Using nitrofurantoin while breastfeeding a newborn

My patient has a urinary tract infection and is currently breastfeeding. Her son is only 3 weeks old. Is nitrofurantoin a safe antibiotic for treatment?

The use of nitrofurantoin in breastfeeding mothers is generally safe, as only small amounts transfer into the breast milk. Despite the lack of documented reports, there is a risk of hemolytic anemia in all newborns exposed to nitrofurantoin owing to their glutathione instability, especially in infants with glucose-6-phosphate dehydrogenase deficiency. Although some suggest that nitrofurantoin be avoided in infants younger than 1 month, studies have noted that glutathione stability might be established by the eighth day of life. In infants younger than 1 month, an alternative antibiotic might be preferred; however, if an alternative were not available, the use of nitrofurantoin would not be a reason to avoid breastfeeding. In any such case the suckling infant should be monitored by his or her physician.