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

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.

Alternate Drugs to Consider

Iothalamate Sodium I 125

References

1.

Mountford PJ, Coakley AJ. A review of the secretion of radioactivity in human breast milk: Data, quantitative analysis and recommendations. Nucl Med Commun. 1989;10:15–27. [PubMed: 2645546]

2.

Mattsson S, Johansson L, Leide Svegborn S, et al. 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. [PubMed: 26069086]

3.

Leide-Svegborn S, Ahlgren L, Johansson L, et al. 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. [PubMed: 26732471]

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. [PubMed: 10732169]

6.

Stabin MG, Breitz HB. Breast milk excretion of radiopharmaceuticals: Mechanisms, findings, and radiation dosimetry. J Nucl Med. 2000;41:863–73. [PubMed: 10809203]

7.

Mountford PJ, Coakley AJ. Secretion of radioactivity in breast milk following administration of 123I hippuran. Br J Radiol. 1989;62:388–9. [PubMed: 2713603]

Substance Name

Iodohippurate Sodium I 125

CAS Registry Number

7230-65-1

Drug Class

Breast Feeding

Lactation

Radiopharmaceuticals

Iodine Radioisotopes

Diagnostic Agents