Is Tositumomab 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 Tositumomab I 131. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Tositumomab I 131 is no longer marketed in the US. Information in this record refers to the use of tositumomab I 131 as a therapeutic agent. No information is available on the use of tositumomab I 131 during breastfeeding. Because of the potential for serious adverse reactions in nursing infants, the manufacturer and expert opinion recommend not administering the drug in women who wish to continue breastfeeding.[1] If the drug is given, breastfeeding should be discontinued. Parents should limit close contact with their infants and small children after therapeutic tositumomab I 131 administration. Suggested contact times by one group are 30 minutes per day or less of contact at a distance of 2 meters or less for a period of 6 to 23 days.[2] Another group suggests avoiding contact with small children at a distance of 10 cm for an average of 8.1 days (range 3.5 to 12.9 days).[3] Additionally, nursing mothers may have excessive I 131 uptake by the breasts, so they should receive potassium iodide or Lugol's solution before receiving tositumomab I 131 to block uptake by the breasts and thyroid.
Nursing mothers should not work with substances containing I 131 in their workplace.[4]
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
After administration of tositumomab I 131, elimination of I 131 is renal. 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.[5]
Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Tositumomab I 131” (LM1141). 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.