Which of the following drugs is a proton pump inhibitor (PPI) used for the treatment

Which of the following drugs is a proton pump inhibitor (PPI) used for the treatment

Which of the following drugs is a proton pump inhibitor (PPI) used for the treatment of gastroesophageal reflux disease (GERD) and peptic ulcer disease?

A. Ranitidine

B. Omeprazole

C. Famotidine

D. Cimetidine

Answer: B

Explanation: Omeprazole is a classic PPI that irreversibly inhibits H+/K+-ATPase in gastric parietal cells, reducing gastric acid secretion. Ranitidine, famotidine, and cimetidine are histamine H2-receptor antagonists (H2 blockers), which block acid secretion via a different mechanism (A, C, D are incorrect).