A 32-year-old man with persistent mild asthma is prescribed a daily oral leukotriene modifier. Which receptor does this class of drug block?

• A Histamine H1 receptor
• B Beta-2 adrenergic receptor
• C Cysteinyl leukotriene-1 receptor ✓
• D Leukotriene B4 receptor

Explanation

Montelukast and zafirlukast are antagonists at the cysteinyl leukotriene-1 receptor, blocking the bronchoconstrictor and mucosal edema effects of LTC4, LTD4 and LTE4. Zileuton, by contrast, is not a receptor antagonist but an inhibitor of 5-lipoxygenase, the enzyme that makes leukotrienes from arachidonic acid. LTB4 acts mainly on neutrophils through BLT receptors and is not the target of antiasthma therapy. These drugs are additive controllers, not relievers.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.