Bexxar and Breastfeeding
It is expected that Bexxar (tositumomab) would pass through breast milk and could cause potentially serious complications in a nursing infant. This medication is linked to a radioactive element that could irreversibly damage the thyroid gland in an infant who consumed the drug through breast milk. Therefore, women who are breastfeeding should not receive Bexxar.
Bexxar® (tositumomab) is a prescription medication used to treat certain types of non-Hodgkin's lymphoma. It is used in people whose cancer has returned, or who have not adequately responded to other treatments. Bexxar is given as an intravenous (IV) infusion on two separate days.
Bexxar is expected to pass through breast milk. It should not be used in breastfeeding women.
Bexxar has not been studied in breastfeeding women. Therefore, it is unknown for certain if the medication passes through breast milk. However, Bexxar is a synthetic (laboratory-made) form of immunoglobulin G (IgG), an antibody made by the immune system. Natural IgG is known to pass through breast milk. Therefore, Bexxar is also expected to pass through breast milk to some extent.
More importantly, one of the components of Bexxar treatment contains Iodine-131, also known as radioiodine. Radioiodine is a radioactive form of iodine that emits radiation. Radioiodine is known to pass through breast milk, which would expose a nursing infant to radiation.
If used while breastfeeding, the radioiodine component of Bexxar could harm a breastfed infant. Radioiodine can damage the thyroid gland and cause hypothyroidism (an underactive thyroid). The effects of radioiodine on the thyroid gland may be irreversible.
To avoid possible harm to a nursing infant, the manufacturer of Bexxar recommends the medication not be used in a breastfeeding woman. If a woman happens to be breastfeeding, she should stop doing so before beginning Bexxar treatment.