Ondansetron (Zofran) and Breastfeeding
Ondansetron is safe and compatible with breastfeeding and can be used when clinically indicated for nausea and vomiting without requiring any waiting period or pumping-and-dumping. 1, 2
Guideline-Based Recommendations
The Association of Anaesthetists 2020 guidelines explicitly recommend ondansetron as a safe anti-emetic option for breastfeeding women, based on expert consensus from this major specialty society. 1, 2 While there are no published studies on transfer into human milk (only animal data exists), the clinical recommendation supports its use without restrictions. 1
No interruption of breastfeeding is necessary after ondansetron administration. 2 Women can continue nursing immediately after taking the medication without any delay or need to discard breast milk. 2
FDA Labeling Information
The FDA label acknowledges uncertainty, stating "it is not known whether ondansetron is present in human milk" and notes that ondansetron is present in rat milk. 3 The label recommends considering "the developmental and health benefits of breastfeeding along with the mother's clinical need for ondansetron tablets and any potential adverse effects on the breastfed infant." 3 However, this cautious regulatory language should be interpreted in the context of the more definitive guideline recommendations from specialty societies. 1, 2
Clinical Approach
- Use ondansetron when clinically indicated for nausea and vomiting in breastfeeding women without hesitation. 1, 2
- Reassure mothers that current anesthesia guidelines support its safety profile during lactation. 1, 2
- No special precautions such as timing feeds around doses or discarding milk are required. 2
Important Context
The lack of human milk transfer data does not equate to risk—many medications used safely during breastfeeding have limited pharmacokinetic data. 4 The guideline recommendation reflects the clinical consensus that ondansetron's properties (likely minimal transfer if any, poor oral bioavailability if transferred) make it compatible with breastfeeding. 1, 2
Common pitfall to avoid: Do not unnecessarily discourage breastfeeding or recommend pumping-and-dumping based solely on the absence of human milk data when authoritative guidelines explicitly support its use. 1, 2