Ondansetron (Zofran) Safety During Breastfeeding
Ondansetron is considered safe and compatible with breastfeeding according to current anesthesia guidelines, though the FDA label notes that presence in human milk is unknown. 1
Guideline-Based Safety Evidence
The Association of Anaesthetists 2020 guidelines explicitly list ondansetron among safe anti-emetic options for breastfeeding women, alongside granisetron, cyclizine, prochlorperazine, dexamethasone, metoclopramide, and domperidone. 1 This guideline recommendation carries significant weight as it represents expert consensus from a major specialty society addressing perioperative medication use in lactating women.
FDA Labeling Information
The FDA label for ondansetron acknowledges important limitations in available data:
- No human milk data exists - it is not known whether ondansetron is present in human breast milk 2
- Animal data shows milk transfer - ondansetron has been demonstrated in rat milk, suggesting likely human milk presence 2
- The label recommends considering "the developmental and health benefits of breastfeeding along with the mother's clinical need for ondansetron and any potential adverse effects on the breastfed infant" 2
Reconciling Guideline vs. FDA Label
While the FDA label is appropriately cautious given the lack of human pharmacokinetic data, the Association of Anaesthetists guideline represents clinical expert consensus that ondansetron's use is acceptable in breastfeeding women. 1 This guideline was published in 2020 in a high-quality anesthesia journal and specifically addresses perioperative medications including anti-emetics. 1
The practical clinical recommendation is that ondansetron can be used safely during breastfeeding, particularly when needed for nausea and vomiting control. 1
General Principles Supporting Safety
- Most medications transfer into breast milk in small amounts that are generally safe for infants 3, 4
- The dose received via milk is typically much less than known safe doses given directly to infants 4
- Breastfeeding should be encouraged even when mothers require medication, as benefits typically outweigh risks 5, 6
Clinical Approach
- Use ondansetron when clinically indicated for nausea/vomiting in breastfeeding women 1
- No waiting period or pumping-and-dumping is required based on guideline recommendations 1
- Monitor the infant for any unusual symptoms, though adverse effects are not expected 3
- Consider timing doses after breastfeeding sessions when possible to minimize theoretical infant exposure 3