Amiodarone

證據等級: L5

預測適應症: 10 個

Amiodarone: From Ventricular Arrhythmia to Catecholaminergic Polymorphic Ventricular Tachycardia

One-Sentence Summary

Amiodarone is a broad-spectrum Class III antiarrhythmic agent, widely used for the treatment and prevention of life-threatening ventricular and supraventricular arrhythmias. The TxGNN model predicts it may be effective for Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) — a rare inherited arrhythmia syndrome — with no registered clinical trials and 10 publications currently identified in support of this direction.

Quick Overview

Item	Content
Original Indication	No UK marketing authorisation records found in current dataset
Predicted New Indication	Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)
TxGNN Prediction Score	99.78%
Evidence Level	L3 (observational studies and case series only; no dedicated RCT)
UK Market Status	Not marketed
Number of Marketing Authorisations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Amiodarone is a multi-channel antiarrhythmic agent with a uniquely broad pharmacological profile. Its primary mechanism involves blockade of IKr/IKs potassium channels, prolonging the action potential duration (APD) and effective refractory period (ERP). It additionally blocks fast sodium channels (INa) and L-type calcium channels (ICa-L), and exerts non-competitive beta-adrenoceptor blockade — encompassing properties of all four Vaughan-Williams classes simultaneously. Formal mechanism of action data from DrugBank was not available in this evidence pack (a flagged data gap); the above is derived from published pharmacological literature cited within the evidence.

CPVT is a rare inherited ion channelopathy in which mutations in the RYR2 gene (~60% of cases) or CASQ2 gene (~3–5%) cause excessive intracellular calcium release during exercise or adrenergic stimulation. This triggers delayed afterdepolarisations (DADs), which generate triggered activity manifesting as bidirectional or polymorphic ventricular tachycardia. Amiodarone’s ICa-L blockade and non-competitive beta-blockade theoretically suppress this DAD-driven mechanism, offering a plausible pharmacological rationale for the TxGNN model’s prediction.

However, amiodarone’s targeting is notably less precise than flecainide, which directly inhibits the pathological RYR2 calcium release channel via INa blockade and has emerged as the preferred second-line agent in contemporary CPVT management (supported by PMID 22553997). The existing literature consistently positions amiodarone as a third-line adjunct or acute rescue agent — deployed when beta-blockers and flecainide have failed, or to terminate ICD shock storms. No dedicated randomised controlled trial of amiodarone in CPVT has been conducted, and it does not currently feature as a recommended therapy in major CPVT treatment guidelines.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
26513538	2015	Review	Expert Opin Pharmacother	Overview of antiarrhythmic pharmacotherapy for ventricular arrhythmias; reviews amiodarone’s role as an adjunctive option in CPVT when first-line agents fail
35892906	2022	Retrospective Cohort	Life (Basel)	Systematic review of CPVT patients in China; describes clinical characteristics, genetic basis (RYR2/CASQ2), and treatment outcomes including antiarrhythmic drug use
39076628	2022	Retrospective Cohort	Rev Cardiovasc Med	CPVT clinical characteristics, genetic basis, and healthcare resource utilisation from a Chinese cohort; real-world management data across drug classes
22553997	2012	Case Series	Pacing Clin Electrophysiol	Flecainide suppressed ICD-triggered arrhythmic storm in a CPVT patient with a CASQ2 mutation; contextualises amiodarone’s comparatively limited targeted efficacy
37852665	2023	Case Report	BMJ Case Rep	Young child with out-of-hospital cardiac arrest due to refractory VT/VF; amiodarone administered during resuscitation requiring 40 defibrillation shocks before CPVT diagnosis was made
22218697	2012	Case Report	Anesth Analg	Neonate with refractory ventricular arrhythmia (long QT/VT overlap); multimodal pharmacotherapy including amiodarone, esmolol, and lidocaine alongside ventricular pacing described
39735866	2024	Case Report	Front Cardiovasc Med	CPVT in a teenager ultimately resolved only by bilateral cardiac sympathetic denervation after left-sided procedure failed; illustrates treatment-refractory severity when pharmacotherapy is exhausted
30116135	2018	Case Report	Turk Pediatri Arsivi	CPVT presenting as sudden cardiac arrest in a 2-year-old; highlights diagnostic challenges and acute management trajectory in paediatric CPVT
29668588	2018	Case Report	Medicine	Six-year delayed CPVT diagnosis (RYR2 c.7580T>G mutation) in a 9-year-old child; discusses antiarrhythmic management including role of amiodarone
17125720	2006	Case Report	Rev Esp Cardiol	Arrhythmic storm induced by ICD shocks in a CPVT patient; amiodarone used as acute rescue therapy to interrupt the hyperadrenergic cycle

Safety Considerations

Please refer to the SmPC and BNF for safety information. Report suspected adverse reactions via the Yellow Card Scheme.

Conclusion and Next Steps

Decision: Hold

Rationale: Amiodarone’s multi-channel pharmacology offers a mechanistically plausible — but imprecise — rationale for CPVT management. The available evidence consists entirely of case reports and observational cohorts (Evidence Level L3), with no dedicated clinical trials registered and no recognised guideline endorsement for this indication. Amiodarone’s current role in CPVT is limited to third-line or emergency rescue use, where its benefit is largely empirical and overshadowed by flecainide’s more targeted RYR2 inhibition.

To proceed, the following is needed:

Completion of the formal mechanism of action data gap (DrugBank, DG002) to support mechanistic analysis
Retrieval of UK SmPC safety data including warnings, contraindications, and drug interactions (DG001), particularly given amiodarone’s known pulmonary toxicity (1–2%/year), thyroid dysfunction, hepatotoxicity, and CYP2C9/CYP3A4-mediated interactions
Prospective registry or observational data specifically evaluating amiodarone in CPVT patients refractory to beta-blockers and flecainide, to characterise real-world efficacy and tolerability
Paediatric-specific pharmacokinetic and safety assessment, as CPVT predominantly presents in childhood and adolescence (enzyme immaturity, thyroid development susceptibility)
Clarification of UK regulatory status — no MHRA marketing authorisation records were identified in this dataset, which should be verified against the current BNF and MHRA register before any clinical planning
Disclaimer

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