Zyflo

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Antiasthmatic agent; a leukotriene synthesis inhibitor.1 2 46

Asthma

Prevention and long-term symptomatic management of asthma; used as an alternative, but not preferred adjunctive therapy.1 45 46

In patients with mild persistent asthma, low-dose orally inhaled corticosteroids considered first-line agents for long-term control.21 28 29 39 45 47 Alternative agents, including certain leukotriene modifiers (i.e., montelukast, zafirlukast), may be used but are less effective than inhaled corticosteroids and are not preferred as initial therapy.39 45 47

In patients with moderate persistent asthma, low-dose inhaled corticosteroids with a long-acting inhaled β2-agonist bronchodilator (e.g., salmeterol, formoterol) or monotherapy with medium-dose inhaled corticosteroids preferred.39 45 However, the National Asthma Education and Prevention Program recommends that the beneficial effects of long-acting inhaled β2-agonists be weighed carefully against increased risk of severe asthma exacerbations and asthma-related deaths associated with daily use of such agents.45

Alternative agents, including certain leukotriene modifiers (i.e., montelukast, zafirlukast), can be added to a low dosage of inhaled corticosteroid for treatment of moderate persistent asthma, but these options are less effective.39 45 Considerations favoring combination with orally inhaled corticosteroids include intolerance to long-acting β2-adrenergic agonists, marked preference for oral therapy, and demonstration of superior responsiveness to these leukotriene modifiers.45

Not recommended for relief of acute bronchospasm; however, may continue therapy during acute asthma exacerbations.1 46 (See Acute Asthma under Cautions.)

Metabolized principally by CYP1A2, CYP2C9, and CYP3A4;1 46 may inhibit CYP1A and CYP3A.1 27 30

Specific Drugs

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

In the U.S.

• Zyflo
• Zyflo CR

Available Dosage Forms:

• Tablet
• Tablet, Extended Release

Therapeutic Class: Anti-Inflammatory

Pharmacologic Class: Leukotriene Pathway Inhibitor

For all patients taking this medicine:

• If you have an allergy to zileuton or any other part of Zyflo.
• If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
• If you have any of these health problems: Active liver disease or a rise in liver enzymes.
• If you are taking terfenadine.
• If you are breast-feeding or plan to breast-feed.

Children:

• If your child is younger than 12 years of age. Do not give this medicine to a child younger than 12 years of age.

This is not a list of all drugs or health problems that interact with Zyflo.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this medicine with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Headache.
• Upset stomach.
• Belly pain or heartburn.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

Zyflo tablets are contraindicated in patients with:

• Active liver disease or transaminase elevations greater than or equal to three times the upper limit of normal (≥3xULN) (see PRECAUTIONS, Hepatic).
• Hypersensitivity to zileuton or any of its inactive ingredients.

Applies to zileuton: oral tablet, oral tablet extended release

Along with its needed effects, zileuton (the active ingredient contained in Zyflo) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking zileuton:

• Flu-like symptoms
• itching
• right upper stomach pain
• unusual tiredness or weakness
• yellow eyes or skin

• Attack, assault, or force
• attempts at killing oneself
• discouragement
• dry mouth
• fear or nervousness
• feeling sad or empty
• hyperventilation
• irregular heartbeats
• irritability
• lack of appetite
• loss of interest or pleasure
• restlessness
• seeing, hearing, or feeling things that are not there
• shakiness in the legs, arms, hands, or feet
• shortness of breath
• sleeplessness
• tiredness
• trembling or shaking of the hands or feet
• trouble with concentrating
• trouble with sleeping
• unable to sleep

Some side effects of zileuton may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

• Cough
• fever
• headache
• nausea
• pain or tenderness around the eyes and cheekbones
• stuffy or runny nose
• tightness of the chest or wheezing
• troubled breathing
• upset stomach

• Abdominal or stomach pain
• sore throat
• weakness