Zileuton is used in aspirin-exacerbated respiratory disease (AERD). Its mechanism distinct from other anti-asthma drugs is:

• A Cysteinyl leukotriene receptor (CysLT1) antagonist, blocking LTD4 and LTE4
• B Phospholipase A2 inhibitor, preventing arachidonic acid release
• C COX-2 selective inhibitor, reducing prostaglandin-mediated bronchoconstriction
• D 5-lipoxygenase (5-LOX) inhibitor, preventing leukotriene synthesis (LTB4, LTC4, LTD4, LTE4) ✓

Explanation

Zileuton directly inhibits 5-lipoxygenase, the enzyme that converts arachidonic acid to 5-HPETE and subsequently to all leukotrienes including LTB4 (chemotaxis) and cysteinyl leukotrienes (LTC4/LTD4/LTE4, bronchoconstriction); this differs from montelukast and zafirlukast, which are CysLT1 receptor antagonists blocking only cysteinyl leukotriene effects. In AERD, aspirin shunts arachidonic acid toward the 5-LOX pathway, and zileuton prevents the resulting cysteinyl leukotriene overproduction.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.