Phenindione
| Evidence Level: L3 | Predicted Indications: 1 |
Table of Contents
Phenindione: From Anticoagulant Therapy (Discontinued) to Thrombotic Disease
One-Sentence Summary
Phenindione is an indanedione-class vitamin K antagonist historically used as an oral anticoagulant, but it has been discontinued in most markets due to a higher incidence of severe adverse effects than warfarin. The TxGNN model predicts renewed relevance for Thrombotic Disease, but this is essentially the drug’s own historical indication rather than a novel signal, and the current evidence base is 1 loosely related clinical trial and 20 publications, most of which concern the vitamin K antagonist (VKA) class in general rather than phenindione specifically.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Anticoagulant / thromboembolism prophylaxis (VKA) — historical use, discontinued in most markets due to safety concerns; no India/Taiwan license record found |
| Predicted New Indication | Thrombotic disease |
| TxGNN Prediction Score | 99.29% |
| Evidence Level | L3 |
| India Market Status | ✗ Not marketed |
| Number of Registrations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
The original_moa field is not populated in this evidence pack, but the pharmacology data captured under drug-target interactions clarifies the mechanism: phenindione targets VKORC1 (vitamin K epoxide reductase complex subunit 1), the same target as warfarin, acenocoumarol, and fluindione. Inhibiting VKORC1 blocks the recycling of vitamin K, which in turn suppresses hepatic synthesis of clotting factors II, VII, IX, and X — the classic vitamin K antagonist anticoagulant mechanism.
Because thrombotic disease is precisely the therapeutic area VKAs were designed for, the mechanistic link to the “predicted” indication is strong — arguably too strong to be a genuine repurposing discovery. Phenindione already has a documented anticoagulant clinical history; the pharmacology record notes it is an “anticoagulant — discontinued due to higher incidence of severe adverse effects than warfarin,” with no current FDA or EMA marketing approval and uncertain status elsewhere. In other words, this candidate is a rediscovery of a known-but-withdrawn indication rather than a novel mechanistic hypothesis, which changes the framing from “efficacy validation” to “risk-benefit re-evaluation.”
The literature reinforces this: the available publications are overwhelmingly about the VKA class as a whole (warfarin, fluindione, acenocoumarol) rather than phenindione-specific trials, and several directly describe serious phenindione-related hypersensitivity reactions from historical case series.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT05646394 | N/A (Registry) | Recruiting | 150 | Registry study on antithrombotic regimens (VKA ± aspirin vs. dual antiplatelet) in antiphospholipid syndrome patients with a recent arterial event. Not a phenindione-specific interventional trial — relevance graded “C” (observational, same drug class only). |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 13162792 | 1954 | Case Report | JAMA | Severe drug sensitivity reaction directly attributed to phenindione (phenylindandione) — earliest direct safety signal for this drug. |
| 13307153 | 1956 | Clinical Report | J Med Assoc Georgia | Early clinical description of phenylindanedione as an anticoagulant. |
| 8037888 | 1994 | Review | Drug Safety | Review of clinically significant drug interactions with oral anticoagulants, including indanedione derivatives. |
| 41177211 | 2025 | Review (systematic) | Contraception | Updated systematic review on safety of contraception in women using anticoagulant therapy (bleeding/thrombosis risk). |
| 24889788 | 2014 | Cohort | J Mal Vasc | Case-control analysis of risk factors for thrombotic or bleeding events in VKA-treated patients. |
| 12503504 | 2002 | Cohort | Arch Pediatr | Acenocoumarol and fluindione use in 150 children after cardiac surgery. |
| 17176918 | 2006 | Case Report | Clin Nephrol | Acute immuno-allergic interstitial nephritis caused by fluindione (VKA-class hypersensitivity reaction, analogous to phenindione’s known AE profile). |
| 21978501 | 2011 | Case Report | Ann Dermatol Venereol | Five cases of necrotic leg ulcers induced by vitamin K antagonists. |
| 14714343 | 2003 | Cohort | Ann Cardiol Angeiol | Evaluation of a patient education program for oral anticoagulation therapy. |
| 21531328 | 2011 | Review | Adv Chronic Kidney Dis | Review of nephrotoxins, including thrombotic microangiopathy as a drug-induced vascular injury pattern. |
India Market Information
Phenindione has 0 registrations and is currently not marketed in the available regulatory dataset — no license records were returned.
Safety Considerations
- Known Safety Signal (pharmacology database): Phenindione has been discontinued in multiple markets due to a higher incidence of severe adverse effects than warfarin; no current FDA or EMA marketing approval is on record, though individual national agencies may still authorize it.
- Historical Case Evidence: A severe drug sensitivity reaction to phenindione was documented as early as 1954 (PMID 13162792).
- Class-Related Adverse Events (from VKA analogs): Hypersensitivity-mediated interstitial nephritis (fluindione, PMID 17176918) and necrotic skin ulcers (VKA class, PMID 21978501) have been reported for structurally related vitamin K antagonists.
- Official warnings and contraindications are not available in this evidence pack (TFDA label data collection is flagged as a blocking gap — see Conclusion).
Conclusion and Next Steps
Decision: Hold
Rationale: This is not a novel mechanistic prediction but a resurfacing of phenindione’s own original — and clinically discontinued — anticoagulant indication. Evidence is L3 (observational/class-level literature, no phenindione-specific RCTs), and the drug’s documented history of severe hypersensitivity reactions relative to warfarin outweighs the mechanistic plausibility of the “prediction” until safety data is reviewed.
To proceed, the following is needed:
- TFDA/CDSCO label data (warnings, contraindications) — currently a blocking data gap preventing S1 safety screening
- Confirmed original mechanism-of-action documentation (beyond the inferred VKORC1 target from pharmacology data)
- Phenindione-specific (not VKA-class) clinical evidence for thrombotic disease, ideally contemporary Phase 2/3 data
- A formal comparative safety assessment against warfarin/DOACs before any “Go” consideration
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.