Tobramycin

Evidence Level: L4

Predicted Indications: 10

Tobramycin

Pharmacist Assessment Report

Tobramycin: From Bacterial Eye and Meningeal Infections to Exposure Keratitis

One-Sentence Summary

Tobramycin is an aminoglycoside antibiotic, originally used for bacterial infections including conjunctivitis, uveitis-related eye conditions, Staphylococcus aureus infection, and bacterial meningitis. The TxGNN model predicts it may be effective for exposure keratitis, but there are no clinical trials and only 8 publications, mostly case reports and laboratory studies that are indirect or even raise toxicity concerns.

Quick Overview

Item	Content
Original Indication	Bacterial meningitis, uveitis, conjunctivitis, Staphylococcus aureus infection and related conditions (the approved indication text was not provided in the registration records)
Predicted New Indication	Exposure keratitis
TxGNN Prediction Score	0.9993
Evidence Level	L4
India Market Status	Listed in a compiled Indian medicine price dataset (at least 20) – CDSCO approval status is not included in this data
Number of Listed Products	at least 20
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism of action data is not available in the data compiled for this report. Based on general knowledge, tobramycin is a broad-spectrum aminoglycoside that inhibits bacterial protein synthesis by binding the 30S ribosomal subunit. It is already used topically for bacterial eye infections.

Exposure keratitis is a corneal surface disorder caused by incomplete eyelid closure and drying. A damaged corneal surface is prone to secondary bacterial infection, so antibacterial coverage is plausible. The link is to infection prevention or treatment, not to the underlying disease.

There is also a counterpoint. Laboratory work shows aminoglycosides can be toxic to corneal epithelial cells, which is a concern when the epithelium is already compromised.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
42842711	2026	Retrospective cohort	Cornea	Compared outcomes of MRSA and MSSA Staphylococcus aureus keratitis
2707046	1989	In vitro study	Current Eye Research	Compared corneal epithelial cell toxicity of four aminoglycosides, including tobramycin
17228760	2006	In vitro study	Nippon Ganka Gakkai Zasshi	Compared MIC and post-antibiotic effect of eye drops against isolates from infectious keratitis in Japan
11581057	2001	Case report	Ophthalmology	Contact lens-related Bacillus cereus keratitis
34987857	2021	Case report	Oxford Medical Case Reports	Multidrug-resistant Shewanella algae keratitis in a patient unable to close the eyes
12861116	2003	Case report	Eye & Contact Lens	Bilateral MRSA keratitis after photorefractive keratectomy
14574976	2003	Case report	Yan Ke Xue Bao	Corneal dellen as a sign of Graves ophthalmopathy
42358321	2026	In vitro study (veterinary)	Frontiers in Veterinary Science	Effect of fluorometholone on antibiotic susceptibility of canine ocular bacteria

India Market Information

Registration records do not include approved indication text. The 5 listed below are examples of the 20 valid registrations, covering injectable and ophthalmic forms.

Authorization Number	Product Name	Dosage Form	Approved Indication
164085	Optob Eye Drop	Eye drop, 5 ml packet	Not stated
224738	Tobnax Eye Drop	Ophthalmic solution, 5 ml bottle	Not stated
226095	Tobica Eye Drop	Eye drop, 5 ml packet	Not stated
223739	Toracin 80mg Injection	Injection, 2 ml vial	Not stated
18787	Aktob 80mg Injection	Injection, 2 ml vial	Not stated

Ophthalmic products are already available, so a topical route for an eye indication would not require a new dosage form.

Safety Considerations

Contraindications (from the knowledge graph, not label text): The drug-disease database lists conditions including kidney disease, myasthenia gravis and other neuromuscular junction disorders, Parkinson disease, herpes simplex virus keratitis, glaucoma, ocular hypertension, fungal and viral eye infections, ocular tuberculosis, and ophthalmic herpes zoster. Several of these are eye conditions and should be checked carefully against any corneal indication.
Drug Interactions: 131 interactions were identified. Major interactions include magnesium sulfate and mannitol. Moderate interactions include amphotericin B, vancomycin, kanamycin, neomycin, aspirin, and several proton pump inhibitors (omeprazole, pantoprazole, lansoprazole, rabeprazole, dexlansoprazole). These are mainly relevant to systemic use.
Corneal toxicity: Laboratory data show aminoglycosides can harm corneal epithelial cells, which matters for a disease with a damaged epithelium.

Conclusion and Next Steps

Decision: Hold

Rationale: The prediction score is very high, but there are no clinical trials and the literature is indirect (case reports of bacterial keratitis and laboratory studies). One laboratory study points to potential corneal epithelial toxicity. Tobramycin may help only with secondary infection, not with exposure keratitis itself.

To proceed, the following is needed:

Package insert warnings and contraindications for the marketed eye products (currently missing, and a blocking gap for safety screening)
Detailed mechanism of action data
Clinical data on tobramycin use in exposure keratitis, especially its effect on infection rates and corneal healing
A safety assessment of corneal epithelial toxicity with topical use in a compromised cornea
Review of the knowledge-graph contraindications against the eye conditions listed above
Disclaimer

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