antidiarrheal /-dī′ərē″əl/ , a drug or dietary fiber–forming agent that relieves the symptoms of diarrhea. The most effective antidiarrheal drugs are opioid derivatives, which slow intestinal motility to permit greater time for the absorption of water and electrolytes. Dietary fiber–forming agents improve stool consistency but may not decrease fluid and electrolyte loss. Infectious diarrhea (for example, traveler’s diarrhea) may require antibiotics if severe.
