Prilocaine
| Evidence Level: L2 | Predicted Indications: 10 |
Table of Contents
Prilocaine: From Local Anesthesia to Neuralgia
One-Sentence Summary
Prilocaine is an amide-type local anesthetic, best known in combination with lidocaine as EMLA cream, used for topical/regional pain control. Among the 10 disease candidates generated by TxGNN for this drug, Neuralgia has by far the strongest evidence base — 12 clinical trials and 20 publications, including a completed Phase 2 study directly testing lidocaine/prilocaine cream in postherpetic neuralgia (PHN) — so it is the focus of this report. (The model’s #1-ranked candidate, papillary conjunctivitis, had zero supporting trials or literature and was excluded.)
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not documented in EU marketing data (drug is not currently EU-marketed); based on the evidence pack, Prilocaine’s established use is as a local anesthetic (sodium-channel blocker), typically combined with lidocaine (EMLA cream) |
| Predicted New Indication | Neuralgia |
| TxGNN Prediction Score | 99.34% |
| Evidence Level | L2 |
| EU Market Status | ✗ Not Marketed |
| Number of Authorizations | 0 |
| Recommended Decision | Proceed with Guardrails |
Why is This Prediction Reasonable?
Currently, detailed mechanism-of-action data for Prilocaine is not available in the evidence pack (flagged as a High-severity data gap). Based on the available evidence, Prilocaine is an amide-type local anesthetic that blocks voltage-gated sodium channels, most commonly used in a 1:1 eutectic mixture with lidocaine (EMLA cream) for topical/regional anesthesia prior to minor procedures.
Neuralgia — particularly postherpetic neuralgia (PHN) — is pathophysiologically driven by abnormal ectopic firing of damaged peripheral nerve fibers. Sodium-channel blockade directly suppresses this aberrant firing, giving a clear mechanistic bridge from Prilocaine’s known anesthetic action to a neuropathic-pain indication. This is not a purely theoretical link: lidocaine-prilocaine cream (EMLA) already has a decades-long clinical history of off-label use in PHN, documented across multiple cohort studies, case reports, and at least one completed Phase 2 trial.
The main caveat is that most existing evidence tests the lidocaine-prilocaine combination or prilocaine as an adjunct/pretreatment (e.g., before capsaicin patch application), rather than prilocaine as a standalone therapeutic agent for neuralgia. Component-specific efficacy data for prilocaine alone is therefore limited.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT00916942 | Phase 2 | Completed | 20 | Open-label pretreatment with lidocaine 2.5%/prilocaine 2.5% cream before capsaicin 8% patch (NGX-4010) in postherpetic neuralgia — direct prilocaine-containing intervention |
| NCT01540877 | N/A | Completed | 28 | Human experimental model combining capsaicin sensitization with local anesthetic (including prilocaine) C-fiber block to study neuropathic pain mechanisms |
| NCT06899438 | N/A | Completed | 38 | Prospective comparison of prilocaine injection vs. Botulinum Toxin A for myofascial pain syndrome |
| NCT06247592 | N/A | Unknown | 70 | 2% prilocaine-based greater occipital nerve block vs. pulsed radiofrequency in chronic migraine |
| NCT03220113 | Phase 1/2 | Unknown | 100 | Open-label combined dexamethasone/lidocaine/thiamine injection into trigeminal and occipital nerves for craniofacial neuralgia |
| NCT05411900 | Phase 2 | Unknown | 164 | RCT of Botulinum Toxin A for peripheral neuropathic pain in carpal tunnel syndrome (local anesthetic used as comparator/adjunct) |
| NCT01911377 | Phase 2 | Terminated | 12 | Botulinum Toxin A for allodynic neuropathic pain in spinal cord injury/MS |
| NCT03587220 | N/A | Completed | 44 | TRPV1 fiber desensitization by capsaicin, evaluated with topical local anesthetic pretreatment |
| NCT04914637 | N/A | Completed | 66 | Dry needling plus epidural steroid injection for chronic neck pain from cervical disc herniation |
| NCT02537951 | N/A | Completed | 10 | Pilot imaging study of intraepidermal nerve fibers in small fiber neuropathy (methodology study) |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 2616182 | 1989 | RCT | Pain | EMLA cream significantly improved pain intensity scores at 6h in patients with refractory postherpetic neuralgia |
| 22182397 | 2011 | RCT | BMC Anesthesiology | Lidocaine 2.5%/prilocaine 2.5% cream pretreatment improved tolerability of capsaicin 8% patch in PHN patients |
| 1430539 | 1992 | Review | J Dermatol Surg Oncol | Reviews EMLA (2.5% lidocaine + 2.5% prilocaine) as effective topical anesthetic, including use in postherpetic neuralgia |
| 10353509 | 1999 | Cohort | Pain | Single and repeated EMLA applications reduced spontaneous and evoked pain in 11 PHN patients |
| 2493878 | 1989 | Cohort | BMJ | Lignocaine-prilocaine cream reported effective in postherpetic neuralgia |
| 12378018 | 2002 | Cohort | J Korean Med Sci | Identifies prognostic factors (age, lesion area, pain duration) for development of PHN, informing target population |
| 2046584 | 1991 | Case report | Med J Aust | EMLA cream used for herpetic neuralgia pain relief |
| 1875823 | 1991 | Case report | Med J Aust | Further case correspondence on EMLA cream for herpetic neuralgia |
| 8695081 | 1996 | Case report | J Clin Anesth | Successful treatment of treatment-resistant postherpetic neuralgia with EMLA cream |
| 24310458 | 2013 | Clinical study | Turk Neurosurg | Evaluates invasive procedures (including local anesthetic blocks) for medically intractable genitofemoral/ilioinguinal neuralgia |
EU Market Information
Prilocaine currently has no EU marketing authorization on record in this evidence pack (market_status: Not marketed, 0 licenses). No approved product/indication text is available to summarize.
Safety Considerations
Please refer to the SmPC for safety information. No key warnings, contraindications, or drug-interaction data were available in this evidence pack — this is flagged as a Blocking data gap (DG001: TFDA/EU label warnings and contraindications not yet retrieved), which must be resolved before any safety-based go/no-go decision.
Conclusion and Next Steps
Decision: Proceed with Guardrails
Rationale: Neuralgia (particularly PHN) is supported by L2 evidence — a completed Phase 2 trial and multiple cohort/RCT publications — showing lidocaine-prilocaine combination cream provides meaningful pain relief, with a clear sodium-channel-blockade mechanism. However, prilocaine-specific (non-combination) efficacy data is limited, and safety/label data is entirely missing.
To proceed, the following is needed:
- Retrieve TFDA/EU SmPC warnings and contraindications (Blocking gap, DG001)
- Obtain confirmed mechanism-of-action data from DrugBank (High gap, DG002)
- Identify prilocaine-only (non-lidocaine-combination) efficacy data for neuralgia, if it exists
- Assess route/formulation compatibility (topical cream vs. injectable) for the neuralgia indication
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.