Verapamil
| Evidence Level: L5 | Predicted Indications: 7 |
Table of Contents
Verapamil: From Hypertension and Arrhythmia to Obsolete Bundle Branch Block
One-Sentence Summary
Verapamil is an L-type calcium channel blocker, originally used for hypertension, atrial fibrillation, angina and ventricular tachycardia. The TxGNN model predicts it may be effective for obsolete bundle branch block (a deprecated disease term), but this rests on the model score alone, with 0 clinical trials and 0 publications supporting this direction.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Hypertension, atrial fibrillation, acute coronary syndrome, Prinzmetal angina, ventricular tachycardia (from the knowledge graph; no approved-indication text is available from the New Zealand licences) |
| Predicted New Indication | Obsolete bundle branch block |
| TxGNN Prediction Score | 99.62% |
| Evidence Level | L5 |
| New Zealand Market Status | Cancelled only (no currently valid authorizations) |
| Number of Authorizations | 6 (all cancelled) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Based on known information, verapamil is a calcium channel blocker, and its efficacy in hypertension and supraventricular and ventricular arrhythmias is established. Data compiled for this report show it acts on L-type calcium channels (Cav1.1–1.4) and also interacts with other ion channels and CYP3A4.
The link to the predicted indication is weak. Verapamil slows atrioventricular nodal conduction. Bundle branch block is a conduction defect in the His-Purkinje system, so slowing conduction could worsen it rather than treat it. The very high score (99.62%) is a graph-based prediction only, and the disease term is marked obsolete, so there is no clear clinical target.
Other top-ranked predictions are closer to the original indication but also lack clinical data:
- Malignant hypertensive renal disease (99.27%) and malignant renovascular hypertension (99.27%): plausible through vasodilation, but non-dihydropyridine calcium channel blockers are not first-line for malignant hypertension. The two publications retrieved for the latter are tangential (aldosterone/renin ratio confounders; a paediatric renal myofibromatosis case).
- Pulmonary hypertension (two subtypes, 99.26%): calcium channel blockers may help vasoreactive subsets, but verapamil's negative inotropic effect carries a risk of right heart failure. In lung disease or hypoxia, blunting hypoxic vasoconstriction may impair gas exchange.
- Braddock syndrome (99.15%) and periodic paralysis with transient compartment-like syndrome (99.08%): no clear mechanistic link or only a speculative one.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available for the top-ranked prediction. Literature retrieved for lower-ranked predictions is mostly off-target (arrhythmia reviews, migraine, retinal neuroprotection, in vitro and animal hypoxia studies) and does not test verapamil in the predicted conditions.
New Zealand Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| 2579391 | Isoptin Retard | Tab long-acting 120 mg | Not available |
| 2571897 | Isoptin SR | Tab long-acting 120 mg | Not available |
| 2535327 | Isoptin | Tab 40 mg | Not available |
| 2535351 | Isoptin | Inj 2.5 mg per ml, 2 ml ampoule | Not available |
| 2535343 | Isoptin SR | Tab long-acting 240 mg | Not available |
All six authorizations are cancelled; one further cancelled licence (2535335, Isoptin Tab 80 mg) is not listed above.
Safety Considerations
- Contraindications suggested by the knowledge graph (graph associations, not label text): heart failure, atrioventricular block, hypotensive disorder, aortic stenosis, hypertrophic cardiomyopathy, ventricular tachycardia (certain forms), myasthenia gravis and other neuromuscular junction disease, kidney disease, liver disease, gallbladder disease, angioedema (several forms), neutropenia, agranulocytosis, renal artery obstruction, and connective tissue, bone and cartilage disease.
- Drug Interactions: The interaction query returned 13 entries, which are pharmacological target interactions rather than graded drug-drug interactions. They include L-type calcium channels (Cav1.1–1.4), two-pore channels (TPC1, TPC2), several potassium channels (Kir3.2, Kv1.7, Kv1.8, Kv3.2), NALCN, the plasma membrane monoamine transporter, and CYP3A4. CYP3A4 is the most clinically relevant for co-medication. The records also note that verapamil improved the in vitro activity of another agent against Mycobacterium tuberculosis and M. abscessus.
Please refer to the package insert for full warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction is supported only by a model score. There are no trials or relevant literature, the disease term is obsolete, and verapamil's conduction-slowing action could be harmful in bundle branch block. Verapamil also has no currently valid New Zealand authorization.
To proceed, the following is needed:
- Package insert warnings and contraindications (a blocking gap for safety screening)
- Mechanism of action data
- A current, non-obsolete disease definition and clinical rationale for the predicted indication
- Consideration of better-supported candidates among the other predictions, such as hypertensive end-organ disease, with disease-specific clinical data
- Clarification of the regulatory pathway, given all licences are cancelled
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.