Iobenguane
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| Clinical data | |
|---|---|
| Other names | meta-iodobenzylguanidine mIBG, MIBG |
| Routes of administration | Intravenous |
| ATC code | |
| Identifiers | |
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| CAS Number | |
| PubChem CID | |
| CompTox Dashboard (EPA) | |
| Chemical and physical data | |
| Formula | C8H10IN3 |
| Molar mass | 275.09 g/mol g·mol−1 |
Iobenguane, also known as metaiodobenzylguanidine or mIBG, or MIBG (tradename Adreview) is a radiopharmaceutical.[1] It is a radiolabeled molecule similar to noradrenaline.
The radioisotope of iodine used for the label can be iodine-123 (for imaging purposes only) or iodine-131 (which must be used when tissue destruction is desired, but is sometimes used for imaging also).
It localizes to adrenergic tissue and thus can be used to identify the location of tumors[2] such as phaeochromocytomas and neuroblastomas. With I-131 it can also be used to eradicate tumor cells that take up and metabolize norepinephrine.
Thyroid precautions and use with potassium iodide
Thyroid blockade with (nonradioactive) potassium iodide is indicated for nuclear medicine scintigraphy with iobenguane/mIBG. This prevents radioiodine from the pharmaceutical from being metabolized to free iodide, then absorbed by thyroid, where (especially in the case of I-131) it represents a thryoid carcinogenic hazard.
The FDA-approved dosing of potassium iodide for this purpose are as follows: infants less than 1 month old, 16mg; children 1 month to 3 years, 32 mg; children 3 years to 18 years, 65mg; adults 130mg[3]. However, some sources recommend alternative dosing regimens[4].
Not all sources are in agreement on the necessary duration of thyroid blockade, although agreement appears to have been reached about the necessity of blockade for both scintigraphic and therapeutic applications of iobenguane. Commercially available iobenguane is labeled with iodine-123, and product labeling recommends administration of potassium iodide 1 hour prior to administration of the radiopharmaceutical for all age groups [5], while the European Associated of Nuclear Medicine recommends (for iobenguane labeled with either I-131 or I-123,) that potassium iodide administration begin one day prior to radiopharmaceutical administration, and continue until the day following the injection, with the exception of new-borns, who do not require potassium iodide doses following radiopharmaceutical injection[6].
Product labeling for diagnostic iodine-131 iobenguane recommends potassium iodide administration one day before injection and continuing 5 to 7 days following[7]. Iodine-131 iobenguane used for therapeutic purposes requires a different pre-medication duration, beginning 24-48 hours prior to iobenguane injection and continuing 10-15 days following injection[8].
References
- ^ "Iobenguane I 131 Sulfate (Intravenous Route) - MayoClinic.com". Retrieved 2007-12-15.
- ^ Scarsbrook AF, Ganeshan A, Statham J; et al. (2007). "Anatomic and functional imaging of metastatic carcinoid tumors". Radiographics. 27 (2): 455–77. doi:10.1148/rg.272065058. PMID 17374863.
{{cite journal}}: Explicit use of et al. in:|author=(help)CS1 maint: multiple names: authors list (link) - ^ Kowalsky RJ, Falen, SW. Radiopharmaceuticals in Nuclear Pharmacy and Nuclear Medicine. 2nd ed. Washington DC: American Pharmacists Association; 2004.
- ^ https://www.eanm.org/scientific_info/guidelines/gl_paed_mibg.pdf?PHPSESSID=46d05b62d235c36a12166bf939b656c7
- ^ http://nuclearpharmacy.uams.edu/resources/adreview.pdf
- ^ https://www.eanm.org/scientific_info/guidelines/gl_paed_mibg.pdf?PHPSESSID=46d05b62d235c36a12166bf939b656c7
- ^ Iobenguane Sulfate I 131 Injection Diagnostic package insert. Bedford, MA: CIS-US, Inc. July 1999.
- ^ https://www.eanm.org/scientific_info/guidelines/gl_radio_ther_benzyl.pdf?PHPSESSID=46d05b62d235c36a12166bf939b656c7
External links
- Iodine 131-metaiodobenzylguanidine at the NCI Drug Dictionary
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