Lidocaine
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Lidocaine: From Dermatitis and Neuralgia to Punctate Epithelial Keratoconjunctivitis
One-Sentence Summary
Lidocaine is a local anaesthetic that has been used for conditions such as dermatitis, neuralgia, postherpetic neuralgia, haemorrhoids and scabies. The TxGNN model predicts it may be effective for punctate epithelial keratoconjunctivitis (score 99.99%), but no clinical trials or publications currently support this prediction. This is a model prediction only, and the compiled data point to a possible safety concern (corneal toxicity of topical anaesthetics).
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Dermatitis, neuralgia, postherpetic neuralgia, haemorrhoids, scabies and related conditions (the Singapore licence records contain no approved indication text) |
| Predicted New Indication | Punctate epithelial keratoconjunctivitis |
| TxGNN Prediction Score | 99.99% |
| Evidence Level | L5 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 20 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data are not available in the data compiled for this report. Lidocaine is generally known as a sodium channel blocker, which interrupts nerve signalling and produces local anaesthesia. Its established uses are pain control and surface or infiltration anaesthesia, including in the eye.
Mechanistically, the link to punctate epithelial keratoconjunctivitis is weak. Easing ocular surface discomfort is conceivable, but this is a symptom-level effect, not a disease-modifying one. Topical anaesthetics are also known to be toxic to the corneal epithelium and can cause keratitis when misused, which argues against therapeutic use in this condition.
For context, other conditions among the top ten predictions show somewhat more activity. Conjunctival disorder has two completed trials and several publications, though they concern anaesthesia for eye surgery, not treatment of the disease. Atopic conjunctivitis has indirect preclinical evidence (sensory nerve involvement in allergen passage), which remains a hypothesis. These are noted only as secondary research directions.
Clinical Trial Evidence
Currently no related clinical trials registered for the predicted indication, punctate epithelial keratoconjunctivitis.
Literature Evidence
Currently no related literature available for the predicted indication.
Singapore Market Information
Lidocaine has 20 valid single-ingredient registrations. Approved indication text is not recorded in the licence data. Five main authorisations:
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN06314P | Lidocaine Gel 2% (with preservative) | Gel | Not recorded |
| SIN05684P | Xylocaine Jelly 2% | Gel | Not recorded |
| SIN05616P | Xylocaine Injection 1% (5 mL) | Injection | Not recorded |
| SIN06984P | Xylocaine Pump Spray 10% | Spray | Not recorded |
| SIN16833P | GP-Lidocaine Patch 5% w/w (700 mg/patch) | Patch | Not recorded |
Other registered forms include injection solutions, ointment, jelly and oromucosal spray. No ophthalmic-specific formulation is evident from the product names, so route compatibility for an ocular indication has not been assessed.
Safety Considerations
Package insert warnings and contraindications were not available for this report. Please refer to the package insert for label safety information.
Additional information from the compiled data:
- Disease associations flagged in the knowledge graph (not label text): hypertension, liver failure and cirrhosis, kidney disease, epilepsy, adrenocortical insufficiency, hypothyroidism, open-angle glaucoma, psychotic and mental disorders, herpes simplex virus keratitis, and others. These need verification against the official label.
- Drug interactions (100 recorded; examples):
- 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
- Literature safety signals: neuropsychiatric and cardiac side effects with intravenous lidocaine (PMID 19250287); methemoglobinemia in a child using topical lidocaine with other causative drugs (PMID 41995267); seizures in macaques after a ceftriaxone-lidocaine injection (PMID 19858165); keratitis associated with anaesthetic or drug misuse (PMID 8862924).
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction rests on the model score alone, with no trials or publications for punctate epithelial keratoconjunctivitis. The known corneal toxicity of topical anaesthetics is a safety signal pointing the other way.
To proceed, the following is needed:
- Mechanism of action data and a clear disease-specific hypothesis
- Package insert warnings and contraindications from the HSA, which block safety screening
- Preclinical or clinical evidence in ocular surface disease, including corneal epithelial safety
- Assessment of route and formulation compatibility (no ophthalmic product is evident in the Singapore registrations)
- Optionally, a separate evaluation of conjunctival disorder or atopic conjunctivitis as alternative research questions
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.