The Basics
What is Sodium Iodide I 131?
Used to treat hyperthyroidism and some cases of thyroid cancer.
Brand names for Sodium Iodide I 131
Sodium Iodide I 131
How Sodium Iodide I 131 is classified
Radiopharmaceuticals, Iodine Radioisotopes
Sodium Iodide I 131 During Pregnancy
Sodium Iodide I 131 pregnancy category
Category XNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.
What we know about taking Sodium Iodide I 131 while pregnant
N/A
Taking Sodium Iodide I 131 While Breastfeeding
What are recommendations for lactation if you're taking Sodium Iodide I 131?
Information in this record refers to the use of sodium iodide I 131 as a diagnostic and therapeutic agent. The use of I 131 is contraindicated during lactation.[1] 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][6][7][8][9] Ceasing breastfeeding at least 4 weeks 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.[4][10][11] The American Thyroid Association recommends using I 123 or Tc99m pertechnetate scans for diagnosis of hyperthyroidism in nursing mothers.[1] 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][12][13] 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.[13] Nursing mothers should not work with substances containing I 131 in their workplace.[14]
Maternal / infant drug levels
Information in this record refers to the use of sodium iodide I 131 as a diagnostic and therapeutic agent. The use of I 131 is contraindicated during lactation.[1] 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][6][7][8][9] Ceasing breastfeeding at least 4 weeks 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.[4][10][11] The American Thyroid Association recommends using I 123 or Tc99m pertechnetate scans for diagnosis of hyperthyroidism in nursing mothers.[1] 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][12][13] 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.[13] Nursing mothers should not work with substances containing I 131 in their workplace.[14]
Possible effects of Sodium Iodide I 131 on milk supply
Relevant published information was not found as of the revision date.
Possible alternatives to Sodium Iodide I 131
(Hyperthyroidism Diagnosis) Sodium Pertechnetate Tc 99m, Sodium Iodide I 123; (Hyperthyroidism Treatment) Propylthiouracil, Methimazole.
List of References
Lactation sources: Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK501922/1. Alexander EK, Pearce EN, Brent GA et al. 2016 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease during Pregnancy and the Postpartum. Thyroid. 2017;27:315-89. PMID: 28056690
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. http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1556/v9/r2/
3. Mountford PJ, O’Doherty MJ. Exposure of critical groups to nuclear medicine patients. Appl Radiat Isot. 1999;50:89-111. PMID: 10028630
4. 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
5. Silberstein EB, Alavi A, Balon HR et al. The SNMMI practice guideline for therapy of thyroid disease with 131I 3.0. J Nucl Med. 2012;53:1633-51. PMID: 22787108
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. Annex D. Recommendations on breast-feeding interruptions. Ann ICRP. 2015;44 (2 Suppl):319-21. PMID: 26069086
7. International Atomic Energy Agency. Radiation Protection and Safety in Medical Uses of Ionizing Radiation, IAEA Safety Standards Series No. SSG-46, IAEA, Vienna. 2018. https://www.iaea.org/publications/11102/radiation-protection-and-safety-in-medical-uses-of-ionizing-radiation
8. National Radiation Protection Board (UK). Administration of radioactive substances advisory committee. Notes for guidance on the clinical administration of radiopharmaceuticals and use of sealed radioactive sources. 2019. https://assets.publishing.service.gov.uk/government/…/file/…/ARSAC_NfG_2019.pdf
9. Mitchell KB, Fleming MM, Anderson PO et al. ABM Clinical Protocol #30: Radiology and Nuclear Medicine Studies in Lactating Women. Breastfeed Med. 2019;14:290-4. PMID: 31107104
10. Balon HR, Silberstein EB, Meier DA et al. Society of Nuclear Medicine Procedure Guideline for Thyroid Uptake Measurement, Version 3.0. 2006. http://snmmi.files.cms-plus.com/docs/Thyroid%20Uptake%20Measure%20v3%200.pdf
11. De Groot L, Abalovich M, Alexander EK et al. Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2012;97:2543-65. PMID: 22869843
12. 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
13. Anon. ICRP Publication 94. Release of patients after therapy with unsealed radionuclides. Ann ICRP. 2004;34:v-vi, 1-79. PMID: 15571759
14. Almen A, Mattsson S. Radiological protection of foetuses and breast-fed children of occupationally exposed women in nuclear medicine – Challenges for hospitals. Phys Med. 2017;43:172-7. PMID: 28882410
15. 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
16. 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. PMID: 26732471
Disclaimer: This material is provided for educational purposes only and is not intended for medical advice, diagnosis, or treatment. Consult your healthcare provider with any questions.
