The evidence relating to the safe use of opioid analgesics in breastfeeding mothers is very variable between individual drugs.
This group of drugs presents a complex picture of different indications (mild to moderate pain, moderate to severe pain, palliative care only, obstetric pain, non-cancer pain etc) and administration routes (oral, sublingual, transdermal, intravenous, intramuscular, subcutaneous, epidural, intrathecal). Therefore, a recommendation for an equivalent alternative opioid is not always possible and the choice of drug may have to be made on the individual clinical situation.
Morphine is considered to be the benchmark for the treatment of severe pain in breastfeeding mothers.
However, the use of any opioid should be at the lowest effective dose and only short-term. A non-opioid analgesic should be used whenever possible.
Infants exposed to opioids in utero or for longer periods while breastfeeding should be observed for withdrawal symptoms on sudden discontinuation of maternal use or breastfeeding.
Monitor infants for drowsiness, adequate weight gain, respiratory problems and developmental milestones, especially in younger (up to one month), exclusively breastfed infants.
Acting Co-Director, West Midlands Medicines Information Service & UK Drugs in Lactation Advisory Service