Is Iobenguane I 123 safe while breastfeeding?

Summary of use during breastfeeding

Information in this record refers to the use of iobenguane I 123 (I 123 meta-iodobenzylguanidine; I 123 MIBG) as a diagnostic agent. The manufacturer recommends that mothers should pump and discard milk for at least 6 days based on the physical half-life of I 123. However, other sources recommend shorter times, depending on the dose (see table). If breastfeeding is discontinued and the mother has expressed and saved milk prior to the examination, she can feed it to the infant during the period of nursing interruption.[1-3] The milk that is pumped by the mother during the time of breastfeeding interruption can either be discarded or stored refrigerated and given to the infant after 10 physical half-lives, or about 5.5 days, have elapsed.

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 a safe level, she may resume breastfeeding. A method for measuring milk radioactivity and determining the time when a mother can safely resume breastfeeding has been published.[4]

Dose | Duration of Interruption 370 MBq (10 mCi) | 48 hours[5] 11 MBq (0.3 mCi) | None[6]

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 123 is a gamma emitter with a photon energy of 159 keV and a physical half-life of 13.1 hours.[6] The maximum effective half-life of I 123 MIBG is 8.56 hours.[3]