Digoxin

Evidence Level: L5

Predicted Indications: 5

Digoxin

Pharmacist Assessment Report

Digoxin: Cardiac glycoside (Na+/K+-ATPase inhibitor) → Prinzmetal angina (Prinzmetal angina)

One-Sentence Summary

Digoxin is a cardiac glycoside available in Australia as an oral tablet. The TxGNN model predicts it may be relevant to Prinzmetal angina, but no clinical trials and only 1 loosely related publication were found, so the prediction is not supported by direct evidence.

Quick Overview

Item	Content
Original Indication	Not recorded in the local data
Predicted New Indication	Prinzmetal angina
TxGNN Prediction Score	0.9981
Evidence Level	L5
Australia Market Status	Listed on the PBS Schedule (1 of 1 items) – TGA (ARTG) registration status is not included in this data
Number of PBS Items	1 (valid: 1)
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism of action data are not available in the data compiled for this report. Digoxin is generally understood to inhibit the Na+/K+-ATPase pump, which raises intracellular calcium in cardiac muscle.

For Prinzmetal angina, which is caused by coronary vasospasm, this mechanism does not offer a clear link. In theory, increased intracellular calcium could raise vascular tone, and cardiac glycosides are generally not favoured in vasospastic angina. The high TxGNN score is a model-based prediction only and is not backed by mechanistic or clinical evidence.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
10736610	1999	Review	Acta Physiol Pharmacol Bulg	General review of chronopharmacology and antihypertensive treatment; it does not address digoxin in Prinzmetal angina

Australia Market Information

ARTG Number	Product Name	Dosage Form	Approved Indication
ARTG 1322N	Lanoxin	Tablet 250 micrograms	Not recorded in the local data

Safety Considerations

Warning and contraindication text is not available in the data compiled for this report. Please refer to the TGA-approved Product Information (PI) for safety information.

Drug Interactions: An interaction screen returned 100 interacting drugs. Examples flagged as moderate include:

Acarbose, rabeprazole, doxycycline, tetracycline, metformin
Epinephrine, bupropion, acetylsalicylic acid, cholecalciferol, calcium phosphate
Amphotericin B (including lipid complex)
Corticosteroids: hydrocortisone, triamcinolone, dexamethasone, betamethasone

Minor interactions include albiglutide, hyoscyamine, atropine and glycopyrronium.

Conclusion and Next Steps

Decision: Hold

Rationale: No clinical trial or publication directly studies digoxin in Prinzmetal angina, so the evidence level is L5. The high model score is not supported by a plausible mechanism, and cardiac glycosides are generally not favoured in vasospastic angina.

To proceed, the following is needed:

Mechanistic evidence supporting a role in coronary vasospasm
Direct clinical or preclinical studies in Prinzmetal angina
Review of TGA Product Information warnings and contraindications
A safety assessment covering digoxin’s narrow therapeutic window and the interactions listed above
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.