Omeprazole
| Evidence Level: L3 | Predicted Indications: 10 |
Table of Contents
Omeprazole: From Acid-Related Gastric and Duodenal Disorders to Duodenogastric Reflux
One-Sentence Summary
Omeprazole is a proton pump inhibitor originally used for gastric and duodenal ulcers, gastroesophageal reflux disease (GERD), esophagitis and Zollinger-Ellison syndrome. The TxGNN model predicts it may be effective for duodenogastric reflux, but the supporting evidence is thin: 1 clinical trial (a diagnostic imaging study, not a treatment trial) and 15 publications, mostly small human studies, animal experiments and reviews. Animal data also raise a safety signal, so this is best treated as a research question rather than a ready candidate.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Gastric ulcer, peptic ulcer disease, GERD, esophagitis, duodenal ulcer, Zollinger-Ellison syndrome |
| Predicted New Indication | Duodenogastric reflux |
| TxGNN Prediction Score | 99.64% |
| Evidence Level | L3 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 20 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism-of-action data is not available in the data compiled for this report. Omeprazole belongs to the proton pump inhibitor class, which suppresses gastric acid. Its efficacy in acid-related diseases such as ulcers and reflux disease is well established.
Duodenogastric reflux is the backflow of bile and duodenal contents into the stomach. It is closely related to the approved reflux and ulcer indications and can damage the mucosa. Acid suppression may ease acid-related injury and symptoms. However, omeprazole does not stop bile or duodenal contents from refluxing, so any benefit would be indirect.
Small human studies in Barrett's oesophagus and a paediatric prospective study of oesophageal bile reflux suggest omeprazole may affect bile reflux measures. Animal studies point the other way: acid blockade combined with duodenogastric reflux promoted gastric mucosal growth and carcinogenesis in rats. This is a genuine safety question that must be resolved before any repurposing.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT02685150 | N/A | Completed | 157 | Endoscopic tri-modal imaging (narrow-band, autofluorescence and white-light) to tell reflux disease, including acid or bile reflux, from functional dyspepsia. This is a diagnostic study and does not test omeprazole efficacy. |
Literature Evidence
No randomised controlled trials were found for this indication.
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 10994616 | 2000 | Clinical study | Scand J Gastroenterol | Examined the effect of omeprazole on antral duodenogastric reflux in Barrett's oesophagus, building on reports that it may reduce reflux. |
| 9824338 | 1998 | Clinical study | Gut | Examined omeprazole 20 mg twice daily on duodenogastric and gastro-oesophageal bile reflux in Barrett's oesophagus. |
| 16641575 | 2006 | Prospective study | J Pediatr Gastroenterol Nutr | Studied the effect of proton pump inhibitor therapy on oesophageal bile reflux in children. |
| 12836018 | 2003 | Clinical study | Eur J Pediatr | Describes primary duodenogastric reflux in six children and adolescents with atypical reflux symptoms unresponsive to antacids. |
| 8076761 | 1994 | Clinical study | Gastroenterology | Studied how pH relates to duodenogastroesophageal reflux and oesophageal damage in Barrett's oesophagus. |
| 18679668 | 2008 | Review | Eur J Clin Pharmacol | Reviews clinical use and pharmacokinetics of PPIs, which are first choice for ulcer, reflux disease and Zollinger-Ellison syndrome. |
| 10389684 | 1999 | Animal study | Dig Dis Sci | In rats, acid blockade with omeprazole promoted gastric carcinogenesis induced by duodenogastric reflux (safety signal). |
| 8943968 | 1996 | Animal study | Dig Dis Sci | In rats, duodenogastric reflux stimulated foregut mucosal growth, potentiated by gastric acid blockade. |
| 33027361 | 2020 | Animal study | Acta Cir Bras | Investigated whether omeprazole protects against gastric adenocarcinoma in rats with induced duodenogastric reflux. |
Singapore Market Information
Omeprazole has 20 valid single-ingredient registrations in Singapore, covering oral capsules and tablets and lyophilised powder for injection. The table shows 5 of them.
| Authorization Number | Product Name | Dosage Form |
|---|---|---|
| SIN10700P | LOSEC MUPS Tablet 20 mg | Tablet, film coated |
| SIN14003P | Probitor Gastro-Resistant Capsule 20 mg | Capsule, delayed release |
| SIN13358P | Omezol Lyo-Injection | Injection, powder, lyophilised, for solution |
| SIN16330P | OMEPRO Powder for Solution for Injection 40 mg/vial | Injection, powder, lyophilised, for solution |
| SIN14019P | OMEPRADEX EC Tablet 20 mg | Tablet, enteric coated |
Safety Considerations
- Animal safety signal: In rats, omeprazole-induced acid blockade combined with duodenogastric reflux promoted gastric mucosal growth and carcinogenesis. Human relevance is unknown.
- Possible contraindication signals (from a knowledge graph, not label text): liver failure, liver disease, gallbladder disease, congestive heart failure, osteoporosis, postmenopausal osteoporosis, bone fracture and chronic atrophic gastritis.
- Drug interactions: 100 interactions were recorded. Major ones include acalabrutinib and atazanavir. Moderate ones include hydrochlorothiazide, alprazolam, amphotericin B (several formulations), amikacin, amphetamine, anagrelide, fenofibrate, apalutamide, armodafinil and atorvastatin. Minor ones include lidocaine, nifedipine, ambrisentan and acetylsalicylic acid.
Please refer to the package insert for official warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction score is high, but the only trial is a non-interventional diagnostic study. Human data are limited to small studies, mostly in Barrett's oesophagus or children. Omeprazole does not block bile reflux itself, and animal studies suggest acid blockade may worsen reflux-related mucosal injury. This is a research question, not a candidate ready for clinical development.
To proceed, the following is needed:
- Controlled human studies of omeprazole on bile or duodenogastric reflux outcomes, with clear endpoints such as bilimetry, symptoms and mucosal histology
- Safety evaluation of long-term acid suppression in patients with duodenogastric reflux, given the carcinogenesis signal in animals
- Detailed mechanism-of-action data and the Singapore package insert warnings and contraindications
- Assessment of the knowledge-graph contraindication signals (liver, bone, heart failure and atrophic gastritis) in the target population
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.