Which statement is true regarding the relative acid-suppressing ability of proton pump inhibitors compared with histamine-2 receptor antagonists?

Which statement is true regarding the relative acid-suppressing ability of proton pump inhibitors compared with histamine-2 receptor antagonists?

• A. PPIs suppress significantly more acid than H2-blockers
• B. H2-blockers suppress more acid than PPIs
• C. They have equal acid suppression
• D. They increase acid secretion

Answer: (A)

Proton pump inhibitors provide more potent acid suppression because they shut down the final common pathway of acid secretion. They irreversibly inhibit the H+/K+-ATPase (the proton pump) in gastric parietal cells, so once these pumps are blocked, acid output drops dramatically and remains suppressed until new pumps are made. In contrast, histamine-2 receptor antagonists only block the action of histamine on H2 receptors, reducing acid secretion driven by this one stimulant and allowing other stimulants (gastrin and acetylcholine) to continue promoting acid production. They are less powerful overall and can lose effectiveness over time (tachyphylaxis) with chronic use. So, the PPIs suppress significantly more acid than H2-blockers, with a slower onset but more sustained and greater overall suppression.

Proton pump inhibitors provide more potent acid suppression because they shut down the final common pathway of acid secretion. They irreversibly inhibit the H+/K+-ATPase (the proton pump) in gastric parietal cells, so once these pumps are blocked, acid output drops dramatically and remains suppressed until new pumps are made. In contrast, histamine-2 receptor antagonists only block the action of histamine on H2 receptors, reducing acid secretion driven by this one stimulant and allowing other stimulants (gastrin and acetylcholine) to continue promoting acid production. They are less powerful overall and can lose effectiveness over time (tachyphylaxis) with chronic use. So, the PPIs suppress significantly more acid than H2-blockers, with a slower onset but more sustained and greater overall suppression.