# 10 - General principles of prescribing psychotropi

# General principles of prescribing psychotropics in breastfeeding

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The Maudsley® Prescribing Guidelines in Psychiatry
CHAPTER 7
Drug choice in breastfeeding
The long-­term benefits of breastfeeding on a child’s physical health and cognitive development are well known. Women are generally encouraged to breastfeed for at least 
6 months. One factor that may influence a mother’s decision to breastfeed is the safety 
of a drug taken while breastfeeding. With some notable exceptions, most psychotropic 
drugs should be continued in breastfeeding women because of the benefits of breastfeeding and the lack of evidence of harm for most drugs. However, current evidence 
suggests that for a few drugs the woman should be advised not to breastfeed if such 
medications are the best and only option for her care.
Data on the safety of psychotropic medication in breastfeeding are largely derived 
from small studies or case reports and case series. Reported infant and neonatal outcomes in most cases are limited to short-­term acute adverse effects. Long-­term safety 
cannot therefore be guaranteed for the psychotropics mentioned here. The information 
presented must be interpreted with caution with respect to the limits of the data from 
which it is derived and the need for such information to be regularly updated.
There are two distinct clinical scenarios. In the first, the mother will have been taking 
the psychotropic drug(s) during pregnancy and often up until birth. In these people, the 
same psychotropic(s) should be continued during breastfeeding to mitigate withdrawal 
symptoms in the neonate (but see exceptions later). In the second, the mother is newly 
prescribed a psychotropic after the child has been born but wishes to breastfeed. 
Decisions in this scenario are rather more complex and the reader is referred to the 
tables in this section.
Infant exposure
All psychotropics are excreted in breast milk to varying degrees. The most direct measure of infant exposure is, of course, infant plasma levels but these data are rarely available. Instead, many publications report only drug concentrations in breast milk and in 
maternal plasma. Maternal plasma levels of antipsychotics may be a useful estimate of 
infant exposure.1 Breast milk drug concentrations can be used to estimate the daily 
infant dose (by assuming a milk intake of 150mL/kg/day). The infant weight-­adjusted 
dose when expressed as a proportion of the maternal weight-­adjusted dose is known as 
the relative infant dose (RID). The RID should be used as a guide only, as values are 
estimates and these estimates vary widely in the literature for individual drugs.
Drugs with an RID below 10% are usually regarded as safe in breastfeeding. Where 
measured, infant plasma levels below 10% of average maternal plasma levels have also 
been proposed as being safe in breastfeeding.2
General principles of prescribing psychotropics in breastfeeding
■
■The safety of individual drugs in breastfeeding should be taken into account when 
prescribing psychotropic medication for women considering pregnancy.
■
■Discussions about the safety of drugs in breastfeeding should be held as early as 
­possible – ideally before conception or early in pregnancy. Decisions about the use of 
drugs in pregnancy should include the discussion about breastfeeding. Switching 
drugs at the end of pregnancy or in the days after birth is not advisable because of the 
high risk of relapse.