Ethosuximide
| Evidence Level: L5 | Predicted Indications: 1 |
Table of Contents
- Ethosuximide
- Ethosuximide: From Absence Seizures to Nephrogenic Syndrome of Inappropriate Antidiuresis
Ethosuximide: From Absence Seizures to Nephrogenic Syndrome of Inappropriate Antidiuresis
One-Sentence Summary
Ethosuximide is an anticonvulsant used for absence seizures. The TxGNN model predicts it may be effective for nephrogenic syndrome of inappropriate antidiuresis (NSIAD), but no clinical trials and no publications currently support this direction. The prediction is a model output only and has no mechanistic support in the available data.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Absence seizures (from the drug’s known use; the US license records do not list indication text) |
| Predicted New Indication | Nephrogenic syndrome of inappropriate antidiuresis |
| TxGNN Prediction Score | 99.91% |
| Evidence Level | L5 |
| US Market Status | ✓ Marketed |
| Number of NDAs | 11 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the source record. Ethosuximide is generally known as a T-type calcium channel (Cav3.x) blocker used for absence seizures.
NSIAD is caused by gain-of-function variants in AVPR2 (for example R137C or R137L). These make the vasopressin V2 receptor constitutively active. The result is higher cAMP, aquaporin-2 insertion into the membrane, and hyponatremia even though vasopressin is undetectable.
Nothing in the provided data links T-type calcium channel blockade to V2 receptor signaling or AQP2 trafficking. The very high TxGNN score is a knowledge-graph proximity signal only. Anticonvulsants as a class are more often associated with causing hyponatremia or SIADH-like effects than with treating them, so even the direction of any effect is unclear. The prediction is more likely a graph artifact, such as shared hyponatremia or antidiuresis neighbors, than a rational hypothesis.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available.
US Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| ANDA210654 | Ethosuximide (Epic Pharma, LLC) | Capsule | Not listed in the source record |
| ANDA200892 | Ethosuximide (Chartwell RX, LLC) | Capsule | Not listed in the source record |
| ANDA200892 | Ethosuximide (Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc.) | Capsule | Not listed in the source record |
| NDA012380 | Zarontin (Parke-Davis Div of Pfizer Inc) | Capsule | Not listed in the source record |
| ANDA080258 | Zarontin (Parke-Davis Div of Pfizer Inc) | Solution | Not listed in the source record |
The record lists 11 licenses in total. The table shows the first 5. Forms on the market include oral capsules, liquid-filled capsules and solution.
Safety Considerations
Please refer to the package insert for safety information. No drug interaction records were found in the source data.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction rests on the model score alone. There are no registered trials or publications, and the available data show no plausible link between T-type calcium channel blockade and the V2 receptor and AQP2 pathway underlying NSIAD. The class association with hyponatremia also raises doubt about the direction of any effect.
To proceed, the following is needed:
- Package insert warnings and contraindications (a blocking gap for safety screening)
- Confirmed mechanism of action data from DrugBank
- A literature and trial search for ethosuximide in hyponatremia, SIADH or NSIAD, including any preclinical evidence
- A mechanistic rationale connecting Cav3.x blockade to V2 receptor or AQP2 signaling, and a check on the direction of effect, before any further investment
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.