In another case report of a mother taking probenecid along with cephalexin to prolong the half-life of the cephalexin, the baby developed severe diarrhea. The average milk concentration of probenecid and cephalexin was 964 µg/L and 0.745 µg/L, respectively. This corresponds to a relative infant dose of 0.7% for probenecid and 0.5% for cephalexin. The authors concluded that when using this combination of drugs in breast feeding women, clinicians should expect the possibility of adverse GI effects in the infant. Safe in breastfeeding. Watch infant for diarrhea.