Iobenguane
Chemical compound
title: "Iobenguane" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["adrenergic-antagonists", "diagnostic-endocrinology", "guanidines", "3-iodophenyl-compounds", "radiopharmaceuticals"] description: "Chemical compound" topic_path: "general/adrenergic-antagonists" source: "https://en.wikipedia.org/wiki/Iobenguane" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Chemical compound ::
::data[format=table title="Infobox drug"]
| Field | Value |
|---|---|
| Verifiedfields | changed |
| Watchedfields | changed |
| verifiedrevid | 459443348 |
| image | Iobenguane.svg |
| image_class | skin-invert-image |
| tradename | Adreview, Azedra |
| DailyMedID | Iobenguane |
| pregnancy_AU | |
| routes_of_administration | Intravenous |
| ATC_prefix | V09 |
| ATC_suffix | IX01 |
| ATC_supplemental | (123I) |
| (131I, diagnostic) | |
| (131I, therapeutic) | |
| legal_AU | |
| legal_BR | |
| legal_CA | |
| legal_DE | |
| legal_NZ | |
| legal_UK | |
| legal_US | Rx-only |
| legal_US_comment | |
| legal_UN | |
| legal_status | Rx-only |
| CAS_number_Ref | |
| CAS_number | 80663-95-2 |
| CAS_number2 | 76924-93-1 |
| CAS_supplemental | 77679-27-7 |
| PubChem | 60860 |
| PubChem2 | 135326 |
| <!-- | PubChem3 |
| --> | DrugBank_Ref |
| DrugBank | DB06704 |
| ChemSpiderID_Ref | |
| ChemSpiderID | 54847 |
| UNII_Ref | |
| UNII | 35MRW7B4AD |
| UNII2 | P2TH1XYZ84 |
| <!-- | UNII3 |
| KEGG | D04559 |
| KEGG2 | D04560 |
| <!-- | KEGG3 |
| ChEBI | 92769 |
| ChEMBL_Ref | |
| ChEMBL | 818 |
| synonyms | meta-iodobenzylguanidine |
| mIBG, MIBG | |
| IUPAC_name | 1-(3-iodobenzyl)guanidine |
| C | 8 |
| SMILES | C1=CC(=CC(=C1)I)CNC(=N)N |
| StdInChI_Ref | |
| StdInChI | 1S/C8H10IN3/c9-7-3-1-2-6(4-7)5-12-8(10)11/h1-4H,5H2,(H4,10,11,12) |
| StdInChIKey_Ref | |
| StdInChIKey | PDWUPXJEEYOOTR-UHFFFAOYSA-N |
| :: |
| Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 459443348 | image = Iobenguane.svg | image_class = skin-invert-image | width = | alt = | caption =
| pronounce = | tradename = Adreview, Azedra | Drugs.com = | MedlinePlus = | DailyMedID = Iobenguane | pregnancy_AU = | pregnancy_AU_comment = | pregnancy_category = | routes_of_administration = Intravenous | ATC_prefix = V09 | ATC_suffix = IX01 | ATC_supplemental = (123I) (131I, diagnostic) (131I, therapeutic)
| legal_AU = | legal_AU_comment = | legal_BR = | legal_BR_comment = | legal_CA = | legal_CA_comment = | legal_DE = | legal_DE_comment = | legal_NZ = | legal_NZ_comment = | legal_UK = | legal_UK_comment = | legal_US = Rx-only | legal_US_comment = | legal_EU = | legal_EU_comment = | legal_UN = | legal_UN_comment = | legal_status = Rx-only
| bioavailability = | protein_bound = | metabolism = | metabolites = | onset = | elimination_half-life = | duration_of_action = | excretion =
| CAS_number_Ref = | CAS_number = 80663-95-2 | CAS_number2 = 76924-93-1 | CAS_supplemental = 77679-27-7 | PubChem = 60860 | PubChem2 = 135326 --| DrugBank_Ref = | DrugBank = DB06704 | ChemSpiderID_Ref = | ChemSpiderID = 54847 | UNII_Ref = | UNII = 35MRW7B4AD | UNII2 = P2TH1XYZ84 | KEGG = D04559 | KEGG2 = D04560 | ChEBI = 92769 | ChEMBL_Ref = | ChEMBL = 818 | NIAID_ChemDB = | PDB_ligand = | synonyms = meta-iodobenzylguanidine mIBG, MIBG
| IUPAC_name = 1-(3-iodobenzyl)guanidine | C=8 | H=10 | I=1 | N=3 | SMILES = C1=CC(=CC(=C1)I)CNC(=N)N | StdInChI_Ref = | StdInChI = 1S/C8H10IN3/c9-7-3-1-2-6(4-7)5-12-8(10)11/h1-4H,5H2,(H4,10,11,12) | StdInChIKey_Ref = | StdInChIKey = PDWUPXJEEYOOTR-UHFFFAOYSA-N | density = | density_notes = | melting_point = | melting_high = | melting_notes = | boiling_point = | boiling_notes = | solubility = | sol_units = | specific_rotation =
