This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which of the following is a lipoxygenase inhibitor: March 2012 
Select and explain. 
A. Montelukast, B. Thromboxanes, C. Zileuton, D. Sodium cromoglycate
C: Zileuton
Answer: C: Zileuton 
Explanation: Ans: C i.e. Zileuton Drugs and mechanism of action Montelukast competitively antagonize cysLT1 receptor mediated bronchoconstriction, increased vascular permeability and recruitment of eosinophils. Thromboxane acts by binding to any of the thromboxane receptors, G protein coupled receptors coupled to G-protein Gq. Zileuton is a 5 lipo-oxygenase inhibitor, blocks LT C4/ D4 as well as LTB4 synthesis. Sodium cromoglycate inhibits degranulation of mast cells. The basis of this effect is not well understood, but may involve a delayed chloride channel in the membrane of these cells.