Zafirlukast (By mouth)
Treats asthma and prevents asthma attacks.
When This Medicine Should Not Be Used
How to Use This Medicine
- Take your medicine as directed.
- Take this medicine on an empty stomach at least 1 hour before or 2 hours after a meal.
- Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
- Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
- Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
Drugs and Foods to Avoid
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
- Some foods and medicines can affect how zafirlukast works. Tell your doctor if you are using any of the following:
- Steroid medicine
- Blood thinner (such as warfarin)
Warnings While Using This Medicine
- Tell your doctor if you are pregnant or breastfeeding, or if you have liver disease.
- This medicine will not stop an asthma attack that has already started. Your doctor may prescribe another medicine for you to use in case of an acute asthma attack.
- This medicine may cause the following problems:
- Liver problems
- Churg-Strauss syndrome
- If you use a corticosteroid medicine to control your asthma, keep using it as instructed by your doctor.
- If any of your asthma medicines do not seem to be working as well as usual, call your doctor right away. Do not change your doses or stop using your medicines without asking your doctor.
- Call your doctor if your symptoms do not improve or if they get worse.
- Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
- Keep all medicine out of the reach of children. Never share your medicine with anyone.
Possible Side Effects While Using This Medicine
Call your doctor right away if you notice any of these side effects:
- Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
- Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
- Numbness in your arms or legs, unexplained fever and chills, rash
- Mood or behavior changes, depression, trouble sleeping
- Worse asthma or allergy symptoms (such as increased wheezing, trouble breathing, or tightness in the chest)
If you notice other side effects that you think are caused by this medicine, tell your doctor
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088
- Last reviewed on 7/4/2015
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