Ondansetron is a medication frequently used to manage severe nausea and vomiting. Many breastfeeding parents have concerns about medication safety. This article provides information on ondansetron’s use while breastfeeding, addressing common questions and helping parents make informed choices.
Understanding Ondansetron
Ondansetron, known by the brand name Zofran, is an antiemetic medication. It is primarily prescribed to prevent and treat severe nausea and vomiting that can arise from cancer chemotherapy, radiation therapy, or surgical procedures. The medication works by selectively blocking specific serotonin 5-HT3 receptors found in the gastrointestinal tract and in the brain’s chemoreceptor trigger zone. Serotonin, a natural substance, activates these receptors, triggering the vomiting reflex. By blocking these receptors, ondansetron interrupts this signaling pathway, reducing nausea and preventing vomiting.
Ondansetron Presence in Breast Milk
Ondansetron does transfer into breast milk. Its relatively low molecular weight and moderate plasma protein binding allow for some passage into milk.
Despite this, the amount of ondansetron that reaches breast milk is considered low. Computer models estimate that the quantities present in milk are substantially less than therapeutic doses given directly to infants. One model predicted a median peak milk concentration of 20.2 micrograms per liter after a 4-milligram intravenous dose, translating to a low relative infant dose of approximately 3.3% of the mother’s weight-adjusted dosage.
Potential Effects on Breastfed Infants
Ondansetron is generally considered compatible with breastfeeding. Studies, including those involving postpartum use, have not reported significant adverse effects in breastfed infants exposed to ondansetron. While serious side effects are rare, parents should observe their infant for common symptoms. These can include changes in bowel habits (such as diarrhea or constipation), increased sleepiness, irritability, poor feeding, or reduced wet diapers. Ondansetron is approved for direct use in infants as young as one month of age, further supporting its general safety profile. Although ondansetron can affect heart rhythm in adults by prolonging the QT interval, this concern has not been directly linked to infant exposure through breast milk at typical maternal doses.
Informed Decision-Making for Breastfeeding Parents
Breastfeeding parents considering ondansetron should consult with a healthcare provider before taking the medication. Providers assess factors like the infant’s age and overall health, the specific ondansetron dosage required, and the medication’s medical necessity for the mother’s well-being.
The decision involves weighing the benefits of treating the mother’s condition against any potential, though minimal, risks to the infant. Resources like the Drugs and Lactation Database (LactMed) and the InfantRisk Center provide evidence-based information to assist parents and providers. Healthcare professionals generally advise using the lowest effective dose for the shortest necessary duration for any medication while breastfeeding.