Is Buspar (buspirone) safe for a breastfeeding woman to take for anxiety?

Buspirone Safety During Breastfeeding

Buspirone is safe to use during breastfeeding, with exceedingly low transfer into breast milk and a relative infant dose well below the 10% safety threshold, though the FDA label recommends avoiding administration to nursing women when clinically possible.

Evidence for Safety

The most recent and highest quality evidence demonstrates that buspirone poses minimal risk to breastfed infants:

• A 2024 study measuring buspirone levels in human milk found the drug was below the detection level of 1.5 ng/mL in all milk samples from nine mothers taking doses ranging from 7.5 to 30 mg twice daily 1
• The active metabolite 1-PP was detected at low levels, but the calculated relative infant dose (RID) ranged from only 0.21% to 2.17%, which is substantially below the standard 10% threshold for infant safety 1
• No adverse effects were reported in any of the exposed infants 1

FDA Labeling Considerations

The FDA label for buspirone states that "the extent of the excretion in human milk of buspirone or its metabolites is not known" and recommends that "buspirone hydrochloride tablets administration to nursing women should be avoided if clinically possible" 2. However, this conservative recommendation predates the 2024 pharmacokinetic study demonstrating minimal milk transfer.

Clinical Recommendation Algorithm

When treating anxiety in breastfeeding women:

1. First-line options: Consider SSRIs (sertraline or paroxetine preferred) as they have more extensive safety data during lactation 3

2. If buspirone is clinically indicated (e.g., patient preference, SSRI contraindication, or prior response to buspirone):

   • Buspirone can be safely used based on the 2024 evidence showing minimal infant exposure 1
   • Standard adult dosing (15-30 mg/day in divided doses) is appropriate 2

3. Infant monitoring: Watch for any signs of sedation, irritability, or feeding difficulties, though none were observed in the published case series 1

Important Caveats

• Onset of action: Buspirone has a 1-2 week lag time to anxiolytic effect, which may affect patient compliance 4, 5
• Limited long-term data: While the 2024 study provides reassuring short-term safety data, no long-term neurodevelopmental outcomes have been studied 1
• The pharmacokinetic advantage of buspirone is that it was undetectable in milk at all therapeutic doses, making it theoretically safer than many alternatives with measurable milk levels 1