Montelukast is used to treat and prevent asthma. It will decrease the symptoms and the number of acute asthma attacks. However, this medicine should not be used to relieve an asthma attack that has already started. This medicine is also used to prevent exercise-induced bronchoconstriction (EIB), and treat symptoms of seasonal (short-term) or perennial (long-term) allergies, such as sneezing, runny nose, itching, or wheezing.

This medicine is available only with your doctor's prescription.

Use this medicine only as directed by your doctor. Do not use more of it and do not use it more often, unless otherwise directed by your doctor.

This medicine comes with a patient information insert. Read and follow the instructions in the insert carefully. Ask your doctor if you have any questions.

Montelukast is used to prevent asthma attacks. It is not used to relieve an attack that has already started. For relief of an asthma attack that has already started, you should use another inhaled medicine. If you do not have an inhaled medicine to use for an attack, or if you have any questions about this, check with your doctor.

To work properly, montelukast must be taken at the same time each day, even if your asthma seems better.

You may take this medicine with or without food.

For patients taking the oral granules:

-> Open the packet until you are ready to use it.
-> The oral granules may either be swallowed whole, or dissolved in 1 teaspoonful (5 mL) of cold or room temperature baby formula or breast milk, or mixed with a               spoonful of soft food, such as applesauce, carrots, rice, or ice cream. The oral granules should not be chewed. Do not mix this medicine with any other liquid other           than baby formula or breast milk.
-> The mixed medicine must be given within 15 minutes and must not be stored for future use.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common

Abdominal or stomach pain

bloody nose

flu-like symptoms

general feeling of discomfort or illness

headache

joint pain

pain or tenderness around the eyes and cheekbones

shortness of breath or troubled breathing

sweating

tightness of the chest

trouble with swallowing

unusual tiredness or weakness

Rare

Pus in the urine

Incidence not known

Agitation

anxiety

attempts at killing oneself

breathing problems

confusion about identity, place, and time

constipation

fast, irregular, pounding, or racing heartbeat or pulse

feeling sad or empty

hives or welts

indigestion

itching, puffiness, or swelling of the eyelids or around the eyes, face, lips, or tongue

lack of appetite

pains in the stomach, side, or abdomen, possibly moving to the back

redness of the skin

shaking or trembling of the hands or feet

trouble with concentrating

unable to sleep

unpleasant breath odor

upper right abdominal or stomach pain

vomiting of blood

yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Acid or sour stomach

belching

blurred vision

change in near or distance vision

dental pain

earache

heartburn

lack or loss of strength

pain

skin rash, encrusted, scaly and oozing

stomach discomfort, upset, or pain

Incidence not known

Burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings

dreams that are unusual

increased tendency to bleed

large, flat, blue or purplish patches on the skin

muscle aching or cramping

sleepiness

swollen joints

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

If you will be taking this medicine for a long time, it is very important that your doctor check you or your child at regular visits. This will allow your doctor to see if the medicine is working properly and to check for any unwanted effects.

You may be taking other medicines for asthma together with montelukast. Do not stop taking these medicines and do not reduce the dose, even if your asthma seems better, unless you or your child are told to do so by your doctor.

Talk to your doctor or get medical care right away if:

Your or your child's symptoms do not improve after using this medicine or if they become worse.
Your short-acting inhaler does not seem to be working as well as usual and you need to use it more often.
Montelukast may cause some people to be agitated, disoriented, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. Report any unusual thoughts or behaviors that trouble you or your child, especially if they are new or get worse quickly. Make sure the doctor knows if you or your child have trouble sleeping, get upset easily, or start to act reckless. Also tell the doctor if you or your child have sudden or strong feelings, such as feeling nervous, angry, restless, violent, or scared.

This medicine may increase certain white blood cells (eosinophils) and may cause systemic vasculitis. Check with your doctor right away if you have a feeling of numbness in your arms or legs, flu-like symptoms, rash, or pain or swelling of the sinuses.