Proton Pump Inhibitors

Key points

• PPIs (omeprazole, lansoprazole): irreversibly block the H⁺/K⁺ ATPase (proton pump) of the gastric parietal cell.
• Can reduce gastric acid secretion by up to 99%; acid production resumes with renewal of parietal cells.
• Interactions: may reduce clopidogrel efficacy (omeprazole/esomeprazole via CYP2C19) — lansoprazole preferred if needed.
• Long-term use associations: hypomagnesaemia, B12 deficiency, increased fracture and C. difficile risk.

Decision points in this pathway

• Patient on clopidogrel?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.