What is the mechanism of action of the active ingredient found in Zyflo?

Zileuton is the active ingredient found in the medicine Zyflo; a medicine that works as a 5-lipoxygenase inhibitor. As such, zileuton inhibits leukotrienes (LTB4, LTC4, LTD4, and LTE4) formation, and is used for the maintenance treatment of asthma in patients older than the age of 12. In 2 percent of patients, it raises liver enzymes. Sinusitis and nausea are the most common side effects.