Fluoride Action Network

Drug Levels and Effects

Information in this record refers to the use of sodium fluoride F 18 as a diagnostic agent. The manufacturer recommends withholding breastfeeding for 24 hours after a diagnostic dose of 300-450 MBq (8 to 12 mCi); however, this time might be longer than necessary given the minimal amount of fluoride that appears in breastmilk. Twenty-four hours is about 10 half-lives of fluoride F 18 and less than 0.01% of the radioactivity administered will remain in the body. The mother can nurse just before administration of the radiopharmaceutical. 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][2][3]

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.[4]

Drug Levels

Fluoride F18 decays by positron emission with a physical half-life of 109.7 minutes.

Maternal Levels. A study in one mother who received an oral dose of 25 mg of nonradioactive sodium fluoride found that milk fluoride concentrations closely paralleled maternal serum fluoride concentration at 21 to 32% of maternal serum levels over an 8-hour period. The authors estimated that this represents only 0.2% of the dose given to the mother.[5]

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

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.


1 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/

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]

3 Early PJ, Sodee DB. Principles and practice of nuclear medicine. 2nd ed. St. Louis. Mosby-Year Book, Inc. 1995:1380-1.

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

5 Ekstrand J, Spak CJ, Falch J et al. Distribution of fluoride to human breast milk following intake of high doses of fluoride. Caries Res. 1984;18:93-5. [PubMed]

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Substance Identification

Substance Name: Sodium Fluoride F 18

CAS Registry Number: 22554-99-0

Drug Class:

  • Radiopharmaceuticals
  • Fluoride Radioisotopes


Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-. Sodium Fluoride F 18. [Updated 2014 Nov 7].

*Available online at: https://www.ncbi.nlm.nih.gov/books/NBK500705/