Medicine & USMLE

Bismuth Subsalicylate

GI Drugs
  1. Ondansetron
  2. Sucralfate
  3. Docusate (Stool Softener)
  4. Bulk Forming Laxatives (Psyllium, Methylcellulose)
  5. Osmotic Laxatives (Lactulose, PEG)
  6. Stimulant Laxatives (Senna, Bisacodyl)
  7. Antidiarrheals (Loperamide, Diphenoxylate-Atropine)
  8. Bismuth Subsalicylate
  9. Antacids
  10. Proton Pump Inhibitors (PPIs)
  11. H2 Blockers
  12. Metoclopramide
  13. Misoprostol
  14. Orlistat
  15. Octreotide


Bismuth subsalicylate, commonly known as Pepto Bismol, is used to treat diarrhea, GERD, and nausea. It can cause Reye syndrome, a rare form of acute liver failure and encephalopathy in children, so it should not be given to children. A benign but expected side effect of bismuth subsalicylate is dark or black-colored stools.

Key Points

  • Bismuth Subsalicylate
    • Mechanism
      • Antidiarrheal
      • Antacid
      • Antiemetic
      • Prevents bacterial binding to the mucosal cells in the GI tract, promoting fluid absorption and reducing inflammation
    • Clinical Use
      • Diarrhea
        • Including traveler’s diarrhea
      • Gastroesophageal Reflux Disease (GERD)
      • Nausea
      • H. Pylori infection
        • Used in combination with an antibiotic and proton pump inhibitor
    • Side Effects and Adverse Reactions
      • Reye Syndrome (in children)
        • Acute liver failure and encephalopathy when given to children
        • Should not be given to children as it contains an aspirin-like compound
      • Dark stools
        • An expected side effect; not a reason to discontinue the medication
      • Tinnitus
        • Similar to aspirin, this is a sign of toxicity
      • Drowsiness
      • Headache