Advising on medicines during breastfeeding

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Most medicines can be used throughout breastfeeding, in some cases further risk-reducing methods may be required

Developing your advice

Once you have completed a risk assessment of the medicine(s) in breastfeeding, you are ready to provide advice. The overall aim should be to allow the mother to continue breastfeeding where possible, whilst taking the most appropriate treatment.

In the majority of cases this will be possible, particularly if you have based your risk assessment on the advice we provide. However in some cases, where medicines cannot be continued as normal whilst breastfeeding, you may need to suggest different options.

Minimising side-effects in the infant

Risks to the infant should be reduced whilst protecting the breastfeeding relationship.

Simplify the mother’s medication

Avoid unnecessary medicine use, including self-medication.

In general, the less medicines a mother is taking, the less risk to the infant. If a mother is taking medicines during pregnancy, review these before delivery and consider whether the medicine could be stopped, or if non-medicinal options could be used instead.

Offer alternatives

In some cases, an alternative medicine or formulation may be safer or have more evidence for its use. This could include changes to the route of administration.

A good example of this would be for the treatment of hayfever where nasal or ocular preparations may be an option over oral antihistamines.

Remember, when considering alternatives to recommend, it is just as important to ensure they are suitable for the mother’s clinical condition in addition to their suitability in breastfeeding.

Medicine factors to consider

Neonates (and particularly premature infants) are at greater risk from exposure to medicines via breast milk, because of immature excretory functions and the consequent risk of medicine accumulation.

The following factors should be taken into consideration when thinking about the choice of medicine:

  • Medicines with a long half-life can increase the risk of accumulation in the infant and therefore increase the risk of adverse effects.
  • Multiple medication regimens may pose an increased risk especially when adverse effects such as drowsiness are additive.
  • Avoid new medicines if a therapeutically equivalent alternative that has been more widely used is available.
  • Avoid use of medicines known to cause serious toxicity in adults or children.
  • Medicines licensed for use in infants do not generally pose a hazard.

Timing of feeds

Seek further advice from our Medicines Advice service or Breastfeeding Medicines Advice service service (UKDILAS) before suggesting either of the following approaches to reduce infant exposure:

  • give the mother’s dose immediately after the infant has been fed with the aim of avoiding feeding at peak milk concentrations; or
  • withhold breastfeeding until after a suitable washout period of the medicine. This is most appropriate for short courses of a hazardous medicine.

Both options rely on knowledge of pharmacokinetic data, which may be unreliable or not readily available. In addition they are often impractical for the mother, especially where young infants are feeding frequently up to 2 hourly.

Monitoring the infant

It’s always important to give advice on what to look out for in the infant to indicate if they’re experiencing an effect from the medicine through breastmilk. However, it can be difficult to identify adverse effects in a very young infant.

The following can be helpful:

  • Advise that infant side-effects are rare. Monitoring is usually used as a precaution.
  • Younger, exclusively breastfed infants are at greater risk of getting side-effects. Premature infants are also at greater risk, as are those exposed to multiple medicines.
  • Think about who are you advising. For example, a parent won’t be able to monitor for hypotension, but you could liaise with the GP or health visitor.
  • Give practical tips. For example, rather than telling the mother to monitor for drowsiness, advise her to make sure the infant is waking up to feed, or isn’t sleeping for longer, or more often, than expected.
  • Give general advice to make sure the infant is feeding well, putting on weight, not irritable, achieving milestones, etc. This will quickly detect any potential issues. Usually, further investigation is required before attributing any side-effects to the medicine.

You can find information on what to monitor for individual medicines by searching our medicines specific advice during breastfeeding.


Include all those involved with caring for the infant in the discussion, for example the partner or other members of the family. You may need to liaise with the health visitor, midwife, GP or others involved in their care and it is important to explain to the mother and/ or partner the reasons for this.

Expert advice

Seek further advice from our Medicines Advice service or Breastfeeding Medicines Advice service service (UKDILAS), our specialist advisory service, if there is any doubt about the safety of a medicine or combination of medicines in breastfeeding, or if you are thinking of advising against breastfeeding.

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