Explain the mechanism of action of omeprazole in the treatment of peptic ulcer disease and why it is preferred over H2‑receptor antagonists for long‑term ulcer healing.
Answer
Omeprazole irreversibly inhibits H⁺/K⁺ ATPase in gastric parietal cells, reducing acid secretion by 70–80 % and thereby allowing ulcer healing.
Step-by-step solution
- Step 1: Omeprazole is a prodrug that enters parietal cells via the H+/K+ ATPase proton pump.
- Step 2: Inside the acidic secretory canaliculi, omeprazole is protonated and covalently binds to cysteine residues of the H+/K+ ATPase.
- Step 3: This irreversible inhibition blocks the final step of gastric acid secretion, reducing acid output by 70–80 %.
- Step 4: The prolonged suppression of acid allows ulcer mucosa to heal and reduces recurrence, whereas H2 antagonists provide only transient acid reduction and are less effective for long‑term healing.
Common mistake: Assuming H2 antagonists are equally effective for ulcer healing
Concept tested: Proton‑pump inhibitor mechanism
Published · How this solution was prepared and checked
← All Human Health and Disease questions