# Iobenguane I-123 (cardiac use)

Source: https://nuclide.cc/drugs/i-123-mibg-cardiac/  
Nuclide record `i-123-mibg-cardiac` (Agent). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

A radioactive tracer that mimics the body's own "fight or flight" nerve chemical and is taken up by the nerve endings in heart muscle. In people with heart failure, comparing how much of it the heart holds onto against the surrounding chest tissue gives a read on how damaged the heart's nerve supply is, which relates to future risk.

## Summary

AdreView (iobenguane I-123 injection) is a noradrenaline-analogue SPECT agent originally approved by the FDA in 2008 for detecting primary or metastatic phaeochromocytoma or neuroblastoma; a 2013 supplemental approval added a distinct cardiac indication (outside this record's oncology scope but the reason it is filed here as a cardiac agent): scintigraphic assessment of sympathetic innervation of the myocardium by measurement of the heart-to-mediastinum (H/M) uptake ratio in patients with NYHA class II or III heart failure and left ventricular ejection fraction 35% or less.

In this population, AdreView is labelled to help identify patients with lower one- and two-year mortality risk, indicated by an H/M ratio of 1.6 or greater (expected range 1.0-2.4); the label explicitly states its utility has not been established for selecting a therapeutic intervention, for monitoring response to therapy, or for identifying patients at high risk of death. The recommended adult dose is 10 mCi (370 MBq) by slow intravenous injection, with thyroid blockade (potassium iodide or perchlorate) beforehand to protect the thyroid from free iodine-123, and planar chest imaging beginning about 4 hours after injection, with optional SPECT.

This is a different mechanism and a different clinical question from the perfusion tracers in this file: it does not assess coronary blood flow or ischaemia, but the integrity of the heart's autonomic nerve supply, used as a risk-stratification adjunct in systolic heart failure rather than a coronary artery disease diagnostic.

## Fields

- Kind: Agent
- Last checked: 2026-09-22
- Also known as: I-123 MIBG; 123I-mIBG
- Tags: SPECT; sympathetic innervation; heart failure
- Brand: AdreView
- Modality: SPECT tracer
- Mechanism: Iobenguane (metaiodobenzylguanidine, MIBG) is a noradrenaline analogue taken up by cardiac sympathetic nerve terminals through the same norepinephrine transporter (uptake-1) used by noradrenaline itself, then stored in neurosecretory vesicles. In failing hearts, sympathetic nerve terminals are damaged or down-regulated, reducing MIBG uptake and washout characteristics; the heart-to-mediastinum (H/M) uptake ratio on a planar image taken about 4 hours after injection quantifies how much sympathetic innervation remains, independent of coronary anatomy.
- Approvals: US 2008: Detection of primary or metastatic pheochromocytoma or neuroblastoma as an adjunct to other diagnostic tests; US 2013: Scintigraphic assessment of sympathetic innervation of the myocardium via heart-to-mediastinum ratio in NYHA class II-III heart failure with LVEF ≤ 35%, to help identify patients with lower 1- and 2-year mortality risk
- Dosing: Slow intravenous injection over 1-2 minutes, after thyroid blockade; 10 mCi (370 MBq) for patients 16 years or older (or under 16 and ≥ 70 kg); weight-scaled dose for younger/lighter paediatric patients; planar chest imaging at about 4 hours post-injection, SPECT optional

## Sources

- FDA label: AdreView (iobenguane I 123 injection), 2020 revision: https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/022290s005lbl.pdf
- FDA approval letter: supplemental NDA 22-290/S-001 (cardiac heart failure indication, 2013): https://www.accessdata.fda.gov/drugsatfda_docs/appletter/2013/022290orig1s001ltr.pdf

## Connected records

- drugs: [131I-MIBG (iobenguane I-131) therapy](https://nuclide.cc/drugs/i131-mibg/), [Iobenguane I-131 (therapeutic)](https://nuclide.cc/drugs/iobenguane-i-131/)
- technologies: [MIBG imaging and 131I-MIBG therapy](https://nuclide.cc/technologies/mibg-theranostics/)
- isotopes: [Iodine-123](https://nuclide.cc/isotopes/i-123/)
- companies: [PDRadiopharma](https://nuclide.cc/companies/pdradiopharma/)

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