Prilocaine
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Prilocaine: From Premature Ejaculation to Papillary Conjunctivitis
One-Sentence Summary
Prilocaine is an amide-type local anaesthetic. The knowledge-graph records link it to premature ejaculation and psychologic dyspareunia, and it is marketed in Singapore in injectable, cream and spray forms. The TxGNN model predicts it may be effective for papillary conjunctivitis, with a very high score (99.78%). Currently 0 clinical trials and 0 publications support this specific prediction, so it is a model prediction only.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Premature ejaculation; psychologic dyspareunia (from knowledge-graph indication records; the Singapore licence entries do not state an indication text) |
| Predicted New Indication | Papillary conjunctivitis |
| TxGNN Prediction Score | 99.78% |
| Evidence Level | L5 (model prediction only) |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 5 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism-of-action data is not available in the data compiled for this report. Prilocaine is known as a sodium channel-blocking amide local anaesthetic. By blocking nerve conduction, it produces surface or local anaesthesia. Its established uses are in dermal, dental and procedural anaesthesia, and its knowledge-graph indications relate to genital sensitivity and pain.
A surface anaesthetic effect on ocular discomfort is conceivable. However, papillary conjunctivitis is mainly an allergic or mechanical inflammatory condition, for example from contact lens wear or allergy. Anaesthesia would at most relieve symptoms and would not treat the underlying inflammation. The link to the original indications is therefore weak. No trial or publication supports prilocaine in this condition, and the high model score should not be read as clinical evidence.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available.
Singapore Market Information
| Authorization Number | Product Name | Dosage Form |
|---|---|---|
| SIN16326P | TAKIPRIL Solution for Injection 20 mg/ml | Injection, solution |
| SIN16538P | FORTACIN Cutaneous Spray Solution 7.5 mg/dose + 2.5 mg/dose | Spray, metered |
| SIN14852P | RACSER Cream 5% | Cream |
| SIN06443P | EMLA Cream 5% | Cream |
| SIN06175P | CITANEST OCTAPRESSIN Injection | Injection |
All five licences are valid single-ingredient registrations, and none has been cancelled. No licence is for an ophthalmic dosage form.
Safety Considerations
- Conditions flagged in the knowledge graph as contraindicated or to be avoided (these come from drug–disease relationship records, not package insert text):
- Cardiovascular: hypertension, coronary artery disease, myocardial infarction, heart conduction disease, atrioventricular block, sudden cardiac arrest
- Neurological and neuromuscular: epilepsy, myasthenia gravis and other neuromuscular junction diseases
- Metabolic and endocrine: diabetes mellitus, diabetic ketoacidosis, hyperthyroidism and Graves disease
- Organ disease: kidney, liver and gallbladder disease, and respiratory failure
- Blood and enzyme disorders: hemoglobinopathy, butyrylcholinesterase deficiency
- Eye: angle-closure glaucoma
- Drug interactions: 22 interactions are recorded. Most of the listed ones are rated Major.
- Major interactions include metoclopramide, sulfasalazine, amyl nitrite, rasburicase, nitrous acid, nitric oxide, chloroquine, primaquine, quinine, tafenoquine, dapsone (systemic and topical), other local anaesthetics (lidocaine, topical lidocaine, topical benzocaine, topical cinchocaine), and topical silver nitrate and silver sulfadiazine.
- Morphine (liposomal) is rated Moderate, and hyaluronidase is rated Minor.
- Many of these agents are associated with methemoglobinaemia, so combined use warrants caution.
- Ocular use: none of the Singapore products is an ophthalmic formulation, and no ocular safety data were compiled. Any eye use would need a dedicated safety assessment.
Please also refer to the package insert for the full warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction rests only on a model score. No clinical trials or publications were found, no ocular formulation is registered, and the mechanistic link to an allergic or mechanical inflammatory eye condition is weak.
Among the other predictions in the same analysis, neuralgia (including postherpetic neuralgia) has the most supporting evidence. It has small, older studies of lidocaine/prilocaine cream, graded L2, and could be a better candidate to explore first. These studies are mostly uncontrolled and the lidocaine combination confounds them.
To proceed, the following is needed:
- Any preclinical or clinical evidence of benefit in papillary conjunctivitis
- Detailed mechanism-of-action data
- Package insert warnings and contraindications from the Singapore regulator
- An ophthalmic formulation and its ocular safety and tolerability data
- A comparison against existing treatments for papillary conjunctivitis, such as antihistamines and mast-cell stabilisers
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.