Which option is NOT a mechanism of GI acid suppression?

• A. Neutralizes acid
• B. Inhibits proton pumps
• C. Blocks histamine receptors
• D. Act as antibiotics

Answer: (D)

GI acid suppression can work by buffering acid, or by reducing acid production at the stomach lining. Neutralizing acid with antacids provides quick, temporary relief by raising pH, but it doesn’t give lasting suppression of acid production. Inhibiting proton pumps blocks the final step of acid secretion in parietal cells, leading to a strong and sustained decrease in acid output. Blocking histamine receptors also reduces acid-secreting signals, lowering production over time. Antibiotics don’t directly suppress gastric acid; they target bacteria such as H. pylori and are used for infection treatment rather than acid suppression, so they aren’t a mechanism for reducing acid.