Medicine & USMLE

Proton Pump Inhibitors (PPIs)

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


Proton pump inhibitors, or PPIs, are a class of drugs easily recognizable by their “-prazole” endings, including omeprazole, lansoprazole, and pantoprazole. PPIs work to suppress production of stomach acid, which can be used to treat and prevent stomach ulcers and acid reflux, also known as GERD. There aren’t many short-term side effects of these drugs, but if taken for a long period of time, PPIs can increase the risk of developing osteoporosis and bone fractures, infections with c. difficile, and pneumonia.

Key Points

  • Proton Pump Inhibitors (PPI)
    • Key Drugs
      • “-prazole”
        • Omeprazole (Prilosec)
        • Lansoprazole (Prevacid)
        • Pantoprazole (Protonix)
        • Esomeprazole (Nexium)
    • Mechanism
      • Suppress gastric acid (proton) secretion
        • Binds to the hydrogen/potassium ATPase enzyme system in the gastric parietal cells, stopping the production of gastric acid
        • Most effective when taken first thing in the morning on an empty stomach
    • Clinical Use
      • Prevent ulcers (treatment and prophylaxis)
        • Peptic Ulcers
        • Drug-induced ulcers (e.g. NSAIDs, aspirin)
        • H. pylori infection
          • Given in combination with an antibiotic
        • Stress ulcers
          • Often given post-surgery prophylactically to prevent ulcers brought on by surgical stress
      • Gastroesophageal Reflux Disease (GERD)
      • Esophagitis
    • Side Effects and Adverse Reactions
      • Short-term
        • Headache
        • Diarrhea
        • Nausea and vomiting
      • Long-term
        • Osteoporosis
          • Calcium is more soluble in acidic environments; reducing stomach acid causes precipitation and less absorption of calcium in the gut
          • Encourage to increase calcium and vitamin D intake
        • C. difficile infection
          • Stomach acid helps kill bacteria like c. difficile, so a reduction in stomach acid may allow bacteria to grow
        • Pneumonia
          • Thought to be due to protective effect of gastric acid against aspiration of ingested bacteria
        • Vitamin B12 deficiency
          • PPIs decrease gastric acids that are necessary for absorption
        • Rebound acid hypersecretion
        • Hypomagnesemia