Pronunciation: zye LOO ton

Brand: Zyflo

Zyflo CR

slide 1 of 2, Zyflo CR,

600 mg, oval, white, imprinted with CT2

Image of Zyflo CR
slide 1 of 2


slide 2 of 2, Zileuton,

600 mg, oval, white, imprinted with P723

Image of Zileuton
slide 2 of 2

What is the most important information I should know about zileuton?

Zileuton is not a fast-acting rescue medicine for asthma attacks. Seek medical attention if your breathing problems get worse quickly, or if you think your medications are not working.

Call your doctor right away if you have any changes in behavior or sleep problems.

What is zileuton?

Zileuton is used to prevent asthma attacks and for long-term management of asthma in adults and children at least 12 years old.

Zileuton may also be used for purposes not listed in this medication guide.

What should I discuss with my healthcare provider before taking zileuton?

You should not use zileuton if you are allergic to it, or if you have:

  • liver disease; or
  • very high liver enzymes on a blood test.

Tell your doctor if you have ever had:

  • liver problems, dark urine, or jaundice (yellow eyes or skin); or
  • if you drink large amounts of alcohol.

Tell your doctor if you are pregnant or breastfeeding.

If you are pregnant, your name may be listed on a pregnancy registry to track the effects of zileuton on the baby.

How should I take zileuton?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Zileuton tablets are usually taken 4 times a day at the same times each day, with or without food. If you cannot swallow a tablet whole, split it in half and take one half at a time.

Zileuton extended-release tablets are usually taken twice daily, within 1 hour after your morning and evening meals.

Swallow the extended-release tablet whole and do not crush, chew, or break it.

Your symptoms may not improve for several days or a few weeks. Keep using this medicine even after you have no symptoms (a sign that the medicine is working).

Zileuton is not a fast-acting rescue medicine for asthma attacks. Seek medical attention if your breathing problems get worse quickly, or if you think your medications are not working.

Do not change your dose or stop using asthma medication without your doctor's advice.

You will need frequent blood tests to check your liver function.

Store at room temperature away from moisture, heat, and light.

What happens if I miss a dose?

Skip the missed dose and take your next dose at the regular time. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking zileuton?

Avoid drinking alcohol. It may increase your risk of liver damage.

What are the possible side effects of zileuton?

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • worsening asthma symptoms;
  • sleep problems;
  • changes in behavior or sleep problems; or
  • liver problems --nausea, stomach pain (upper right side), tiredness, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common side effects may include:

  • upset stomach, diarrhea, nausea, or stomach pain;
  • muscle aches;
  • headache; or
  • runny or stuffy nose, sinus pain, sneezing, sore throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect zileuton?

When you start or stop taking zileuton, your doctor may need to adjust the doses of other medicines you use on a regular basis, especially:

  • propranolol;
  • theophylline; or
  • warfarin, Coumadin, Jantoven.

This list is not complete. Other drugs may affect zileuton, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Where can I get more information?

Your pharmacist can provide more information about zileuton.

This information does not replace the advice of a doctor. Healthwise, Incorporated, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content.