Please read this page carefully before you start taking ZYFLO CR™. Also, you could bookmark this page and come back to it as you need to refresh your memory.

This page provides important information about taking ZYFLO CR. It is not meant to take the place of your doctor's specific instructions. Talk to your doctor if you have any questions about ZYFLO CR. Your doctor or pharmacist can also provide you with additional information about ZYFLO CR.

The most important things to remember are to take all your doses of ZYFLO CR every day and to make sure that you return to your doctor's office for scheduled liver enzyme tests. You should also know that you should seek medical help immediately if you need more "puffs" of your bronchodilator inhaler than normal or if you use the maximum number of "puffs" prescribed for one 24-hour period. These could be signs of worsening asthma, which means that your asthma therapy may need to be changed.

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, which contains the active ingredient zileuton, blocks the formation of certain chemicals (leukotrienes) that may contribute to your asthma symptoms.

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.

You should not take ZYFLO CR if you have active liver disease or have liver enzymes (substances released by the liver) that are elevated, or if you have ever had an allergic reaction to this medicine.

Your doctor will determine if it is safe for you to take 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.
• drink alcohol. Tell your health care provider how much and how often you drink alcohol.
• have difficulty swallowing pills
• 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.
• are breastfeeding. 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 breast feed. You should not do both.

Tell your health care provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. ZYFLO CR and other medicines may affect each other causing side effects. Your health care provider may need to adjust the doses of certain medicines while you are taking ZYFLO CR. Talk with your health care provider before starting or stopping any prescription or nonprescription medicine.

Know the medicines you take. Keep a list of your medicines and show it to your health care provider and pharmacist when you get a new medicine.

• Take ZYFLO CR exactly as prescribed by your health care provider. Do not decrease the dose of ZYFLO CR or stop taking the medicine without talking to your health care provider first, even if you have no asthma symptoms.
• Take two ZYFLO CR tablets two times each day within one hour after your morning and evening meals.
• Swallow ZYFLO CR whole. Do not chew, cut or crush ZYFLO CR tablets. Tell your health care provider if you cannot swallow the tablets whole.
• Follow your health care provider's instructions for what to do if you get sudden symptoms of an asthma attack. You can continue taking ZYFLO CR during asthma attacks.
• Get medical help right away if you need to use your rescue medicine more often than usual or if you use the highest number of "puffs" prescribed for one 24-hour period. These could be signs that your asthma is getting worse. This means that your asthma therapy may need to be changed.
• Keep taking your other asthma medicines as directed while taking ZYFLO CR.
• If you miss a dose, just take your next scheduled dose when it is due. Do not double the dose.
• If you take too much ZYFLO CR, call your health care provider or a Poison Control Center right away.

ZYFLO CR can cause serious side effects.

Liver problems. Liver function enzymes and bilirubin can increase while taking ZYFLO CR, and severe liver injury can occur.

• Keep all of your health care provider's appointments and be sure to follow all of your health care provider's instructions. Have your blood tests done as ordered to check your liver enzymes.
• 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
  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.

Keep ZYFLO CR and all medicines out of the reach of children. In case of an accidental overdose, call your doctor or a Poison Control Center immediately.

Protect ZYFLO CR from light and replace the child-resistant cap each time after use. Store ZYFLO CR between 68° - 77°F (20° - 25°C).

Learn more about asthma, its causes and how it is treated.