Which of the following is an example of a proton pump inhibitor?

• A. Omeprazole
• B. Ranitidine
• C. Sucralfate
• D. Acetaminophen

Answer: (A)

Omeprazole is an example of a proton pump inhibitor. Proton pump inhibitors block the final step of gastric acid production by inhibiting the H+/K+-ATPase enzyme (the proton pump) on the parietal cell membranes. This irreversibly disables the pump, leading to a sustained reduction in acid secretion. Omeprazole is a prodrug that becomes activated in the acidic environment of the parietal cells and then covalently binds to the pump, producing long-lasting acid suppression that helps manage conditions like GERD and peptic ulcers. This strong, enduring effect distinguishes PPIs from other acid-reducing options. Ranitidine works by blocking histamine H2 receptors, sucralfate coats ulcers without reducing acid, and acetaminophen is an analgesic with no impact on gastric acid.