If you have any questions about this information, you can contact the Drugs in Breastmilk team through their Facebook page or on druginformation@breastfeedingnetwork.org.uk.
The NHS and MHRA recommend you do not use codeine if you are breastfeeding.Paracetamol and ibuprofen are the recommended first choices for pain relief.If you need opioid pain relief, dihydrocodeine, at the lowest effective dose for the shortest duration possible, is the preferred option. If you have taken some codeine or co-codamol, the risk of adverse effects is low, and you can continue breastfeeding as normal. Switch to a pain relief drug that is compatible with breastfeeding and observe your baby for side effects including breathing problems, drowsiness or poor feeding. This information applies only if your baby was born at full-term and has no breathing difficulties or other health concerns. Seek immediate medical attention if your baby develops side effects. |
In this Factsheet
- Introduction
- Why is codeine not recommended if you are breastfeeding
- Individual differences in codeine metabolism
- What if you have already taken codeine whilst breastfeeding?
- Alternatives to codeine
- Possible side effects
- Caring for your baby and safe sleep when using opioid pain relief
- References
Introduction
It is important that you have access to effective pain relief when you need it while you are breastfeeding. While breastfeeding, your recommended first choices of pain relief are paracetamol or ibuprofen. Stronger medicines are also available which can be used with caution. See our factsheet on pain relief for more detailed information on all available options.
This factsheet covers codeine specifically. It explains why codeine and co-codamol (codeine with paracetamol) are not recommended by the MHRA and NHS if you are breastfeeding, and what to do if you do take some.
Why is codeine not recommended if you are breastfeeding?
In June 2013 the MHRA issued guidance that you should not use codeine if you are breastfeeding. Individuals vary in the way their bodies react to codeine, and there has been concern that in some rare cases this could lead to severe side effects in a breastfed baby. This concern is largely based on a single case study from 2006 (Koren et al., 2006). In this case, researchers concluded that a breastfed baby died from morphine poisoning after his mother took codeine whilst breastfeeding.
However, other researchers have since questioned the validity of this research and suggested that morphine poisoning by breastmilk could not have been the cause of death (Lancet, 2026; Tsuyuki and Pimlott, 2020; Zipursky and Juurlink, 2020). The Lancet, which published the original research, has added an expression of concern to the original paper, and two other journals that also published columns on the case issued a joint retraction in 2020. No other neonatal deaths have been confirmed as being caused by codeine through breastmilk (Zipursky and Juurlink, 2020).
There are reports of breastfed babies experiencing side effects including drowsiness, breathing changes, slow heart rate and changes in skin tone when their mothers were taking codeine. However, in these cases, the infants made a full recovery once their mothers stopped taking codeine (Hale, 2026).
Other sources, including Lactmed, Hale and E-Lactancia, state that codeine can be used with caution in breastfeeding (although it would still not be the first-choice opioid), but this position is not currently endorsed by the MHRA or NHS.
Until/unless the MHRA complete a full review of the evidence and retract the current drug safety warning that is in place in the UK, we cannot support the routine use of codeine while breastfeeding, particularly as there are other preferred options that are compatible with breastfeeding and have more consistent pain relief results. Further information about these alternatives, the differences between them and what to do if you have taken codeine already are discussed below.
Individual differences in codeine metabolism
Codeine is metabolised by the body into different compounds, including morphine. An enzyme called CYP2D6 controls how much codeine is converted to morphine, and CYP2D6 activity varies a lot from person to person, depending on their genetics. People can be classified as ‘poor’, ‘extensive’ or ‘ultra-rapid metabolisers’. Poor metabolisers have very little active CYP2D6 and therefore convert almost no codeine into morphine, which means codeine doesn’t often work well for them. By contrast, ultra-rapid metabolisers convert more codeine into morphine than average, so they may experience significant side effects such as excessive drowsiness and constipation.
The genotype that produces ultra rapid metabolism is rare and can only be identified with genetic testing. People of some ethnic origins are more likely to be ultra-rapid metabolisers than others; it is less common in people of White European origin and is more common in people of North African and Middle-Eastern origin.