Iobenguane, or MIBG, is an aralkylguanidine analog of the adrenergic neurotransmitter norepinephrine (noradrenaline), typically used as a radiopharmaceutical. It acts as a blocking agent for adrenergic neurons. When radiolabeled, it can be used in nuclear medicinal diagnostic and therapy techniques as well as in neuroendocrine chemotherapy treatments.
It localizes to adrenergic tissue and thus can be used to identify the location of tumors such as pheochromocytomas and neuroblastomas. With iodine-131 it can also be used to treat tumor cells that take up and metabolize norepinephrine.
Usage and mechanism
MIBG is absorbed by and accumulated in granules of adrenal medullary chromaffin cells, as well as in pre-synaptic adrenergic neuron granules. The process in which this occurs is closely related to the mechanism employed by norepinephrine and its transporter in vivo. The norepinephrine transporter (NET) functions to provide norepinephrine uptake at the synaptic terminals and adrenal chromaffin cells. MIBG, by bonding to NET, finds its roles in imaging and therapy.
Metabolites and excretion
Less than 10% of the administered MIBG gets metabolized into m-iodohippuric acid (MIHA), and the mechanism for how this metabolite is produced is unknown.
Diagnostic imaging
MIBG scan ::figure[src="https://upload.wikimedia.org/wikipedia/commons/9/90/Pheochromocytoma_Scan.jpg" caption="[[Pheochromocytoma]] seen as dark sphere in center of the body (it is in the left adrenal gland). Image is by MIBG [[scintigraphy]], with [[radiation]] from radioiodine in the MIBG. Two images are seen of the same patient from front and back. Note dark image of the [[thyroid]] due to unwanted uptake of iodide radioiodine from breakdown of the pharmaceutical, by the thyroid gland in the neck. Uptake at the side of the head are from the salivary glands. Radioactivity is also seen in the bladder, from normal renal excretion of iodide."] ::
MIBG concentrates in endocrine tumors, most commonly neuroblastoma, paraganglioma, and pheochromocytoma. It also accumulates in norepinephrine transporters in adrenergic nerves in the heart, lungs, adrenal medulla, salivary glands, liver, and spleen, as well as in tumors that originate in the neural crest. When labelled with iodine-123 it serves as a whole-body, non-invasive scintigraphic screening for germ-line, somatic, benign, and malignant neoplasms originating in the adrenal glands. It can detect both intra and extra-adrenal disease. The imaging is highly sensitive and specific.
Iobenguane concentrates in presynaptic terminals of the heart and other autonomically innervated organs. This enables the possible non-invasive use as an in vivo probe to study these systems.
Alternatives to imaging with 123I-MIBG, for certain indications and under clinical and research use, include the positron-emitting isotope iodine-124, and other radiopharmaceuticals such as 68Ga-DOTA and 18F-FDOPA for positron emission tomography (PET). 123I-MIBG imaging on a gamma camera can offer significantly higher cost-effectiveness and availability compared to PET imaging, and is particularly effective where 131I-MIBG therapy is subsequently planned, due to their directly comparable uptake.
Side effects
Side effects post imaging are rare but can include tachycardia, pallor, vomiting, and abdominal pain.
