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About ZYFLO CR (zileuton)
ZYFLO CR is a medicine that is used to prevent asthma attacks and for long-term management of asthma in adults and children 12 years of age and older. ZYFLO CR blocks the production of leukotrienes. Leukotrienes are substances that may contribute to your asthma.
ZYFLO CR is not a rescue medicine (it is not a bronchodilator) and should not be used if you need relief right away for an asthma attack.
Important Patient Safety Information
Do not take ZYFLO CR if you have active liver disease, repeated blood tests showing elevated liver enzymes (substances released by the liver) or have ever had an allergic reaction to ZYFLO CR or any of the ingredients in ZYFLO CR.
ZYFLO CR may not be right for you. Tell your health care provider if you have ever had liver problems, including hepatitis, jaundice (yellow eyes or skin), or dark urine.
Tell your health care provider how much and how often you drink alcohol.
Tell your health care provider if you are pregnant or planning to become pregnant. It is not known if ZYFLO CR will harm your unborn baby. Do not take ZYFLO CR during pregnancy unless you and your health care provider decide that taking the medicine is more important than the possible risk to your unborn baby. It is not known if ZYFLO CR passes into your breast milk. You and your health care provider should decide if you will take ZYFLO CR or breastfeed. You should not do both.
Tell your health care provider if you have difficulty swallowing pills and about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements.
ZYFLO CR can cause serious side effects including liver problems. Liver function enzymes and bilirubin can increase while taking ZYFLO CR and severe liver injury can occur. Have your blood tests done as ordered to check your liver enzymes.
In addition, tell your healthcare provider if you have any sleep problems or changes in behavior while taking ZYFLO CR.
Tell your health care provider right away if you get any of the following signs or symptoms: pain on the right side of your abdomen (stomach area), nausea, tiredness, lack of energy, itching, yellow skin or yellow color in the whites of your eyes, dark urine, or “flu-like” symptoms.
Some of the most common side effects are nose and throat irritation, sinusitis, upper respiratory infection, throat pain, headache, muscle aches, nausea, and diarrhea.
Allergic reactions can happen while taking ZYFLO CR. Tell your health care provider right away if you get any of the following signs or symptoms: rash or hives.
Tell your health care provider if you have any new or unusual symptoms that bother you or do not go away while taking ZYFLO CR.
These are not all of the possible side effects of ZYFLO CR. For more information, ask your health care provider or pharmacist.
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.
For additional safety information, please see Full Prescribing Information and Patient Product Information.