The amount of morphine that gets into breastmilk after taking codeine will also vary from person to person. There is therefore concern that in some cases, it could be high enough to cause respiratory depression (slow or shallow breathing, leading to an increase in carbon dioxide levels in the blood) in a breastfed baby, particularly in the first few weeks of life.
What if you have already taken codeine whilst breastfeeding?
If you have already taken some codeine, the risk of side effects in your baby is low, and as long as they were born at full-term and are otherwise healthy you can continue to breastfeed as normal, without the need to pump and dump any milk. Switch to another form of pain relief if possible (see our pain relief factsheet for options compatible with breastfeeding) and monitor your baby closely for any side effects (see the list below). If you have any questions or concerns, you can contact the DiBM team to discuss them.
If you suspect side effects in your baby, seek medical attention immediately.
Alternatives to codeine
If you do need opioid pain relief, SPS recommends dihydrocodeine or tramadol can be used when breastfeeding. This is because the body processes them differently to codeine, and the response is less variable between different people. Dihydrocodeine is available combined with paracetamol to purchase over the counter in pharmacies, or by prescription. Tramadol is available by prescription only. See our factsheet on pain relief for more information.
Possible side effects
With any opioid, side effects are still possible, so you should still take the lowest effective dose for the shortest time possible (no more than 3 days without close medical supervision) and monitor your baby for side effects, including:
- Breathing problems / slower breathing
- Lethargy
- Drowsiness
- Poor Feeding
- Constipation
- Paleness
If you experience any side effects from the drug yourself, it is more likely that your baby will experience side effects too, so they will need careful monitoring. Babies under two months old are at greatest risk of side effects.
If you suspect side effects in your baby, seek medical attention immediately.
Caring for your baby and safe sleep when using opioid pain relief
Opioids may make you feel sleepy, dizzy or confused. Take extra care when looking after your baby if you experience any of these side effects. Medicines that make you drowsy can make bed-sharing less safe. Baby Sleep Info Source (BASIS) has more information on sleep and safety. They recommend that you do not share your bed with your baby after you have taken medication that makes you sleepy.
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References
Click to see references
- Baby sleep information source (Basis): https://www.basisonline.org.uk/
- E-lactancia: codeine. https://e-lactancia.org/breastfeeding/codeine/product/
- Hale, TW. Medications and Mothers Milk. Codeine, updated 11/02/2026.
- Koren G, Cairns J, Chitayat D, Gaedigk A, Leeder SJ. Pharmacogenetics of morphine poisoning in a breastfed neonate of a codeine-prescribed mother. Lancet. 2006;368(9536):704. doi:10.1016/S0140-6736(06)69255-6
- Drugs and Lactation database (Lactmed): https://www.ncbi.nlm.nih.gov/books/NBK501922/
- The Editors of The Lancet. Expression of Concern: Pharmacogenetics of morphine poisoning in a breastfed neonate of a codeine-prescribed mother. The Lancet, 2026; 407659
- MHRA: Codeine for analgesia: restricted use in children because of reports of morphine toxicity https://www.gov.uk/drug-safety-update/codeine-for-analgesia-restricted-use-in-children-because-of-reports-of-morphine-toxicity
- NHS medicines website: https://www.nhs.uk/medicines/co-codamol-for-adults/pregnancy-breastfeeding-and-fertility-while-taking-co-codamol-for-adults/
- Specialist Pharmacy Service information, updated 4th June 2026. Using codeine, dihydrocodeine or tramadol during breastfeeding. https://www.sps.nhs.uk/articles/using-codeine-dihydrocodeine-or-tramadol-during-breastfeeding/
- Tsuyuki RT, Pimlott N. Risks of maternal codeine intake in breast-fed infants: A Joint Statement of Retraction from the Canadian Pharmacists Journal and Canadian Family Physician. Can Pharm J (Ott). 2020;154(1):7-8. Published 2020 Nov 18. doi:10.1177/1715163520970443
- Zipursky J, Juurlink DN. The Implausibility of Neonatal Opioid Toxicity from Breastfeeding. Clin Pharmacol Ther. 2020;108(5):964-970. doi:10.1002/cpt.1882
©The Breastfeeding Network. Version 2.0, published July 2026
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