immediately:

  • difficulty breathing or swallowing
  • swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
  • hoarseness
  • itching
  • rash
  • hives
  • fever
  • flu-like symptoms
  • pins and needles or numbness in the arms or legs
  • pain and swelling of the sinuses

Montelukast may cause other side effects. Call your doctor if you have any unusual problems while you are taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

What should I do in case of OVERDOSE?

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Symptoms of overdose may include:

  • stomach pain
  • sleepiness
  • thirst
  • headache
  • vomiting
  • restlessness or agitation

What OTHER INFORMATION should I know?

Keep all appointments with your doctor.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: December 1, 2009.