Loperamide is primarily used to achieve which therapeutic effect?

• A. Increase intestinal transit
• B. Slow intestinal transit
• C. Decrease gastric acid
• D. Promote bile acid secretion

Answer: (B)

Slowing intestinal transit is the therapeutic effect of loperamide. It binds to mu-opioid receptors in the enteric nervous system, which reduces propulsive gut movements and prolongs the time content spends in the intestines. That extra time allows more water and electrolytes to be reabsorbed, producing firmer stools and fewer diarrheal episodes. Loperamide acts mainly in the gut and has minimal CNS effects, which is why it’s used for diarrhea management rather than pain relief or systemic actions.

It does not decrease gastric acid secretion, nor does it promote bile acid secretion, and it does not increase intestinal transit. These distinctions explain why slowing transit is the correct mechanism for loperamide’s therapeutic effect.