Montelukast is used as add-on therapy in asthma. It is a cysteinyl leukotriene type-1 (CysLT1) receptor antagonist. Which pathophysiological effects of leukotrienes does it block?
- A Neutrophil chemotaxis (LTB4-mediated), bronchoconstriction, and mast cell degranulation
- B Bronchoconstriction (LTD4 most potent), mucus hypersecretion, airway eosinophil recruitment, and airway wall edema ✓
- C Bronchoconstriction and IgE production from B cells
- D Mast cell tryptase release causing collagen deposition and subepithelial fibrosis
Correct answer: B. Bronchoconstriction (LTD4 most potent), mucus hypersecretion, airway eosinophil recruitment, and airway wall edema
Explanation
CysLT1 receptors mediate the effects of LTC4, LTD4, and LTE4 — montelukast blocks these effects including: bronchoconstriction (LTD4 is 1000× more potent than histamine), increased mucus secretion, airway eosinophil influx, airway wall vascular permeability and edema. LTB4, the chemotactic leukotriene acting on neutrophils, signals through BLT1/BLT2 receptors and is NOT blocked by montelukast. Montelukast is particularly effective for exercise-induced and aspirin-sensitive asthma.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.