Zileuton

Chronic Asthma Treatment

Zileuton is indicated for the prophylaxis and chronic treatment of asthma. It is used to help control symptoms and reduce the frequency of asthma attacks over time. The medication is intended for regular, daily use to maintain lung function in patients with persistent asthma.

Usage Considerations

When used as part of an asthma management plan, zileuton is typically prescribed to:

• Provide ongoing control of respiratory symptoms.
• Help prevent the onset of asthma attacks.
• Improve daily breathing capacity.

It is important to note that zileuton is not a rescue medication. It will not work fast enough to stop an asthma attack that has already started. Patients must continue to use a separate, fast-acting rescue inhaler for the immediate relief of sudden shortness of breath or wheezing. Zileuton must be taken consistently as directed, even during periods when no asthma symptoms are present, to remain effective.

Mechanism of Action

Zileuton is classified as a leukotriene synthesis inhibitor. It works by interfering with a specific enzyme in the body called 5-lipoxygenase. This enzyme is responsible for the production of leukotrienes, which are inflammatory chemicals released during an asthma response.

When the body produces leukotrienes, they cause several reactions in the lungs that make breathing difficult, including:

• Inflammation: Swelling of the airway lining.
• Bronchoconstriction: Tightening of the muscles surrounding the airways.
• Mucus production: Increased fluid in the respiratory tract.

By inhibiting the enzyme that creates these chemicals, zileuton helps prevent the swelling and tightening of the airways before they occur. This helps manage chronic asthma symptoms and improves overall lung function over time. Because it works by preventing the formation of these substances rather than reversing their effects immediately, it is used for long-term control rather than the immediate relief of an acute asthma attack.

Common Side Effects

Many people using zileuton experience mild side effects. These may include:

• Headache
• Stomach pain, nausea, or heartburn
• Diarrhea or gas
• Muscle aches or general pain
• Nervousness
• Runny nose or sore throat

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following serious symptoms:

Liver Problems

Zileuton can affect liver function. Watch for signs such as:

• Yellowing of the skin or eyes (jaundice)
• Dark-colored urine or pale stools
• Severe nausea or upper stomach pain
• Loss of appetite
• Unusual tiredness

Mood or Behavior Changes

Some patients experience mental health changes while taking this medication, including:

• Anxiety, agitation, or aggressive behavior
• Depression
• Sleep problems or unusual dreams
• Suicidal thoughts or actions

Allergic Reactions

Seek emergency medical help if you have signs of an allergic reaction, such as hives, difficulty breathing, or swelling of your face, lips, tongue, or throat.

Liver Function and Monitoring

Zileuton has been associated with elevations in liver enzymes, which may indicate liver injury. In rare cases, severe liver damage has occurred. Healthcare providers typically perform blood tests to check liver function before starting treatment and at regular intervals thereafter. Signs of liver problems may include pain in the upper right stomach area, nausea, fatigue, itching, or yellowing of the skin or eyes.

Contraindications

This medication must not be used by individuals who have active liver disease or those with persistent elevations in liver enzymes that are three times the upper limit of normal or higher.

Neuropsychiatric Events

Some people taking zileuton have reported changes in mood or behavior. These may include:

• Agitation or aggression
• Anxiety or depression
• Sleep disturbances or vivid dreams
• Suicidal thoughts or actions

Acute Asthma Attacks

Zileuton is a maintenance medication and will not stop an asthma attack that has already started. A fast-acting rescue inhaler should be used for sudden symptoms of shortness of breath or wheezing.

Drug Interactions

Zileuton can significantly increase the levels of certain other medications in the body, which may lead to toxicity. Notable interactions include theophylline, warfarin, and propranolol. Dose adjustments for these medications are often necessary when taken with zileuton.

Pregnancy

There are no adequate and well-controlled studies of zileuton use in pregnant women. In animal research, high doses of the medication were associated with adverse effects, including cleft palate and decreased fertility. Because animal studies are not always predictive of human response, zileuton should be used during pregnancy only if the potential benefit to the mother justifies the potential risk to the fetus.

If you are pregnant or planning to become pregnant, you should discuss the potential risks and benefits of this medication with your healthcare provider.

Breastfeeding

It is not known whether zileuton is excreted in human breast milk. Because many drugs are passed through breast milk and there is a potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue breastfeeding or discontinue the drug. This decision should consider the importance of the medication to the mother's health.

Consult with your doctor before breastfeeding while taking zileuton to determine the safest course of action for you and your child.

Available Forms

Zileuton is administered orally and is available in the following forms:

• Immediate-release tablets: This standard formulation is designed to release the medication into the system shortly after ingestion.
• Extended-release tablets: This formulation releases the medication gradually over time.

Both forms are intended for the chronic treatment of asthma and are not used to treat sudden asthma attacks.

FDA Approval Status

Zileuton was first approved by the U.S. Food and Drug Administration (FDA) in 1996. It is available in both immediate-release and extended-release formulations. The medication is indicated for the prophylaxis and chronic treatment of asthma; however, it is not indicated for use in the reversal of acute bronchospasm or as a rescue treatment for sudden asthma attacks.

Regulatory Classification

Zileuton is a prescription-only medication and is not a controlled substance. It belongs to the drug class known as leukotriene synthesis inhibitors.

Safety Requirements and Monitoring

The FDA-approved labeling for zileuton includes significant warnings regarding potential liver toxicity. While it does not carry a boxed warning, the regulatory status requires specific clinical monitoring. Healthcare providers are instructed to perform liver function tests (specifically serum alanine aminotransferase or ALT) before starting treatment and periodically during therapy. The medication is contraindicated in patients with active liver disease or those with persistent liver enzyme elevations at or above three times the upper limit of normal.

FDA-Approved Indications

Zileuton is approved by the U.S. Food and Drug Administration (FDA) for the long-term prevention and treatment of asthma. It is approved for use in adults and children 12 years of age and older. It is intended for daily management and is not approved for the treatment of sudden asthma attacks.

FDA Safety Warnings

The FDA requires specific safety precautions for patients using this medication, particularly regarding liver health and mental health:

• Liver Health: Because zileuton can cause liver damage, the FDA requires patients to have blood tests to check liver function before starting the drug and at regular intervals during treatment.
• Contraindications: This medication should not be used by people with active liver disease or those who have consistently high liver enzyme levels.
• Mental Health: The FDA-approved labeling includes warnings about potential mood or behavior changes, such as anxiety, irritability, sleep problems, or suicidal thoughts.

Usage Limitations

Zileuton is not a rescue medication. The FDA has not approved it for the relief of acute breathing problems or sudden bronchospasms. Patients are advised to always have a separate rescue inhaler available for emergency use.