Zileuton

Zileuton

Zileuton is a medication used in the management and treatment of asthma. Classified as a leukotriene inhibitor, it works by blocking the action of substances in the body called leukotrienes, which are involved in the inflammatory process that contributes to asthma symptoms. Zileuton is specifically indicated for the prevention and chronic treatment of asthma in adults and children 12 years of age and older.

Mechanism of Action

Zileuton operates by inhibiting 5-lipoxygenase, an enzyme that catalyzes the formation of leukotrienes from arachidonic acid. Leukotrienes are potent eicosanoids that contribute to inflammation, bronchoconstriction, mucus production, and airway edema, all of which are symptomatic of asthma. By blocking the synthesis of leukotrienes, zileuton reduces inflammation, decreases mucus secretion, and prevents airway constriction, thereby aiding in the management of asthma symptoms.

Pharmacokinetics

After oral administration, zileuton is rapidly absorbed, with peak plasma concentrations occurring within 1 to 2 hours. It is extensively metabolized in the liver, primarily through the cytochrome P450 system, and has a half-life of approximately 2.5 to 5.5 hours. The drug is excreted mainly in the urine as metabolites.

Indications

Zileuton is indicated for the prophylaxis and chronic treatment of asthma in adults and children 12 years of age and older. It is not intended for the relief of acute asthma attacks.

Contraindications

Zileuton is contraindicated in patients with active liver disease or persistent elevations of serum transaminases (ALT or AST) above three times the upper limit of normal. Caution is advised when using this medication in patients with a history of liver disease.

Adverse Effects

Common adverse effects of zileuton include dyspepsia, nausea, and headache. Liver enzyme abnormalities may occur, and regular monitoring of liver function tests is recommended during treatment. Less common but more serious side effects include liver injury, and patients should be advised to report any symptoms of potential liver dysfunction such as jaundice, dark urine, or persistent nausea.

Drug Interactions

Zileuton is metabolized by the cytochrome P450 system and can interact with other drugs metabolized by this pathway. It may increase plasma concentrations of drugs such as warfarin and theophylline, necessitating monitoring and potential dose adjustments of these medications.

Dosage and Administration

The recommended dosage of zileuton is 600 mg four times daily, taken with or without food. Dose adjustments may be necessary for patients with liver impairment or those experiencing adverse effects.

Conclusion

Zileuton is an effective medication for the prevention and chronic treatment of asthma in adults and children over the age of 12. Its ability to inhibit leukotriene synthesis offers a targeted approach to reducing inflammation and managing asthma symptoms. However, monitoring for liver enzyme abnormalities is crucial during treatment with zileuton due to the potential for liver injury.