Adverse effects

• Gastrointestinal
  • ↑ Risk of C. difficile infection
  • ↓ Absorption of iron and vitamin B12
  • ↓ Absorption of calcium and magnesium → ↑ risk of osteoporosis in long-term use→ ↑ risk of fractures in elderly individuals
    • Because the gastric environment becomes less acidic, dietary calcium remains bound to oxalate, resulting in reduced absorption in the duodenum and jejunum.
  • The resultant increase in gastric pH leads to increased gastrin formation, which, over time, can lead to hypertrophy of ECL and parietal cells. After chronic use (eg, >8 weeks), abrupt cessation of the PPI can trigger rebound gastric acid hypersecretion by the hyperfunctioning parietal cells, leading to reflux symptoms; PPIs can be slowly tapered to prevent this adverse effect.