Omeprazole
| Evidence Level: L3 | Predicted Indications: 10 |
Table of Contents
Omeprazole: From Acid Suppression (Proton Pump Inhibitor) to Duodenogastric Reflux
One-Sentence Summary
Omeprazole is a proton pump inhibitor (PPI), a class of drugs that lowers stomach acid. The TxGNN model predicts it may be effective for duodenogastric reflux (backflow of bile and duodenal contents into the stomach). This prediction is supported by 1 registered clinical trial, which does not test omeprazole, and 20 publications, mostly small clinical or animal studies with no clear evidence of benefit.
Quick Overview
| Item | Content |
|---|---|
| Predicted New Indication | Duodenogastric reflux |
| TxGNN Prediction Score | 99.64% |
| Evidence Level | L3 |
| South Africa Market Status | Marketed |
| Number of SAHPRA Registrations | 3 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the evidence pack. Based on known information, omeprazole is a proton pump inhibitor that suppresses gastric acid, and its efficacy in acid-related upper gastrointestinal disease is well established. Mechanistically, it could be relevant to reflux conditions.
The link is weak, however. Omeprazole suppresses acid but does not reduce the reflux of bile or duodenal content. Two small clinical studies (PMIDs 10994616 and 9824338) looked at its effect on duodenogastric reflux in Barrett’s oesophagus, and the results are not clearly beneficial. Two rat studies (PMIDs 33027361 and 10389684) suggest that acid suppression during duodenogastric reflux may promote gastric carcinogenesis, which is a safety signal.
The very high TxGNN score is a computational prediction and is not backed by clinical efficacy evidence.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT02685150 | Not applicable | Completed | 157 | Endoscopic tri-modal imaging to distinguish functional dyspepsia from reflux disease. It is an imaging study and does not test omeprazole. |
No SANCTR or PACTR entries were found in the evidence pack.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 10994616 | 2000 | Clinical study | Scand J Gastroenterol | Examined omeprazole’s effect on antral duodenogastric reflux in Barrett’s oesophagus. |
| 9824338 | 1998 | Clinical study | Gut | Effect of omeprazole 20 mg twice daily on duodenogastric and gastro-oesophageal bile reflux in Barrett’s oesophagus. |
| 16641575 | 2006 | Prospective study | J Pediatr Gastroenterol Nutr | Effect of omeprazole on oesophageal bile reflux in children. |
| 11232672 | 2001 | Clinical study | Am J Gastroenterol | Compared acid and bile reflux in Barrett’s oesophagus versus reflux oesophagitis, and tested PPI therapy. |
| 9841990 | 1998 | Clinical study | J Gastrointest Surg | Bile reflux in benign and malignant Barrett’s oesophagus, with acid suppression and Nissen fundoplication. |
| 19491829 | 2009 | Clinical study | Am J Gastroenterol | Compared duodenogastro-oesophageal and acid reflux in PPI responders and non-responders. |
| 12836018 | 2003 | Cohort | Eur J Pediatr | Six children with primary duodenogastric reflux and atypical symptoms unresponsive to antacid therapy. |
| 10389684 | 1999 | Animal study | Dig Dis Sci | In rats, omeprazole acid blockade promoted gastric carcinogenesis induced by duodenogastric reflux (safety signal). |
| 33027361 | 2020 | Animal study | Acta Cir Bras | Tested whether omeprazole protects against stomach adenocarcinoma in rats with induced duodenogastric reflux. |
| 12970129 | 2003 | Clinical study | Gut | Baclofen for patients with duodenal reflux symptoms that persist on PPI therapy. |
The evidence pack contains no randomised controlled trial for this indication.
South Africa Market Information
| Registration Number | Product Name | Dosage Form |
|---|---|---|
| Reg. No. A39/11.4.3/0466 | Rapacid | Capsule |
| Reg. No. 34/11.4.3/0301 | Omez | Capsule |
| Reg. No. 43/11.4.3/0502 | Corpocid | Tablet |
All three products are oral. Approved indication text and Essential Medicines List status were not available in the evidence pack.
Safety Considerations
Please refer to the SAHPRA-approved Professional Information (PI) for safety information. Report adverse drug reactions to SAHPRA.
Two rat studies (PMIDs 10389684 and 33027361) suggest acid suppression may promote gastric carcinogenesis in the setting of duodenogastric reflux. This is animal data only and needs clinical clarification.
Conclusion and Next Steps
Decision: Hold
Rationale: Omeprazole does not reduce bile or duodenal reflux, and the small human studies show no clear benefit. Rat studies raise a carcinogenesis concern, and the only registered trial does not test omeprazole. The high TxGNN score is not supported by clinical evidence.
To proceed, the following is needed:
- SAHPRA package insert warnings and contraindications (a blocking gap for safety screening)
- Mechanism of action data from DrugBank
- The approved indication text for the three registered products
- Controlled clinical evidence of benefit in duodenogastric reflux, and clarification of the rat-study carcinogenesis signal
Note on other predictions: The evidence pack also lists an “active peptic ulcer disease” prediction with stronger evidence (L1, Proceed with Guardrails). Omeprazole is very likely already labelled for peptic ulcer, so it may not be true repurposing. Verify the local label before treating it as a new indication.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.