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Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.





This medication is used to control chronic asthma to help decrease the number of asthma attacks. It is also used to treat hay fever (seasonal allergic rhinitis). This drug works by blocking substances in the body called leukotrienes. Blocking leukotrienes improves asthma and seasonal allergic rhinitis symptoms.

How To Use

Take this medicine as directed, generally once daily with or without food. If taking for asthma, take the medicine in the evening. If taking for hay fever (seasonal allergic rhinitis), take the medicine at about the same time each day (either morning or evening). If you are taking this drug for both asthma and hay fever, take the medicine in the evening. Keep taking this medicine every day, even during asthma attacks and periods when you have no asthma symptoms. The granules may be swallowed directly in the mouth or mixed with a spoonful of soft food at cold or room temperature before swallowing. The following soft foods may be used: applesauce, mashed carrots, rice, or ice cream. Swallow the entire spoonful of the mixture right away (within 15 minutes). Never store any granule/food mixture for later use. Throw away any unused portion. Do not put the granules in liquid. However, you may drink liquids after swallowing the granules or granules/food mixture. This drug does not relieve acute asthma attacks. Use your prescribed acute asthma attack medicines (and pre-exercise medicines for exercise-related asthma) as directed. Consult the doctor or pharmacist for specific advice on all drug therapy. Do not decrease or stop any asthma medicine unless instructed to do so by the doctor. Report promptly to the doctor or pharmacist any worsening of asthma symptoms, if your short-acting inhaler use increases or if use exceeds the 24 hour maximum prescribed by the doctor. This medicine may come with a patient information leaflet. Read it carefully. Ask your doctor, nurse, or pharmacist any questions that you may have about this medicine.

Side Effects

Unusual weakness, stomach upset, diarrhea, dizziness, cough, headache, nausea, vomiting, trouble sleeping, or mouth pain may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. Tell your doctor immediately if any of these unlikely but serious side effects occur: hallucinations, fever, persistent sore throat or earache, flu symptoms. Tell your doctor immediately if any of these highly unlikely but very serious side effects occur: stomach pain, muscle aches/cramps, irregular heartbeat, yellowing eyes and skin, numbness or tingling of the hands or feet, easy bruising or bleeding, swelling, seizures. An allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of an allergic reaction include: rash, itching, severe swelling, severe dizziness, trouble breathing. If you notice other effects not listed above, contact your doctor or pharmacist.


Before using this drug, tell your doctor or pharmacist your medical history, especially of: allergies (especially drug allergies), liver disease. Use of this medication in children under the age of 1 year is not recommended. This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. It is not known whether this drug is excreted into breast milk. Consult your doctor before breast-feeding.

Drug Interactions

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription products you may use, especially of: rifamycin antibiotics (e.g., rifampin), certain drugs which stimulate liver metabolism (e.g., phenytoin, phenobarbital, carbamazepine), other asthma drugs. Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include thirst, drowsiness, dilated pupils, increased muscle movements, or severe stomach pain.


Do not share this medication with others. Laboratory and/or medical test should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

Missed Dose

If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not "double-up" the dose to catch up.


Store at room temperature at 77 degrees F (25 degrees C) away from light and moisture. Brief storage between 59 and 86 degrees F (15-30 degrees C) is permitted. Do not store in bathroom. Keep all medicines away from children and pets.

Medical Alert

Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).