Question

Which of the following is a proton pump inhibitor?

• A. Ranitidine
• B. Misoprostol
• C. Omeprazole
• D. Lafutidine

Hint:

Look for the drug whose name ends in -prazole.

Answer 1

The Correct Option is C

Stomach acid is made by parietal cells using an enzyme called the proton pump, formally the $H^{+}/K^{+}$ ATPase. Drugs that bind this enzyme and switch it off are called proton pump inhibitors, and they are the most powerful acid suppressors we have. The easy clue is the name ending in -prazole.

Among the options, omeprazole is the original member of this group and fits the -prazole pattern perfectly, so it is the proton pump inhibitor. The other three act elsewhere: ranitidine and lafutidine both block the histamine $H_2$ receptor on the parietal cell, reducing acid by a different and weaker route, while misoprostol is a prostaglandin analogue that boosts mucosal protection rather than blocking the pump. Only omeprazole targets the pump itself.
\[\boxed{\text{Omeprazole}}\]