Opioid analgesia for breastfeeding mothers

The benefits of breastfeeding are well known, and everything possible should be done to encourage it.1 Pain control in mothers after delivery, and in particular after caesarean section, follows a standard pain ladder approach—although the evidence base is weak for efficacy of common analgesics.23

Weak opioids such as codeine had been used for many years to manage postpartum pain. Practice changed dramatically, however, after one high profile case of an infant’s death in association with a codeine-paracetamol product in 2006, allegedly from over-expression of the enzyme P450 2D6 (CYP2D6) in the neonate, metabolising codeine ingested through breast milk to excess morphine.45 As codeine and paracetamol concentrations were unexpectedly high in the infant post mortem, reports of the case were eventually discredited and have now been retracted.67 But concern about opioids in breast milk persists among drug regulators.8

Occasional reports of drowsiness in breastfed infants associated with maternal codeine are still published, leaving mothers and their clinicians with important questions …