Misoprostol is prescribed to a patient receiving long-term NSAID therapy. Its gastric cytoprotective action is explained by:

• A Irreversible inhibition of parietal cell H+/K+-ATPase
• B Agonist action at prostaglandin EP2 and EP3 receptors, increasing mucus and bicarbonate secretion ✓
• C Formation of an insoluble complex over the ulcer crater
• D Selective antagonism of histamine H2 receptors on parietal cells

Explanation

Misoprostol is a synthetic PGE1 analogue that mimics endogenous prostaglandin-mediated mucosal defence: it stimulates mucus and bicarbonate secretion, maintains mucosal blood flow, and modestly inhibits acid secretion via EP2 and EP3 receptors. It replaces the prostaglandin synthesis suppressed by NSAIDs. Sucralfate forms the protective complex (option C), while PPIs and H2 blockers act purely on acid suppression without restoring mucosal defence.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.