Neomycin
| Evidence Level: L2 | Predicted Indications: 10 |
Table of Contents
Neomycin: From Antibacterial Use to Irritable Bowel Syndrome
One-Sentence Summary
Neomycin is an aminoglycoside antibiotic marketed in South Africa in topical, ophthalmic and other forms. The TxGNN model predicts it may be useful for Irritable Bowel Syndrome (IBS), particularly constipation-predominant IBS in patients who test positive for methane. This direction is supported by 2 clinical trials and 14 publications, but the trials are small and the key safety data are still missing.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not stated in the registration data provided (drug class: aminoglycoside antibiotic) |
| Predicted New Indication | Irritable bowel syndrome |
| TxGNN Prediction Score | 98.55% |
| Evidence Level | L2 |
| South Africa Market Status | Marketed |
| Number of SAHPRA Registrations | 12 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the input. Based on the literature, oral neomycin is poorly absorbed and acts locally in the gut. It may reduce small intestinal bacterial overgrowth (SIBO) and methane-producing gut flora.
Methane production is linked to constipation-predominant IBS (C-IBS). Published analyses suggest that neomycin’s benefit in C-IBS depends on methane status. It appears to help mainly patients with methane on breath testing. Combining neomycin with rifaximin looked more effective than either drug alone in methane-positive patients.
This link rests on the literature, not on a confirmed mechanism in the input data. Much of the supporting evidence concerns rifaximin, and the neomycin-specific studies are small.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT00945334 | NA | Completed | 37 | Double-blind, placebo-controlled trial of neomycin vs rifaximin plus neomycin in methane-positive C-IBS. Directly on-drug and on-indication, but small. No results summary in the data provided. |
| NCT00259155 | Phase 2 | Completed | 92 | Randomized double-blind trial of rifaximin in SIBO and IBS. Neomycin is not the test drug, so this supports the antibiotic and dysbiosis rationale only indirectly. |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 19996983 | 2010 | RCT | J Clin Gastroenterol | Compared three antibiotic regimens in IBS patients with methane-positive breath tests. The rifaximin plus neomycin combination was most effective. |
| 16832617 | 2006 | RCT (subanalysis) | Dig Dis Sci | In C-IBS, neomycin improved constipation in a way that depended on the presence of methane. |
| 12591062 | 2003 | RCT (per title) | Am J Gastroenterol | Double-blind, placebo-controlled study. Normalisation of the lactulose breath test after antibiotic treatment correlated with symptom improvement. |
| 24788320 | 2014 | Review | Dig Dis Sci | Antibiotic treatment of C-IBS. Methane production is linked to constipation severity. A prior retrospective study suggested rifaximin plus neomycin beat neomycin alone. |
| 40240267 | 2025 | Prospective comparative study | Rev Gastroenterol Mex | Compared three antibiotic regimens for SIBO in Chilean IBS patients (symptom response and SIBO eradication). |
| 22298980 | 2011 | Not classified | Gastroenterol Hepatol | Overview of antibiotics for IBS, covering post-infectious IBS and SIBO. |
| 30288076 | 2018 | Review | Clin Exp Gastroenterol | Rifaximin in IBS-D: mechanism, gut microbiota effects, safety and tolerability. |
| 24666019 | 2014 | Review | Curr Med Res Opin | Role of probiotics and antimicrobials in managing functional bowel disorders, including IBS. |
| 38700306 | 2023 | Review | J Assoc Physicians India | Gut dysbiosis in IBS, including antibiotics and SIBO as contributing factors. |
| 31363445 | 2019 | Not classified | Cureus | Methane production and dysbiosis in C-IBS. |
South Africa Market Information
Approved indication text was not provided for any of these registrations. No Essential Medicines List (EML) status data is available.
| Registration Number | Product Name | Dosage Form |
|---|---|---|
| G1831 | Betnovate ‘n’ | Ointment |
| G2023 (OM) | Neoderm | Cream |
| H1236 (OM) | Covomycin 7.5ml | Not clearly specified in the data |
| H.1158 | Maxitrol 3.5g | Eye ointment |
| D/2.5/204 | Tegretol s | Suspension |
The trials in IBS used oral neomycin. The five products above are topical, ophthalmic or unclear forms. An oral tablet is listed among the 12 registrations, but which product it is was not provided. “Tegretol s” is normally a carbamazepine product, so this entry may be a data-mapping error and should be checked against SAHPRA records.
Safety Considerations
- Drug Interactions: The interaction query returned no records.
- Contact allergy: The retrieved literature repeatedly identifies neomycin as a frequent contact allergen, including in systematic and cohort studies of dermatitis patients. This is most relevant to topical use.
Please refer to the SAHPRA-approved Professional Information (PI) for warnings and contraindications. Report adverse drug reactions to SAHPRA.
Conclusion and Next Steps
Decision: Hold
Rationale: IBS is the only predicted indication with meaningful clinical support. That support comes from small trials (n=37 and n=92, one of which tested rifaximin rather than neomycin) and methane-dependent subgroup findings. The missing SAHPRA safety information is a blocking gap, so the candidate cannot yet move past safety screening.
The other nine predicted indications are much weaker and stay on Hold. Peripheral arterial disease, acute laryngopharyngitis and ischaemic disease have prediction-only evidence. For dermatitis, the literature shows neomycin mainly as a cause of allergic contact dermatitis.
To proceed, the following is needed:
- SAHPRA package insert warnings and contraindications for neomycin products
- Confirmation of which oral neomycin product, if any, is registered in South Africa
- Mechanism of action data (MOA)
- A larger, adequately powered controlled trial in methane-positive C-IBS
- An antimicrobial stewardship and resistance assessment for repeated antibiotic courses in a chronic functional condition
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.