Diphenoxylate/Atropine is an anti-diarrheal that primarily does what to GI motility?

• A. Stool softener
• B. Stimulant laxative
• C. Slows GI motility
• D. Antacid

Answer: (C)

The main idea is that this combination works by slowing the movement of the intestines. Diphenoxylate is an opioid receptor–agonist in the gut that reduces propulsive peristalsis, giving the intestines more time to absorb water from the stool and resulting in firmer stools and fewer bowel movements. Atropine is added in small amounts mainly to discourage misuse and add a mild anticholinergic effect, but it’s not the action that controls motility. This is not a stool softener, not a stimulant laxative (which would speed up transit), and not an antacid.