Summary of Use during Lactation

Information in this record refers to the use of iocanlidic acid I 123 (123I iodophenylpentadecanoic acid; I 123 IPPA) as a diagnostic agent. The International Commission on Radiological Protection states that breastfeeding should be interrupted for more than 3 weeks following diagnostic use of I 123 IPPA. This usually will result in permanent discontinuation of breastfeeding for this infant.[1] However, this time period is based on the presumption that I 123 is contaminated with other iodine isotopes, which is no longer the case.[2] A shorter time might be appropriate. 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.[3]

Drug Levels

I 123 is a gamma emitter with a principal photon energy of 159 keV and a physical half-life of 13.1 hours.[2] Iodide is actively secreted into breastmilk and actively taken up by the mother's and infant's thyroid glands.

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.

References

1.

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]

2.

Dilsizian V, Metter D, Palestro C, Zanzonico P. Advisory Committee on Medical Uses of Isotopes (ACMUI) Sub-Committee on Nursing Mother Guidelines for the Medical Administration of Radioactive Material. Final report submitted: January 31, 2019. 2019. https://www​.nrc.gov/docs​/ML1903/ML19038A498.pdf

3.

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

Substance Name

Iocanlidic Acid I 123

CAS Registry Number

74855-17-7

Drug Class

Breast Feeding

Lactation

Milk, Human

Radiopharmaceuticals

Iodine Radioisotopes

Diagnostic Agents