Trimethoprim + Sulfamethoxazole - Safety in breastfeeding mother of preterm infant

[corey]

Hello InfantRisk,

I am a hospital pharmacist - we have a breastfeeding mother of an 8-day-old infant, born at 30+3 weeks. The baby was initially jaundiced and required phototherapy, but bilirubin levels have since returned to normal.

The mother has an ESBL bacteraemia and is being switched to oral trimethoprim + sulfamethoxazole to complete a 14-day course, as this is the only sensitive oral agent. However, her medical team has recommended avoiding breastfeeding and advised her to express milk for the entire 14-day treatment.

My understanding is that concerns around kernicterus and haemolysis in G6PD-deficient infants are based on previous experiences with sulfisoxazole. We typically avoid using trimethoprim + sulfamethoxazole in breastfeeding mothers of term neonates when alternatives are available.

In this particular case, do you agree with the advice to avoid breastfeeding, or could the mother cautiously continue breastfeeding with specific monitoring?

Any guidance you can provide would be greatly appreciated.

Thank you!

[nicholec]

We typically suggest avoiding Bactrim use in premature infants due to the increased risk of hyperbilirubinemia. Due to the infant only being 8 days old and premature, I agree that holding off on breastfeeding is the best option. Thank you for asking questions and seeking to help this mother in conjunction with the medical team. A good clinical pharmacist is invaluable!