From the FDA Drug Label
Omeprazole delayed-release capsules can cause serious side effects, including: • Diarrhea. Omeprazole delayed-release capsules may increase your risk of getting severe diarrhea. This diarrhea may be caused by an infection (Clostridium difficile) in your intestines.
Yes, omeprazole can cause diarrhea, including severe diarrhea that may be caused by an infection (Clostridium difficile) in the intestines 1.
From the Research
Yes, omeprazole can cause diarrhea as a side effect, as evidenced by a case report where a patient developed severe diarrhea after taking omeprazole, likely due to the accumulation of omeprazole metabolites resulting from its slow metabolism in vivo 2.
Omeprazole and Diarrhea
Omeprazole is a proton pump inhibitor (PPI) that reduces gastric acid secretion, and while most people tolerate it well, gastrointestinal disturbances including diarrhea, abdominal pain, and nausea are among the more common adverse effects.
- The mechanism behind PPI-induced diarrhea may involve alterations in gut microbiota, as stomach acid normally helps regulate bacterial populations in the digestive tract.
- When acid production is suppressed by omeprazole, changes in bacterial composition can occur, potentially leading to diarrhea.
- Additionally, reduced acid may affect digestive enzyme activity and nutrient absorption.
Management of Omeprazole-Induced Diarrhea
If you experience persistent or severe diarrhea while taking omeprazole, you should consult your healthcare provider, as they may recommend:
- Reducing the dose
- Switching to a different PPI
- Trying an alternative acid-reducing medication such as an H2 blocker (like famotidine) Never stop taking prescribed omeprazole suddenly without medical guidance.
Evidence from Studies
A study published in 2017 found that omeprazole treatment caused significant changes in stool culture results, with patients treated with a higher dose of omeprazole having a tendency towards decreased diversity of colonic microflora 3. Another study published in 1998 reported that diarrhea was one of the most commonly reported adverse events in patients taking omeprazole, along with headache, dizziness, flatulence, abdominal pain, and constipation 4.