Codeine Should NOT Be Prescribed to Breastfeeding Mothers
Breastfeeding women should not take codeine due to the unpredictable risk of severe neonatal depression and death in infants, and safer alternative analgesics are readily available. 1
Critical Safety Concerns with Codeine
Genetic Variability Creates Unpredictable Risk
Codeine is a prodrug that requires metabolism by the CYP2D6 enzyme to convert to its active form, morphine. 1
Genetic polymorphism in CYP2D6 creates dangerous variability: Women who are ultrarapid metabolizers produce much higher concentrations of morphine in breast milk, which in extreme cases has led to severe neonatal depression and death in infants. 1
The inability to predict which infants may be sensitive makes codeine particularly dangerous, as you cannot identify at-risk mother-infant pairs before harm occurs. 1
Ethnic Variations in Risk
Ultrarapid metabolizers comprise up to 28% of Middle Eastern and Northern African populations, up to 10% of Caucasian populations, and up to 1% of Asian populations. 1
Poor metabolizers (who get little analgesic benefit) represent 5-10% of European Caucasians but are less common in Asians. 1
Additional Transfer Concerns
- Codeine is secreted in breast milk due to high lipophilicity and weak protein binding, with potential for further metabolism by the infant. 1
Regulatory Position
International Consensus Against Use
The US FDA and European Medicines Agency advise that breastfeeding women should not take codeine. 1
While the UK MHRA suggests codeine taken in moderation for short duration may be suitable for most women, the guideline explicitly states: "Because there are other alternative weak opioid analgesics, we recommend that breastfeeding women should not take codeine unless the regulatory advice is modified." 1
Safer Alternatives
First-Line Opioid Choice
Morphine is recommended as the opioid of choice if strong analgesia is required in breastfeeding women. 1
Morphine transfers to breast milk in small amounts, and studies following caesarean section showed low transfer with no neurodevelopmental delays in breastfed babies. 1
If repeated morphine doses are used, monitor the infant for signs of sedation and respiratory depression. 1
Preferred Weak Opioid Alternative
Dihydrocodeine may be the preferred weak opioid for postoperative use in breastfeeding women due to cleaner metabolism compared with codeine. 1
Unlike codeine, dihydrocodeine's analgesic effect comes from the parent compound rather than requiring CYP2D6 metabolism, making it more predictable. 1
Non-Opioid Options
Paracetamol (acetaminophen) is safe, with infant exposure via breast milk significantly less than pediatric therapeutic doses. 1
Ibuprofen has been used extensively for postpartum pain and is considered safe during breastfeeding. 1
NSAIDs including diclofenac, naproxen, celecoxib, and ketorolac are all compatible with breastfeeding. 1
If Codeine Has Already Been Taken
- Discarding breast milk for 15 hours should allow full clearance from maternal plasma and insignificant transfer to breast milk thereafter. 1
Clinical Bottom Line
The prescription of "Terpin codeine twice daily" to a breastfeeding mother is not recommended given the documented cases of infant mortality, unpredictable genetic variability, and availability of safer alternatives. Switch to morphine for strong pain, dihydrocodeine for moderate pain, or non-opioid analgesics (paracetamol, ibuprofen) for mild-to-moderate pain. 1