Loperamide

Antidiarrheal (Opioid Agonist)

Drug Class: Antidiarrheal (Opioid Agonist)
Mechanism of Action (MOA): Peripheral µ-opioid agonist in the gut → ↓ peristalsis (no CNS penetration at normal doses).
Black Box Warning: Torsades de pointes, other serious ventricular arrhythmias, and sudden death with higher-than-recommended doses (including abuse/misuse).
Clinical Notes: Symptomatic non-infectious diarrhea. Avoid in bloody/febrile (invasive) diarrhea or C. diff. Cardiac arrhythmia with abuse/overdose.
Source: FDA label

Sources

Reviewed June 2026

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