Tobramycin

證據等級: L5

預測適應症: 10 個

Tobramycin: From Bacterial Infections to Exposure Keratitis

One-Sentence Summary

Tobramycin is a well-established aminoglycoside antibiotic conventionally used against gram-negative bacterial infections (notably Pseudomonas aeruginosa). The TxGNN model predicts a possible signal for Exposure Keratitis, but this is currently supported only by 2 tangentially related clinical trials and 7 case-report/in-vitro publications, none of which directly test tobramycin in this indication.

Quick Overview

Item	Content
Original Indication	Bacterial infections (aminoglycoside antibiotic class) — specific Danish-approved indication text unavailable; drug is not currently marketed in Denmark
Predicted New Indication	Exposure Keratitis
TxGNN Prediction Score	99.93%
Evidence Level	L4
Denmark Market Status	Not Marketed
Number of Marketing Authorisations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism-of-action data for this candidate is currently unavailable. Based on established pharmacology, tobramycin is an aminoglycoside antibiotic that binds the bacterial 30S ribosomal subunit, inhibiting protein synthesis and producing bactericidal activity primarily against gram-negative organisms such as Pseudomonas aeruginosa. This mechanism underlies its long-standing use in ocular, respiratory, and systemic gram-negative infections.

Exposure keratitis, however, is fundamentally a mechanical/eyelid-closure disorder — corneal damage results from chronic surface drying and exposure rather than primary infection. Tobramycin’s plausible role would therefore be limited to preventing or treating a secondary bacterial infection superimposed on an already compromised cornea, not treating the underlying condition itself. This is an indirect mechanistic link rather than a direct one.

Notably, an in-vitro toxicity study in the evidence set (PMID 2707046) found that aminoglycosides including tobramycin can be cytotoxic to corneal epithelial cells, raising a specific concern that use in an already-damaged, exposed cornea could aggravate rather than protect the ocular surface. This tempers the otherwise high TxGNN prediction score and supports a cautious, evidence-gathering posture rather than immediate progression.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT06200727	N/A	Unknown	170	Evaluates platelet-rich fibrin (PRF) membrane across four ophthalmic conditions; does not evaluate tobramycin — graded low relevance (C)
NCT05313828	N/A	Unknown	40	Evaluates treatment modalities for herpes simplex virus (viral) dendritic corneal ulcer; tobramycin has no antiviral activity — graded low relevance (C)

Neither trial directly evaluates tobramycin for exposure keratitis.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
34987857	2021	Case report	Oxford Medical Case Reports	Bacterial keratitis from multi-drug-resistant Shewanella algae in a bedridden patient unable to close his eyes voluntarily (exposure-related risk factor)
11581057	2001	Case report	Ophthalmology	Bacillus cereus keratitis and ulcer associated with contact lens case contamination
2707046	1989	In vitro toxicity	Current Eye Research	Aminoglycosides (including tobramycin) show cytotoxicity to rabbit corneal epithelial cells in vitro — relevant safety signal for compromised corneas
33847093	2021	Retrospective (veterinary)	Polish Journal of Veterinary Sciences	Feline ocular toxoplasmosis case series; limited translational relevance to human exposure keratitis
12861116	2003	Case report	Eye & Contact Lens	Bilateral MRSA keratitis following photorefractive keratectomy
17228760	2006	In vitro (MIC/PAE)	Nippon Ganka Gakkai Zasshi	MIC/postantibiotic effect comparison of antibiotic eyedrops against infectious keratitis isolates in Japan
14574976	2003	Case report (non-infectious)	Yan Ke Xue Bao / Eye Science	Corneal dellen in Graves ophthalmopathy — non-infectious etiology, illustrative of exposure-type corneal pathology

All available literature is Tier 3 (case reports / in vitro data); no controlled studies specifically evaluate tobramycin for exposure keratitis.

Denmark Market Information

Tobramycin currently holds no marketing authorisations in Denmark — the drug is not marketed (Laegemiddelstyrelsen registration status: Not Marketed, 0 licenses on file).

Safety Considerations

Please refer to the approved Summary of Product Characteristics (SmPC) for safety information. Key warnings, contraindications, and drug-interaction data for this candidate were not available at the time of this evaluation.

Conclusion and Next Steps

Decision: Hold

Rationale: No clinical trial or literature source directly evaluates tobramycin’s efficacy in exposure keratitis; the two identified trials are unrelated to the drug, and supporting literature is limited to case reports and in-vitro data — one of which raises a corneal-toxicity concern rather than supporting benefit. Combined with the drug’s non-marketed status in Denmark, current evidence does not support progression beyond a preliminary hold.

To proceed, the following is needed:

Danish/SmPC-sourced warnings, contraindications, and drug interaction data (currently blocking safety pre-screening)
Confirmed mechanism-of-action documentation
Studies directly assessing tobramycin (or aminoglycoside topical therapy) in exposure keratitis, ideally addressing corneal epithelial safety in an already-compromised ocular surface
Clarification of intended route of administration (e.g., topical ophthalmic) and route compatibility assessment, which is currently unresolved
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.