Breast milk oxycodone concentrations in mothers given oxycodone for post-Caesarean delivery pain management
Study of women taking controlled-release (CR) oxycodone/naloxone 10/5mg (n = 21) or CR oxycodone 10mg (n = 22) twice daily for 3 days found mean milk-to-plasma ratios were 3.2 & 3.0, respectively. Estimated maximum neonatal plasma concentration was 5.4ng/mL (<10% maternal dose).
Source:
British Journal of Clinical Pharmacology
Resource links:
Specialist Pharmacy Service: Using strong opioid analgesics during breastfeeding
SPS commentary:
The SPS guidance on use of strong opioids for pain during breastfeeding states oxycodone can be used with caution. However, morphine or another appropriate analgesic is preferred, and infant monitoring is required.
The authors note that although oxycodone concentrations are higher in breast milk than maternal plasma, oxycodone clearance is relatively high, therefore the relative infant dose remains in a relatively low range. They conclude that the oxycodone dose received from colostrum and breast milk during the first three postoperative days after Caesarean delivery, with the stated administration schedule, is assumed safe for healthy, term neonates. However, in extreme cases (e.g. high breast milk intake and high maternal oxycodone consumption, lower than usual clearance in the neonate) it is possible for the neonate to receive a dose through breast milk that may elicit opioid effects.
Although noroxycodone concentrations in breast milk were 3-fold higher compared to maternal plasma, and in breast milk the average noroxycodone/oxycodone ratio was 2, the clinical relevance of this finding is likely minor, as noroxycodone has only a weak μ-opioid receptor activity. Also consistent with previous findings, the active metabolite oxymorphone plasma concentrations were very low (≤0.9 ng/mL).