Can omeprazole (proton pump inhibitor) cause gastritis?

Can Omeprazole Cause Gastritis?

Omeprazole does not typically cause gastritis; however, long-term use may lead to changes in gastric mucosa including increased corpus gastritis in patients with Helicobacter pylori infection. 1

Mechanism and Evidence

Proton pump inhibitors (PPIs) like omeprazole are actually prescribed to treat and prevent conditions involving gastric acid, including gastritis. They work by blocking gastric acid secretion and have additional anti-inflammatory properties that can help heal gastric inflammation 2.

However, the relationship between omeprazole and gastritis is complex:

1. H. pylori-related effects:

   • In H. pylori-positive patients, long-term omeprazole therapy can alter the distribution of H. pylori in the stomach
   • Studies show that during PPI therapy, H. pylori colonization and inflammation may shift from the antrum to the corpus of the stomach 1
   • This redistribution can lead to increased corpus gastritis despite decreased antral inflammation 1

2. Acid suppression consequences:

   • Profound acid suppression from omeprazole can lead to bacterial overgrowth in the stomach 3
   • In some patients, this may contribute to changes in gastric mucosa

3. Long-term effects:

   • Extended omeprazole use (months to years) has been associated with:
     • Endocrine cell hyperplasia in 27.8% of patients 4
     • Progression of chronic gastritis in some patients 4
     • Increased incidence of chronic atrophic gastritis (from 1.0% to 13.0% in patients treated for at least 330 days) 4

Clinical Implications

The European position paper on rhinosinusitis and nasal polyps (2020) notes that "long-term use of proton pump inhibitors is not without risk" 5. Similarly, a 2022 study suggested that continuous and prolonged omeprazole use may induce genetic instability in gastric cells, particularly in patients with H. pylori infection 6.

However, it's important to note that:

1. The American Gastroenterological Association still recommends PPI therapy as first-line treatment for conditions like GERD 2
2. For patients with H. pylori infection on long-term PPI therapy, eradication of H. pylori is recommended to prevent progression of gastritis 7
3. The FDA label for omeprazole does not list gastritis as a common adverse effect, though it does mention gastrointestinal effects like irritable colon, anorexia, and abdominal swelling 8

Management Considerations

For patients requiring long-term acid suppression:

• Consider H. pylori testing before initiating long-term PPI therapy
• In H. pylori-positive patients who need long-term PPI therapy, eradication of H. pylori is recommended 7
• Use the lowest effective dose of PPI that controls symptoms 2
• Consider periodic monitoring for gastric mucosal changes in patients on long-term therapy
• Be aware that testing for H. pylori in patients on profound acid suppressive therapy should include both corpus and antral specimens 1

Conclusion

While omeprazole itself is not a primary cause of gastritis, long-term use may lead to changes in gastric mucosa, particularly in H. pylori-positive individuals. The benefits of PPI therapy in appropriate patients typically outweigh these risks, but awareness of potential mucosal changes is important for those requiring extended treatment.