Technetium Tc 99m Medronate

Drug Levels and Effects:

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 oftechnetiumTc99mmedronate (</span>Tc99mmethylene diphosphonate;Tc99mMDP) as a diagnostic agent. The United States Nuclear Regulatory Commission states that breastfeeding need not be interrupted after administration ofTc99mMDP in doses up to 1000 MBq (30 mCi) to a nursing mother.[2] However, to follow the principle of keeping exposure "as low as reasonably achievable", some experts recommend nursing the infant just before administration of the radiopharmaceutical and interrupting breastfeeding for 3 to 6 hours after the dose, then expressing the milk completely once and discarding it. 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.[3][4][5] Mothers need not refrain from close contact with their infants after usual clinical doses.[6]

Mothers concerned about the level of radioactivity in their milk could ask to have it tested at a nuclear medicine facility at their hospital and 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.[7]

Drug Levels:

Tc99mis a gamma emitter with a principal photon energy of 140.5 keV and a physical half-life of 6.024 hours.[2] The effective half-life ofTc99mMDP averages 4.3 hours (range 3.5 to 5.1 hours).[3][7]

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:



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. 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
4. Early PJ, Sodee DB. Principles and practice of nuclear medicine. 2nd ed. St. Louis. Mosby-Year Book, Inc. 1995:1380-1.
5. Administration of Radioactive Substances Advisory Committee. Notes for guidance on the clinical administration of radiopharmaceuticals and use of sealed radioactive sources. 2006;25-7.
6. Mountford PJ, O'Doherty MJ . Exposure of critical groups to nuclear medicine patients. Appl Radiat Isot. 1999;50:89-111. PMID:10028630
7. Stabin MG, Breitz HB. Breast milk excretion of radiopharmaceuticals: mechanisms, findings, and radiation dosimetry. J Nucl Med. 2000;41:863-73. PMID:10809203

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Radiopharmaceuticals

  • Technetium
  • Compounds

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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