Tiagabine
| Evidence Level: L4 | Predicted Indications: 1 |
Table of Contents
Tiagabine: From Partial Epilepsy to Visual Epilepsy
One-Sentence Summary
Tiagabine is an anticonvulsant originally used to treat partial epilepsy. The TxGNN model predicts it may be effective for visual epilepsy, but there are no registered clinical trials and the 17 publications compiled are mostly general reviews of tiagabine or antiseizure drugs, not studies of visual epilepsy specifically.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Partial epilepsy |
| Predicted New Indication | Visual epilepsy |
| TxGNN Prediction Score | 99.25% |
| Evidence Level | L4 |
| US Market Status | Cancelled only (no currently valid licenses) |
| Number of NDAs | 3 (all cancelled) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. From general pharmacological knowledge, tiagabine is a selective GABA reuptake inhibitor (GAT-1). It raises synaptic GABA levels and is established for partial seizures. The reviews on its mechanism (Schachter 1999; Treiman 2001 on GABAergic mechanisms in epilepsy) are consistent with this.
Visual (photosensitive or occipital) epilepsy is a focal epilepsy type, so it is closely related to the original indication of partial epilepsy. Boosting GABA inhibition could plausibly help in it as well.
However, the very high TxGNN score most likely reflects how close the two diseases are in the knowledge graph, not independent evidence for visual epilepsy. The visual-field literature (vigabatrin, tiagabine and visual fields; antiepileptic drugs and visual function) concerns adverse effects on vision, not efficacy. It is a possible safety consideration, not supporting evidence. One review on drug-induced status epilepticus also notes that GABAergic antiseizure drugs, tiagabine among them, can worsen seizures in some epilepsy types.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 29898971 | 2018 | Guideline | Neurology | AAN/AES practice guideline update on newer antiepileptic drugs for new-onset epilepsy |
| 32120063 | 2020 | Review | Neuropharmacology | Mechanisms of action of currently used antiseizure drugs |
| 10530690 | 1999 | Review | Epilepsia | Tiagabine inhibits GABA reuptake; effective as add-on therapy for partial seizures; no clinically relevant effect on hepatic metabolism or other AED levels |
| 9097364 | 1997 | Review | Seminars in Pediatric Neurology | Effective against partial seizures in adults and adolescents; preliminary pediatric data encouraging |
| 15094857 | 1998 | Review | Drugs of Today | Unique GABA uptake mechanism; efficacious in animal seizure models; no evidence of teratogenicity, carcinogenicity or mutagenicity in animals |
| 12588906 | 2003 | Review | J Neurol Neurosurg Psychiatry | Vigabatrin, tiagabine and visual fields (adverse-effect topic; no abstract available) |
| 17560495 | 2007 | Review | Pediatric Neurology | Antiepileptic drugs and visual disturbances, particularly visual field and colour vision deficits |
| 11520315 | 2001 | Review | Epilepsia | GABAergic mechanisms in epilepsy |
| 26210064 | 2015 | Review | Epilepsy & Behavior | Drug-induced status epilepticus; GABAergic drugs including tiagabine may exacerbate seizures in some epilepsies |
| 10915031 | 2000 | Review | Drug Safety | Adverse reactions to newer anticonvulsants |
US Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| NDA020646 (cancelled) | Tiagabine Hydrochloride (Teva) | Film-coated tablet | Not specified |
| ANDA214816 (cancelled) | Tiagabine Hydrochloride (Novadoz) | Tablet | Not specified |
| ANDA077555 (cancelled) | Tiagabine Hydrochloride (Sun Pharmaceutical) | Film-coated tablet | Not specified |
Safety Considerations
- Contraindications flagged in the knowledge graph (not label text): anxiety disorder, neurotic disorder, dysthymic disorder, liver disease, gallbladder disease.
- Drug Interactions: 97 interactions were identified. Those rated Moderate include aprepitant, morphine (including liposomal), dronabinol, nabilone, metoclopramide and opium. Others are of unknown severity, for example pantoprazole, omeprazole, metformin, simvastatin and ondansetron.
- Visual effects: the literature on tiagabine and visual fields suggests visual function should be considered in any visual-epilepsy study.
- Seizure exacerbation: GABAergic antiseizure drugs, including tiagabine, can worsen seizures in some epilepsy types.
Please refer to the package insert for full safety information, as label warnings and contraindications were not available.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction rests on a model score and general mechanistic plausibility. There are no clinical trials and no literature showing efficacy in visual epilepsy. In addition, all US licenses are cancelled and label safety data is missing.
To proceed, the following is needed:
- FDA package insert warnings and contraindications
- Mechanism of action data confirmed from DrugBank
- Disease-specific evidence for visual (photosensitive or occipital) epilepsy, such as case series or preclinical models
- Assessment of visual-field safety and seizure-exacerbation risk
- Review of the cancelled US market status, including the practical availability of the drug
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.