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

Buspar (Buspirone) Safety During Breastfeeding

Buspirone is safe for breastfeeding mothers, with exceedingly low transfer into breast milk and a relative infant dose well below the 10% safety threshold, posing minimal risk to the breastfed infant.

Evidence for Safety

The most recent and highest quality evidence comes from a 2024 study that directly measured buspirone and its active metabolite (1-PP) in human milk 1. This study provides the strongest data available:

• Buspirone was undetectable (below 1.5 ng/mL) in all milk samples from mothers taking 7.5 to 30 mg twice daily 1
• The relative infant dose (RID) ranged from 0.21% to 2.17%, which is far below the standard 10% safety threshold for infant exposure 1
• No adverse effects were reported in any of the exposed infants 1
• Only low levels of the active metabolite 1-PP were detected, even at the highest maternal doses 1

Clinical Implications

Breastfeeding can continue without interruption while taking buspirone at standard therapeutic doses. The FDA label for buspirone states that mothers should "inform your physician if you are breast feeding an infant" 2, but this is a general precautionary statement rather than a contraindication, and the recent evidence strongly supports safety.

Key Points for Clinical Practice:

• No need to pump and dump or interrupt breastfeeding when taking buspirone 1
• Standard dosing regimens (7.5-30 mg twice daily) result in clinically insignificant infant exposure 1
• Infant monitoring is not specifically required beyond routine well-child care, given the minimal transfer and absence of reported adverse effects 1

Comparison to Other Anxiolytics

While the provided evidence focuses primarily on buspirone, it's worth noting that benzodiazepines have different safety profiles during lactation:

• Midazolam has low systemic bioavailability after oral doses due to first-pass metabolism, making infant exposure low 3
• Diazepam transfers into breast milk in significant levels and has an active metabolite with prolonged half-life, making it less ideal for regular use 3

Buspirone's safety profile during breastfeeding is superior to many benzodiazepines due to its minimal milk transfer and lack of sedative effects in exposed infants 1.

General Principles for Medication Safety During Lactation

The broader literature emphasizes that most medications are compatible with breastfeeding when properly evaluated 4, 5. The key factors to consider include:

• Pharmacokinetic properties of the drug (molecular weight, protein binding, lipid solubility) 5, 6
• Relative infant dose below 10% is generally considered safe 1
• Benefits of continued breastfeeding typically outweigh theoretical medication risks 4, 7