Sodium Iodide I 131 use while Breastfeeding

Drugs containing Sodium Iodide I 131: Iodotope

Sodium Iodide I 131 Levels and Effects while Breastfeeding

Summary of Use during Lactation

Elective diagnostic nuclear medicine procedures should be delayed until the patient is no longer breastfeeding.[1] Information in this record refers to the use of sodium iodide I 131 as a diagnostic and therapeutic agent. Breastfeeding should be discontinued permanently for this child after administration of sodium iodide I 131 in a dose of 0.01 MBq (0.004 mCi) or greater to a nursing mother.[2][3][4][5] Ceasing breastfeeding 6 weeks to 3 months before receiving a therapeutic dose of sodium iodide I 131 is recommended to reduce the radiation dose to the breasts and the risk of milk leakage that can contaminate clothing with radioactive iodine.[5] The American Thyroid Association recommends using I 123 or technetium scans for diagnosis of hyperthyroidism in nursing mothers.[6]

Parents should refrain from close contact with their infants after therapeutic iodine 131 administration. The exact duration depends on the dose administered, condition being treated, and source of the recommendation.[2][3][7] Recommended times range from 15 to 27 days after hyperthyroidism treatment, 16 to 24 days after ablation of thyroid cancer, and 4 to 5 days after follow-up therapy of thyroid ablation therapy.[3]

Drug Levels

I 131 is a beta and high-energy gamma emitter with a main gamma emission energy of 364 keV and a physical half-life of 8.04 days.[2] The effective half-life of sodium iodide I 131 averages 9.2 hours (range 7.3 to 11.1 hours). Iodide is actively secreted into breastmilk and actively taken up by the mother's and infant's thyroid glands. From 25% to 46% of administered radioactivity is excreted into breastmilk after administration of sodium iodide I 131.[8]

Effects in Breastfed Infants

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

Possible Effects on Lactation

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

Alternate Drugs to Consider

(Hyperthyroidism Diagnosis) Sodium Pertechnetate Tc 99m, Sodium Iodide I 123, (Hyperthyroidism Treatment) Propylthiouracil, Methimazole

References

1. Parker JA, Daube-Witherspoon ME, Graham LS, Royal HD, Todd-Pokropek AE, Yester MV. Procedure guideline for general imaging: 3.0. Society of Nuclear Medicine. 2004.

2. Howe DB, Beardsley M, Bakhsh S. Appendix U. Model procedure for release of patients or human research subjects administered radioactive materials. In, NUREG-1556. Consolidated guidance about materials licenses. Program-specific guidance about medical use licenses. Final report. U.S. Nuclear Regulatory Commission Office of Nuclear Material Safety and Safeguards. 2008;9, Rev. 2.

3. Anon. ICRP Publication 94. Release of patients after therapy with unsealed radionuclides. Ann ICRP. 2004;34:v-vi, 1-79. PMID: 15571759

4. Mountford PJ, O'Doherty MJ . Exposure of critical groups to nuclear medicine patients. Appl Radiat Isot. 1999;50:89-111. PMID: 10028630

5. Sisson JC, Freitas J, McDougall IR et al. Radiation safety in the treatment of patients with thyroid diseases by radioiodine 131I : practice recommendations of the American Thyroid Association . Thyroid. 2011;21:335-46. PMID: 21417738

6. Stagnaro-Green A, Abalovich M, Alexander E et al. Guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and postpartum. Thyroid. 2011;21:1081-125. PMID: 21787128

7. Siegel JA, Marcus CS, Stabin MG. Licensee over-reliance on conservatisms in NRC guidance regarding the release of patients treated with 131I. Health Phys. 2007;93:667-77. PMID: 17993847

8. 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. PMID: 2645546

Sodium Iodide I 131 Identification

Substance Name

Sodium Iodide I 131

CAS Registry Number

7790-26-3

Drug Class

Radiopharmaceuticals
Iodine Radioisotopes

Administrative Information

LactMed Record Number

670

Information from the National Library of Medicine's LactMed Database.

Last Revision Date

2011-11-03

Disclaimer

Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.