Nalidixic Acid
| Evidence Level: L4 | Predicted Indications: 4 |
Table of Contents
Nalidixic Acid: From Antibacterial Therapy to Conjunctivitis
One-Sentence Summary
Nalidixic acid is a first-generation quinolone antibacterial; the evidence pack does not specify its original approved indication, and no UK marketing authorisation is currently on record for this product. The TxGNN model predicts it may be effective for Conjunctivitis, but this is currently supported by 0 clinical trials and only 6 tangential publications, none of which directly study nalidixic acid for this indication.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not specified in evidence pack (drug class: first-generation quinolone antibacterial) |
| Predicted New Indication | Conjunctivitis |
| TxGNN Prediction Score | 99.83% |
| Evidence Level | L4 |
| UK Market Status | Not marketed |
| Number of Marketing Authorisations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the evidence pack. Based on known drug class information, nalidixic acid is a first-generation quinolone that inhibits bacterial DNA gyrase, giving it antibacterial activity against certain Gram-negative organisms (e.g. Shigella species).
Bacterial conjunctivitis can, in principle, be caused by susceptible Gram-negative organisms, which is the theoretical basis for this prediction. However, none of the available literature directly evaluates nalidixic acid as a treatment for conjunctivitis — the retrieved publications instead describe pathogen characteristics (e.g. Tsukamurella pulmonis, Shigella isolates) or use nalidixic acid incidentally as a laboratory selective agent (e.g. Columbia nalidixic agar) or resistance marker. This is an indirect mechanistic inference rather than a demonstrated clinical link.
Clinical Trial Evidence
Currently no related clinical trials registered
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 34151142 | 2021 | Case Report | Access Microbiology | Two cases of Tsukamurella pulmonis conjunctivitis; nalidixic acid mentioned only as a component of the selective culture medium used for isolation, not as treatment. |
| 15824427 | 2005 | Microbiology/Isolation Study | Journal of Medical Microbiology | Characterisation of a novel Shigella boydii serovar from diarrhoeal patients; no direct link to conjunctivitis treatment. |
| 17446289 | 2007 | Microbiology/Isolation Study | Journal of Medical Microbiology | Description of a novel Shigella dysenteriae serovar; nalidixic acid not used therapeutically in this study. |
| 16914657 | 2006 | Microbiology/Resistance Study | Journal of Medical Microbiology | Reports >60% nalidixic acid resistance among Shigella sonnei isolates in Bangladesh (1999–2003), suggesting limited reliability against Gram-negative pathogens. |
| 9442487 | 1997 | Molecular/Plasmid Study | Microbial Drug Resistance | Plasmid-mediated drug resistance study in epidemic Shigella dysenteriae; nalidixic acid resistance used as a phenotypic marker only. |
| 3206956 | 1988 | In Vitro Study | Zhurnal Mikrobiologii, Epidemiologii i Immunobiologii | Yersinia virulence study; nalidixic acid resistance used as a strain-selection tool, not a therapeutic endpoint. |
UK Market Information
No UK marketing authorisations were found for nalidixic acid in the evidence pack (market status: Not marketed; total licenses: 0). This product does not currently appear on the UK market and no formulation or approved-indication data is available for review.
Safety Considerations
Please refer to the SmPC and BNF for safety information. Report suspected adverse reactions via the Yellow Card Scheme.
Conclusion and Next Steps
Decision: Hold
Rationale: There are no clinical trials and no direct literature support for nalidixic acid in conjunctivitis — all six retrieved publications reference the drug only as a laboratory reagent or resistance marker, not as a treatment. Combined with the absence of UK marketing authorisation, confirmed MOA data, and safety/contraindication data, the evidence is insufficient to proceed beyond a hypothesis-generating stage.
To proceed, the following is needed:
- Confirmed mechanism of action data (DrugBank/SmPC)
- Original approved indication(s) and regulatory history
- Direct preclinical or clinical evidence of nalidixic acid efficacy against organisms causing conjunctivitis
- UK marketing authorisation status confirmation (MHRA)
- Safety, contraindication, and drug interaction data (SmPC/BNF)
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.