Radionuclide therapy
MIBG can be radiolabelled with the beta emitting radionuclide 131I for the treatment of certain pheochromocytomas, paragangliomas, carcinoid tumors, neuroblastomas, and medullary thyroid cancer.
Thyroid precautions
Thyroid blockade with (nonradioactive) potassium iodide is indicated for nuclear medicine scintigraphy with iobenguane/mIBG. This competitively inhibits radioiodine uptake, preventing excessive radioiodine levels in the thyroid and minimizing risk of thyroid ablation (in treatment with 131I). The minimal risk of thyroid cancer is also reduced as a result.
The dosing regime for the FDA-approved commercial 123I-MIBG product Adreview is potassium iodide or Lugol's solution containing 100 mg iodide, weight adjusted for children and given an hour before injection. EANM guidelines, endorsed by the SNMMI, suggest a variety of regimes in clinical use, for both children and adults.
Product labeling for diagnostic 131I iobenguane recommends giving potassium iodide one day before injection and continuing five to seven days following. 131I iobenguane used for therapeutic purposes requires a different pre-medication duration, beginning 24–48 hours before iobenguane injection and continuing 10–15 days after injection.
Clinical trials
Iobenguane I 131 for cancers
Iobenguane I 131, marketed under the trade name Azedra, has had a clinical trial as a treatment for malignant, recurrent or unresectable pheochromocytoma and paraganglioma, and the FDA approved it on July 30, 2018. The drug is developed by Progenics Pharmaceuticals.
References
References
- (10 March 2020). "Adreview- iobenguane i-123 injection".
- (8 April 2021). "Azedra- iobenguane i-131 injection, solution".
- (December 2019). "MIBG in neuroblastoma diagnosis and treatment". Seminars in Pediatric Surgery.
- (2007). "Anatomic and functional imaging of metastatic carcinoid tumors". Radiographics.
- (2016). "Imaging in dermatology".
- (2010). "Ashcraft's pediatric surgery". Saunders/Elsevier.
- (January 2018). "Iobenguane". Nucleic Acids Research.
- (2018). "Imaging in Clinical Oncology". Springer.
- (September 2019). "European Association of Nuclear Medicine Practice Guideline/Society of Nuclear Medicine and Molecular Imaging Procedure Standard 2019 for radionuclide imaging of phaeochromocytoma and paraganglioma". European Journal of Nuclear Medicine and Molecular Imaging.
- (December 2020). "Innervation: the missing link for biofabricated tissues and organs". npj Regenerative Medicine.
- (October 1987). "Metaiodobenzylguanidine to map scintigraphically the adrenergic nervous system in man". Journal of Nuclear Medicine.
- (October 2018). "Guidelines on nuclear medicine imaging in neuroblastoma". European Journal of Nuclear Medicine and Molecular Imaging.
- (June 2013). "Comparison of metaiodobenzylguanidine scintigraphy with positron emission tomography in the diagnostic work-up of pheochromocytoma and paraganglioma: a systematic review". The Quarterly Journal of Nuclear Medicine and Molecular Imaging.
- (April 2018). "Current diagnostic imaging of pheochromocytomas and implications for therapeutic strategy". Experimental and Therapeutic Medicine.
- (November 2018). "Theranostic radiopharmaceuticals: established agents in current use". The British Journal of Radiology.
- (May 2008). "EANM procedure guidelines for 131I-meta-iodobenzylguanidine (131I-mIBG) therapy". European Journal of Nuclear Medicine and Molecular Imaging.
- (June 2015). "123I-MIBG Imaging: Patient Preparation and Technologist's Role". Journal of Nuclear Medicine Technology.
- (2008}}{{dead link). "Drug Approval Package: AdreView (Iobenguane I 123) NDA # 022290". [[U.S. Food and Drug Administration]].
- (July 1999). "Iobenguane Sulfate I 131 Injection Diagnostic package insert.". CIS-US, Inc..
- (July 2018). "AZEDRA® (iobenguane I 131". Progenics Pharmaceuticals Inc., a Lantheus company..
- (May 2025). "FDA approves first treatment for rare adrenal tumors". U.S. Food and Drug Administration }}{{dead link.
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