Iodohippurate Sodium I 125 and Breastfeeding

Summary of use during lactation

Information in this record refers to the use of iodohippurate sodium I 125 (ortho-iodohippurate sodium I 125; I 125 OIH) as a kidney function diagnostic agent. International experts recommend nursing the infant just before administration of the radiopharmaceutical and interrupting breastfeeding for 12 to 18 hours after the dose.[1-3] If the mother has expressed and saved milk prior to the examination, she can feed it to the infant during the period of nursing interruption.[1,4,5] Mothers concerned about the level of radioactivity in their milk could ask to have it tested at a nuclear medicine facility at their hospital. When the radioactivity is at a safe level, she may resume breastfeeding. A method for measuring milk radioactivity and determining the time when a mother can safely resume breastfeeding has been published.[6]

Drug levels in milk and infant serum

I 125 is a low-energy pure gamma emitter with a physical half-life of 59.4 days.[2] The effective half-life of I 125 OIH averages 4.8 to 5 hours.[3,6,7] About 2% of an administered dose is excreted into breastmilk.[3]

Effects in breastfed infants

Relevant published information was not found as of the revision date.

Effects on lactation and breastmilk

Relevant published information was not found as of the revision date.

Alternative drugs to consider

Iothalamate Sodium I 125

References

1. MountfordPJ CoakleyAJ A review of the secretion of radioactivity in human breast milk: Data, quantitative analysis and recommendations. Nucl Med Commun 1989 10 15 27 2645546 PubMed
2. MattssonS JohanssonL Leide SvegbornS Radiation dose to patients from radiopharmaceuticals: A compendium of current information related to frequently used substances. ICRP Publication 128. Annex D. Recommendations on breast-feeding interruptions. Ann ICRP 2015 44 2 Suppl 319 21 26069086 PubMed
3. Leide-SvegbornS AhlgrenL JohanssonL Excretion of radionuclides in human breast milk after nuclear medicine examinations. Biokinetic and dosimetric data and recommendations on breastfeeding interruption. Eur J Nucl Med Mol Imaging 2016 43 808 21 26732471 PubMed
4. Early PJ, Sodee DB. Principles and practice of nuclear medicine. 2nd ed. St Louis Mosby-Year Book, Inc 1995:1380-1.
5. ARSAC notes for guidance: Good clinical practice in nuclear medicine. Notes for guidance on the clinical administration of radiopharmaceuticals and use of sealed radioactive sources. 2020. https://www.gov.uk/government/publications/arsac-notes-for-guidance
6. StabinMG BreitzHB Breast milk excretion of radiopharmaceuticals: Mechanisms, findings, and radiation dosimetry. J Nucl Med 2000 41 863 73 10809203 PubMed
7. MountfordPJ CoakleyAJ Secretion of radioactivity in breast milk following administration of 123I hippuran. Br J Radiol 1989 62 388 9 2713603 PubMed