Summary of Use during Lactation

Information in this record refers to the use of iothalamate sodium I 125 as a kidney function diagnostic agent. No information is available on the use of iothalamate sodium I 125 during breastfeeding. However, the biologic half-life of iothalamate after intravenous administration is 1.5 hours with normal kidney function, so the drug will be almost completely eliminated from the body in 8 hours. This time may be longer in patients with impaired kidney function and in patients who receive the drug by subcutaneous injection.[1] 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.[2-4]

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 background levels, they may safely resume breastfeeding. A method for measuring milk radioactivity and determining the time when a mother can safely resume breastfeeding has been published.[5]

Drug Levels

I 125 is a low-energy pure gamma emitter with a physical half-life of 59.4 days.[6]

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

Iodohippurate Sodium I 125

References

1.

Turkel C, Fox A. Hints for successful use of subcutaneous Glofil-125. Nephron. 1998;78:230. [PubMed: 9496747]

2.

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]

3.

Chen MM, Coakley FV, Kaimal A, et al. Guidelines for computed tomography and magnetic resonance imaging use during pregnancy and lactation. Obstet Gynecol. 2008;112:333–40. [PubMed: 18669732]

4.

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]

5.

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

6.

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]

Substance Name

Iothalamate Sodium I 125

CAS Registry Number

17692-74-9

Drug Class

Breast Feeding

Lactation

Radiopharmaceuticals

Iodine Radioisotopes

Diagnostic Agents