A Pharmacologic Study Of Oxycodone In Lactating Mothers After Caesarean Section
Mark Reeves,
Suzette Seaton.
North West Regional Hospital, Burnie, Tasmania
Purpose of Study
Oxycodone has become popular for post-Caesarean section analgesia yet it is not currently recommended for use in breastfeeding mothers due to limited information on its excretion into breast milk. This observational study aimed to investigate the relationship between maternal ingestion of oxycodone after Caesarean section and the resultant maternal plasma, breast milk and neonatal plasma drug levels up to 72 hours postpartum.
Methods
After institutional ethics committee approval, a convenience sample of 50 breastfeeding mothers taking oxycodone had blood and breast milk samples analysed for oxycodone levels at 24 h intervals after Caesarean section. Forty-one neonates had blood samples taken at 48 h.
Results
Oxycodone was detected in the milk of mothers who had taken any dose in a 24 h period, with significant correlation between maternal plasma and milk levels (R2 0.81, see Fig 1). The median milk:plasma (M:P) ratio for the same period was 3.2:1. Over the subsequent 48 hours the relationship between plasma and milk levels was less strong (R2 0.59) and there was a larger range of M:P levels with evidence of persistence of oxycodone in the breastmilk of some mothers. Oxycodone levels up to 168 ng/ml were detected in breast milk (20 % > 100ng/ml). Oxycodone was detected in the plasma of one infant.
Conclusion
Oxycodone is concentrated in human breast milk up to 72 h postpartum. Breastfed infants may receive > 10 percent of a therapeutic infant dose. However, maternal oxycodone intake up to 48 h post Caesarean section probably poses only minimal risk to the breastfeeding infant as low volumes of breast milk are ingested during this period.
Time of Presentation
0830
