Lidocaine

Evidence Level: L5

Predicted Indications: 10

Lidocaine

Pharmacist Assessment Report

Lidocaine: From Local Anaesthesia and Neuralgia to Punctate Epithelial Keratoconjunctivitis

One-Sentence Summary

Lidocaine is a sodium channel–blocking local anaesthetic, with relations recorded in the knowledge graph for conditions such as dermatitis, neuralgia, postherpetic neuralgia, haemorrhoids and scabies. The TxGNN model predicts it may be effective for punctate epithelial keratoconjunctivitis, but no clinical trials and no publications directly study this disease, so the prediction rests on the model score alone.

Quick Overview

Item	Content
Original Indication	Relations recorded in the knowledge graph (not label text): dermatitis, neuralgia, postherpetic neuralgia, haemorrhoids, scabies and others. Licence records contain no indication text
Predicted New Indication	Punctate epithelial keratoconjunctivitis
TxGNN Prediction Score	0.9999
Evidence Level	L5
Canada Market Status	Marketed (marketed DINs on record: at least 19; cancelled: 1)
Number of DINs	at least 20
Number of approvals	At least 20 licences (the list may be partial)
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism of action data is not available in the data compiled for this report. Lidocaine is generally known as a voltage-gated sodium channel blocker that numbs sensory nerves, and it is used as a local anaesthetic.

The link to punctate epithelial keratoconjunctivitis is weak. Any plausible benefit would be symptomatic pain relief, not treatment of the underlying disease. Topical anaesthetics can also damage the corneal epithelium with prolonged use, which argues against a therapeutic role. The very high TxGNN score is a computational prediction only and is not backed by any trial or publication on this disease.

For reference, the other top-ranked predictions are also ocular or renal conditions (papillary conjunctivitis, rosacea conjunctivitis, exposure keratitis, atopic conjunctivitis, nephrotic syndrome). All of them are likewise at the L5 or low-evidence stage, except where noted below.

Clinical Trial Evidence

Currently no related clinical trials registered for punctate epithelial keratoconjunctivitis.

Literature Evidence

Currently no related literature available for punctate epithelial keratoconjunctivitis.

Canada Market Information

At least 20 single-ingredient lidocaine licences are valid in Canada; the list below is partial and shows 5 of them. The licence records contain no dosage form or approved indication text.

DIN	Product Name	Dosage Form	Approved Indication
02485311	LIDOCAINE	Not listed	Not listed
02372983	XYLOCAINE 0.5%	Not listed	Not listed
02422018	LIDOCAINE HYDROCHLORIDE INJECTION USP	Not listed	Not listed
02462443	LIDOCAINE INJECTION BP	Not listed	Not listed
02003767	XYLOCAINE SPRAY	Not listed	Not listed

Safety Considerations

Relations recorded in the knowledge graph (not label text): the knowledge graph lists contraindication relations with, among others, hypertension, liver failure and liver disease, cirrhosis, epilepsy, kidney disease, adrenocortical insufficiency, hypothyroidism, open-angle glaucoma, herpes simplex virus keratitis, varicella zoster infection, atopic eczema, osteoporosis, psychotic and other mental disorders, fungal infections and gastritis. These should be verified against the package insert.
Drug Interactions: 100 interactions were found. The main ones listed here are:
- Major: bupropion.
- Moderate: aprepitant, cimetidine, liposomal morphine, obeticholic acid, polyethylene glycol (3350 with electrolytes), picosulfuric acid, sodium sulfate.
- Minor: dexamethasone, kanamycin, neomycin, omeprazole, streptomycin, troglitazone.
Reported adverse events in the literature: neuropsychiatric and cardiac side effects with intravenous lidocaine (PMID 19250287); methemoglobinemia in a child with nephrotic syndrome using topical lidocaine, benzocaine and co-trimoxazole (PMID 41995267).

Package insert warnings and contraindications were not available; please refer to the package insert for full safety information.

Conclusion and Next Steps

Decision: Hold

Rationale: The prediction is supported only by a model score. No trial or publication studies lidocaine in punctate epithelial keratoconjunctivitis, so the evidence level is L5. The mechanism offers at most symptomatic relief, and prolonged topical anaesthetic use can harm the corneal epithelium.

To proceed, the following is needed:

Mechanism of action data and a clear rationale for the disease
Preclinical or clinical studies that directly address punctate epithelial keratoconjunctivitis, including corneal safety
Health Canada package insert warnings and contraindications, and approved indication text for the licences
Route and formulation compatibility assessment (ophthalmic use)

Note on other predictions: Among the other ranked predictions, only “conjunctival disorder” has substantial material (a completed Phase 4 trial and pterygium surgery studies). These concern procedural anaesthesia, not treatment of conjunctival disease, and the SUNCT/SUNA papers concern a headache syndrome. They may be worth considering as a separate research question, but they do not support the lead prediction.

Disclaimer

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