You technically can take Buspar (buspirone) while breastfeeding, but there are quite a few considerations to take into account.
While there's limited information, the research1 we do have indicates that maternal doses of buspirone up to 45 mg daily produce low levels in milk. However, because long-term effects of buspirone during breastfeeding aren’t yet fully understood, a different medication might be a safer bet, especially when nursing a newborn or preterm infant.
Though one study showed that Buspar was undetectable in both breastmilk and an infant's serum when the mother was taking 15 mg three times daily, there was one reported case of possible drug-induced seizure-like activity and cyanosis in a 3-week-old. This was potentially due to a combination of medications the mother was taking, which included Buspar, fluoxetine and carbamazepine.
Ultimately, as with any medication, it's essential to discuss the pros and cons with your healthcare provider.