Which mechanism of action is shared by Loperamide (Imodium), Diphenoxylate (Lomotil), and Eluxadoline (Viberzi)?

Loperamide, diphenoxylate, and eluxadoline all exhibit their primary therapeutic effects through interaction with the mu-opioid receptors in the gastrointestinal tract. By activating these receptors, they effectively reduce gastrointestinal motility, leading to a decrease in the frequency and urgency of bowel movements. This mechanism makes them particularly useful in the management of diarrhea.

Loperamide is primarily used for symptomatic relief in cases of acute and chronic diarrhea, while diphenoxylate is combined with atropine to deter misuse and enhance its antidiarrheal effects. Eluxadoline serves a similar purpose but specifically targets the mu-opioid receptor alongside other receptors, providing a multifaceted approach to treating irritable bowel syndrome with diarrhea.

The shared action of mu-opioid agonism among these medications is key to their effectiveness in reducing bowel activity and helping manage diarrhea, distinguishing them clearly from other opioid receptors like kappa or delta, which have different pathways and effects in the body.