Excretion of ketoprofen and nalbuphine in human milk during treatment of maternal pain after delivery

Analgesics are required to prevent and treat postpartum pain, but breast-feeding may be contraindicated, because data on milk transfer are very limited. The present study was undertaken to quantify the transfer of ketoprofen and nalbuphine in milk. Eighteen patients gave their informed consent to participate and completed the study. Following delivery, they received ketoprofen (100 mg/12 hours) and nalbuphine (0.2 mg/kg/4 hours) as an intravenous bolus over 2 to 3 days for postpartum pain. Milk samples were collected during the 12 hours between the third and fourth ketoprofen administrations. Ketoprofen and nalbuphine concentrations were determined with high-performance liquid chromatography. The mean and maximum ketoprofen milk concentrations were 57+/-37 and 91+/-51 ng/mL, respectively. Assuming a milk volume of 150 mL/kg/day, the mean and maximum doses that a breast-fed neonate would ingest during one day are 8.5+/-5.5 and 13.6+/-7.6 microg/kg/day, respectively, and the relative infant dose is 0.31+/-0.17% of the weight-adjusted maternal daily dose. The mean and maximum nalbuphine milk concentrations were 42+/-26 and 61+/-26 ng/mL, respectively. Assuming a milk volume of 150 mL/kg/day, the mean and maximum doses that a breast-fed neonate would ingest during one day is 7.0+/-3.2 and 9.0+/-3.8 microg/kg/day, and the relative infant dose is 0.59+/-0.27% of the weight-adjusted maternal daily dose. Therefore, breast-feeding is permissible when ketoprofen and/or nalbuphine are administered to the mother to treat postpartum pain.