Call your doctor right away if you feel that this medicine is not working as well as usual, or if it makes your condition worse. If it seems like you need to use more of any of your medications in a 24-hour period, talk with your doctor.
Zafirlukast is a leukotriene (loo-koe-TRY-een) inhibitor. Leukotrienes are chemicals your body releases when you breathe in an allergen (such as pollen). These chemicals cause swelling in your lungs and tightening of the muscles around your airways, which can result in asthma symptoms.
Zafirlukast is used to treat and prevent asthma attacks in adults and children as young as 5 years old.
Do not give this medication to a child without a doctor's advice.Zafirlukast may also be used for other purposes not listed in this medication guide.
Before using zafirlukast, tell your doctor if you are allergic to any drugs (especially aspirin), or if you have liver disease. You may not be able to use zafirlukast, or you may need dosage adjustments or special tests during treatment.
The chewable tablet form of this medication may contain up to 0.842 milligrams of phenylalanine. Talk to your doctor before using this form of zafirlukast if you have phenylketonuria (PKU).
FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Zafirlukast can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label.
Zafirlukast is usually taken once daily in the evening for prevention of asthma or allergy symptoms. Follow your doctor's instructions.
Take zafirlukast on an empty stomach, at least 1 hour before or 2 hours after a meal. Do not use zafirlukast to treat an asthma attack that has already begun. It will not work fast enough to reverse your symptoms. Use only a fast-acting inhalation medication to treat an asthma attack. Talk with your doctor if any of your asthma medications do not seem to work as well in treating or preventing asthma attacks. For best results, keep using zafirlukast as directed. Talk with your doctor if your symptoms do not improve after several weeks of treatment.Asthma is often treated with a combination of different drugs. To best treat your condition, use all of your medications as directed by your doctor. Be sure to read the medication guide or patient instructions provided with each of your medications. Do not change your doses or medication schedule without advice from your doctor, even if you have no asthma symptoms.
Call your doctor right away if you feel that this medicine is not working as well as usual, or if it makes your condition worse. If it seems like you need to use more of any of your medications in a 24-hour period, talk with your doctor.
Store zafirlukast at room temperature away from moisture and heat.![]() |
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