Carbamazepine
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Carbamazepine: From Epilepsy and Trigeminal Neuralgia to Trigeminal Nerve Neoplasm
One-Sentence Summary
Carbamazepine is a sodium channel–blocking antiseizure drug, originally used for epilepsy, bipolar disorder and trigeminal neuralgia. The TxGNN model predicts it may be effective for trigeminal nerve neoplasm (score 99.998%), but there are no registered clinical trials and the 20 publications retrieved are mostly case reports and reviews of tumour-related neuralgia. Evidence is model prediction only (L5).
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Epilepsy (including partial and generalized tonic-clonic seizures), bipolar disorder (manic), trigeminal neuralgia, glossopharyngeal neuralgia, Lennox-Gastaut syndrome (from the knowledge graph; the Singapore licence records contain no indication text) |
| Predicted New Indication | Trigeminal nerve neoplasm |
| TxGNN Prediction Score | 99.998% |
| Evidence Level | L5 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 6 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data are not available in the data compiled for this report. From general pharmacology, carbamazepine is an established treatment for trigeminal neuralgia and is understood to act by blocking voltage-gated sodium channels, which suppresses abnormal neuronal firing.
The link to the predicted indication is weak. The retrieved literature concerns trigeminal neuralgia caused by tumours or lesions (schwannoma, meningioma, lipoma, dermoid cyst, lymphoma, melanoma, pituitary adenoma). In these cases carbamazepine can at most relieve pain symptomatically. Several reports describe patients whose pain was not controlled by carbamazepine, which in some cases led to the discovery of the tumour. There is no evidence that it treats the neoplasm itself. The high TxGNN score most likely reflects the closeness of "trigeminal nerve neoplasm" to "trigeminal neuralgia" in the knowledge graph rather than a true anti-tumour effect.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
The 20 retrieved publications comprise 2 reviews, 8 case reports, and the remainder unclassified or preclinical items. No RCTs were found. Representative items are listed below.
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 36824641 | 2022 | Review | Acta Clin Croat | Treatment options for trigeminal neuralgia, which can be caused by vascular compression or a tumour |
| 17997704 | 2007 | Review | Expert Rev Neurother | Medical and surgical treatments for trigeminal neuralgia |
| 30741017 | 2023 | Case report | Br J Neurosurg | Primary lymphoma of the trigeminal nerve; carbamazepine did not improve symptoms |
| 25142539 | 2014 | Case report | Rinsho Shinkeigaku | Lymphoma spreading along the trigeminal nerve; initial pain improved with carbamazepine, then became ineffective |
| 25433061 | 2014 | Case report | No Shinkei Geka | Neuralgia from a cerebellopontine angle lipoma; carbamazepine limited by side effects |
| 15235745 | 2004 | Case report | Arq Neuropsiquiatr | Primary melanoma of Meckel's cave; pain not relieved by carbamazepine |
| 33989821 | 2021 | Case report | World Neurosurg | Petroclival meningioma causing trigeminal neuralgia, resected surgically |
| 22647513 | 2012 | Case report | No Shinkei Geka | Combined glossopharyngeal and trigeminal neuralgia; carbamazepine is first-line, surgery if it fails |
| 3181365 | 1988 | Preclinical | Exp Neurol | Carbamazepine inhibits spontaneous activity in experimental rat neuromas (a pain mechanism, not tumour control) |
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN02388P | Tegretol CR 400 Tablet 400 mg | Tablet, film coated | Not recorded |
| SIN05735P | Apo-Carbamazepine Tablet 200 mg | Tablet | Not recorded |
| SIN00352P | Tegretol 200 Tablet 200 mg | Tablet | Not recorded |
| SIN05583P | Storilat 200 Tablet 200 mg | Tablet | Not recorded |
| SIN02387P | Tegretol CR 200 Tablet 200 mg | Tablet, film coated | Not recorded |
A sixth licence, Tegretol Oral Suspension 2% (SIN00510P, suspension), is also valid. All six are single-ingredient products and none has been cancelled.
Cytotoxicity
Not applicable. Carbamazepine is not an antineoplastic drug.
Safety Considerations
- Contraindications and risk conditions (from the knowledge graph, not label text): the following conditions are linked to carbamazepine as contraindicated or high-risk:
- Blood disorders: neutropenia, agranulocytosis, pancytopenia, thrombocytopenia, anaemia, and congenital neutropenia syndromes.
- Cardiac conditions: atrioventricular block, heart conduction disease, coronary artery disease, and sudden cardiac arrest.
- Organ disease: liver disease, kidney disease and impaired renal function, and gallbladder disease.
- Other: glaucoma and ocular hypertension, inappropriate ADH syndrome, absence epilepsy, and anxiety or dysthymic disorders.
- Drug Interactions: 100 interactions were found. Major interactions include clarithromycin and eliglustat. Moderate interactions include doxycycline, corticosteroids (hydrocortisone, dexamethasone, betamethasone, triamcinolone), vitamin D analogues, pioglitazone, bupropion, aprepitant, morphine, metronidazole, cimetidine, canagliflozin and activated charcoal.
Please refer to the package insert for the official warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction rests on knowledge-graph proximity alone. The literature shows carbamazepine only as symptomatic pain treatment in tumour-associated neuralgia and often as ineffective. There are no trials, and no evidence of an effect on the tumour. The drug also carries notable haematological, cardiac and interaction risks.
To proceed, the following is needed:
- Package insert warnings and contraindications for the Singapore licences. This gap blocks safety screening.
- Mechanism of action data (for example from DrugBank).
- Evidence of a direct anti-tumour effect, or a clear reframing of the question as symptomatic pain control in tumour-related trigeminal neuralgia. That use is already covered by the existing trigeminal neuralgia indication.
Other Predicted Indications (Context)
The model also ranked several reflex-seizure conditions highly. These are largely subtypes of epilepsy that the approved indications already cover. They are not covered by the decision above and each has its own recommendation.
| Predicted Indication | TxGNN Score | Evidence Level | Recommendation | |------|------|------|------| | Audiogenic seizures | 99.97% | L4 (animal studies only) | Research Question | | Startle epilepsy | 99.97% | L4 (case series and cohort, one study reporting carbamazepine response in focal startle seizures) | Research Question | | Reading seizures | 99.97% | L4 (indirect) | Research Question | | Eating seizures | 99.97% | L5 | Hold | | Orgasm-induced seizures | 99.97% | L5 (no literature) | Hold | | Thinking seizures | 99.97% | L5 | Hold | | Micturition-induced seizures | 99.97% | L5 | Hold | | Beta-ketothiolase deficiency | 99.89% | L5 (no mechanistic link) | Hold | | Rett syndrome, congenital variant | 99.87% | L5 | Hold |
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.