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

The active ingredient in Zyflo is zileuton. Its mechanism of action is the inhibition of the 5-lipoxygenase (5-LO) enzyme. This enzyme is critical in the arachidonic acid pathway for the synthesis of leukotrienes, including LTB4, LTC4, LTD4, and LTE4. By inhibiting 5-LO, zileuton prevents the formation of these potent inflammatory mediators, which are responsible for bronchoconstriction, airway inflammation, and increased mucus production in asthma. This upstream inhibition distinguishes it from leukotriene receptor antagonists, which block the action of already-formed leukotrienes.

A. Ultra-long-acting beta-2 agonists (e.g., vilanterol) are bronchodilators that stimulate beta-2 adrenergic receptors, a different mechanism.
C. Leukotriene D4 inhibitors (e.g., montelukast) are receptor antagonists that block the CysLT1 receptor, not the synthesis of leukotrienes.
D. Long-acting anticholinergics (e.g., tiotropium) are bronchodilators that block muscarinic receptors in the airways.

1. U.S. Food and Drug Administration (FDA). (2012). ZYFLO CR (zileuton) extended-release tablets

for oral use. Full Prescribing Information. Section 12.1

Mechanism of Action. Retrieved from https://www.accessdata.fda.gov/drugsatfdadocs/label/2012/021830s009lbl.pdf

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Abstract. https://doi.org/10.1111/j.1742-1241.2007.01329.x

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Pharmacotherapy of Inflammation

Fever

Pain

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Section: "Inhibitors of Lipoxygenase."