Is Iobenguane I 131 safe while breastfeeding?
Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Iobenguane I 131. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Information in this record refers to the use of iobenguane I 131 (I 131 meta-iodobenzylguanidine; I 131 MIBG) as a diagnostic agent. International agencies state that breastfeeding should be interrupted for more than 3 weeks following diagnostic use of I 131 MIBG.[1,2]After therapeutic dosages, the manufacturer recommends that breastfeeding should be withheld for 80 days after the final dose. These times usually result in permanent discontinuation of breastfeeding for this infant, and cessation of breastfeeding for the current infant is recommended by most experts.[3-6] Patients receiving iobenguane I 131usually receive potassium iodide prior to the diagnostic examination to block their thyroid glands’ uptake of the I-131 that is released from the I 131 MIBG. Iodide may interfere with the infant’s thyroid function.
Nursing mothers should not work with substances containing I 131 in their workplace.[7]
Effects on the breastfed infant
Relevant published information was not found as of the revision date.
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
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.[8] Iodide is actively secreted into breastmilk and actively taken up by the mother's and infant's thyroid glands.
Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Iobenguane I 131” (LM805). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.