Which term stops diarrhea?

• A. Antiflatulent
• B. Antidiarrheal
• C. Antacid
• D. Antiemetic

Answer: (B)

This question tests recognizing drug classes by their intended therapeutic effect: stopping diarrhea is the job of antidiarrheals. Antidiarrheals work by reducing the frequency and liquidity of stools, either by slowing intestinal motility (for example, opioid-like agents) or by reducing secretions and supporting water absorption (such as certain adsorbents or antisecretory compounds). Examples include loperamide, diphenoxylate, and bismuth subsalicylate, which help firm up stool and decrease stool volume.

The other terms describe different goals: antiflatulent relieves gas and bloating, not diarrhea; antacid neutralizes stomach acid, addressing heartburn rather than bowel movements; and antiemetic prevents nausea and vomiting, not diarrhea.