Montelukast is the generic form of the brand name drug Singulair. It’s used to treat symptoms of asthma in adults and children at least 12 months old.

Singulair is also given to prevent exercise-induced asthma in adults and children who are at least 6 years old. Additionally, the medicine is given to treat seasonal allergies in adults and kids 2 years or older and year-round allergies in adults and kids 6 months or older.

This medicine is in a class of drugs called leukotriene receptor antagonists. It works by blocking the action of inflammatory chemicals in your body that cause allergy and asthma symptoms.

The U.S. Food and Drug Administration (FDA) approved this medicine in 1998.

warnings

What is the most important information I should know about Singulair (Montelukast)?

You should not use montelukast if you are allergic to it.

Tell your doctor if you have ever had:

mental illness or psychosis; or
asthma, or a history of severe allergic reaction (sneezing, runny or stuffy nose, wheezing, shortness of breath) after taking aspirin or another NSAID.

The chewable tablet may contain phenylalanine and could be harmful if you have phenylketonuria (PKU).

Tell your doctor if you are pregnant or breastfeeding.

Do not give this medicine to a child without a doctor's advice.

Side Effects

What are the side effects of Singulair (Montelukast)?

Get emergency medical help if you have signs of an allergic reaction: hives, blisters, severe itching; difficult breathing; swelling of your face, lips, tongue, or throat.

Tell your doctor right away if you have signs of blood vessel inflammation: flu-like symptoms, severe sinus pain, a skin rash, numbness or a "pins and needles" feeling in your arms or legs.

Some people using montelukast have had new or worsening mental problems. Stop taking this medicine and call your doctor right away if you have unusual changes in mood or behavior, such as:

agitation, aggression, feeling restless or irritable;
anxiety, depression, confusion, problems with memory or attention;
stuttering, tremors, uncontrolled muscle movements;
suicidal thoughts or actions;
hallucinations, sleep problems, vivid, dreams, sleep-walking; or
compulsive or repetitive behaviors.

Common side effects may include:

stomach pain, diarrhea;
fever or other flu symptoms;
ear pain or full feeling, trouble hearing;
headache; or
cold symptoms such as runny or stuffy nose, sinus pain, cough, sore throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Dosage Guidelines & Tips

How to take Singulair (Montelukast)?

Use Singulair (Montelukast) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Montelukast is not a fast-acting rescue medicine for asthma attacks. Seek medical attention if your breathing problems get worse quickly, or if you think your medications are not working.

Montelukast is usually taken once every evening, with or without food.

For exercise-induced bronchoconstriction, take a single dose at least 2 hours before exercise, and do not take another dose for at least 24 hours.

Swallow the regular tablet whole, with a glass of water.

You must chew the chewable tablet before you swallow it.

Place the oral granules directly in your mouth and swallow, or mix them with applesauce, mashed carrots, rice, or ice cream. The granules may also be mixed with baby formula or breast milk. Do not use any other type of liquid. Use the mixture within 15 minutes. Do not save for later use.

If you also use an oral steroid medication, you should not stop using it suddenly. Follow your doctor's instructions about tapering your dose.

Do not change your dose or stop using asthma medication without your doctor's advice.

Store at room temperature away from moisture and heat. Do not open a packet of oral granules until you are ready to use the medicine.

What should I do if I missed a dose of Singulair (Montelukast)?

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.