antidiarrheal

Antidiarrheals are medicines used to reduce the frequency and liquidity of stools. They provide symptomatic relief in acute nonspecific diarrhea and, in some cases, chronic diarrhea, but they do not treat the underlying cause. Options include opioid receptor–mediated agents that slow gut movement, antisecretory agents that reduce intestinal secretions, and, in some regions, other antisecretory or adsorptive preparations. Loperamide is the most widely used over-the-counter antidiarrheal in many countries. It acts on the enteric mu-opioid receptors to decrease peristalsis and increase transit time, producing firmer stools with little to no central nervous system effects due to limited absorption. Bismuth subsalicylate provides antisecretory effects and some antimicrobial activity; it can darken the tongue and stools and carries a risk of salicylate toxicity, so it is avoided in certain populations such as children with viral infections or those with aspirin allergy. Racecadotril is an antisecretory agent used in many regions; it reduces intestinal secretions without slowing motility, and is commonly used in pediatric diarrhea.

Safety and indications: These drugs are generally for short-term relief in non-infectious diarrhea and should not be used when there is suspected invasive bacterial infection, bloody diarrhea, high fever, or signs of dehydration without medical guidance. They should be used with caution in young children and in pregnant or breastfeeding people. Common adverse effects include constipation, abdominal cramps, and, with bismuth, tongue or stool discoloration.

Non-pharmacologic management, especially in children, includes oral rehydration therapy and, where appropriate, zinc supplementation. If diarrhea persists beyond 48 hours, or if there are red flags such as dehydration, high fever, or blood in stool, medical evaluation is needed.