April 27, 2017
Recommended Topic Related To:

Zyflo CR

"NEW YORK (Reuters Health) - New research in mice and human lung tissue suggests soluble ADAM33 (sADAM33) may prompt airway remodeling and boost allergic airway inflammation, making it a possible therapeutic target.

As Dr. Hans Michael"...


Zyflo CR

(zileuton) Extended-Release Tablets


Zileuton is an orally active inhibitor of 5-lipoxygenase, the enzyme that catalyzes the formation of leukotrienes from arachidonic acid. Zileuton has the chemical name (±)-1-(1-Benzo[b]thien-2-ylethyl)-1-hydroxyurea and the following chemical structure:

  (zileuton) Structural Formula Illustration

zileuton Zileuton has the molecular formula C11H12N2O2S and a molecular weight of 236.29. It is a racemic mixture (50:50) of R(+) and S(-) enantiomers. Zileuton is a practically odorless, white, crystalline powder that is soluble in methanol and ethanol, slightly soluble in acetonitrile, and practically insoluble in water and hexane. The melting point ranges from 144.2°C to 145.2°C

ZYFLO CR (zileuton) extended-release tablets for oral administration are triple-layer tablets comprised of an immediate-release layer, a middle (barrier) layer, and an extended-release layer. ZYFLO CR tablets are oblong, film-coated tablets with one red layer between two white layers, debossed on one side with "CT2". Each tablet contains 600 mg of zileuton and the following inactive ingredients: crospovidone, ferric oxide, glyceryl behenate, hydroxypropyl cellulose, hypromellose, magnesium stearate, mannitol, microcrystalline cellulose, povidone, pregelatinized starch, propylene glycol, sodium starch glycolate, and talc.

What are the possible side effects of zileuton (Zyflo, Zyflo CR)?

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

Call your doctor at once if you have a serious side effect such as:

  • nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
  • skin rash, bruising, severe tingling, numbness, pain, muscle weakness;
  • mood or behavior changes, anxiety, depression, or thoughts about suicide or hurting yourself; or
  • worsening asthma...

Read All Potential Side Effects and See Pictures of Zyflo CR »

What are the precautions when taking zileuton extended release tablets (Zyflo CR)?

Before taking zileuton, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease, alcohol use.

This medication may cause liver problems. Limit alcoholic beverages because alcohol may increase your risk for liver problems. Ask your doctor or pharmacist for more information.

Older women may be more sensitive to the effects of the drug, especially liver problems.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with...

Read All Potential Precautions of Zyflo CR »

Last reviewed on RxList: 11/29/2016
This monograph has been modified to include the generic and brand name in many instances.

Zyflo CR - User Reviews

Zyflo CR User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication Zyflo CR sorted by most helpful. Patient Discussions FAQs

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Allergies & Asthma

Improve treatments & prevent attacks.