Very limited data suggest breastmilk levels are likely to be low, but other medicine classes are preferred. Recommendations apply to full term, healthy infants.
There is almost no published evidence of the use of any medicine in this class during breastfeeding.
If there are no other therapeutic options, angiotensin-II receptor antagonists can be used with caution during breastfeeding. Candesartan, losartan or valsartan have the most favourable pharmacokinetics and would therefore be preferred. However, given the very limited published evidence it would usually be preferable to choose a medicine from a different class which has more information supporting their use in breastfeeding.
Milk levels of all angiotensin-II receptor antagonists are expected to be low, based on very limited published evidence and pharmacokinetic parameters. They all have high plasma protein binding making it unlikely that they will be excreted into breastmilk to any great extent. Most have low to moderate oral bioavailability which limits the amount absorbed by the infant.
Candesartan, losartan or valsartan have the lowest oral bioavailability and shortest half-lives, making them preferred choices. In addition, candesartan has limited published evidence supporting its use in breastfeeding. Irbesartan and telmisartan have the longest half-lives and highest bioavailability and therefore are the least preferred options from this class.
Indications
Recommendations apply to any indication the medicine is being used for, such as hypertension, heart failure or post-myocardial infarction.
Choice of antihypertensive
Choice of anti-hypertensive in breastfeeding will be dependent on a number of factors, including patient-specific characteristics, clinical condition and patient preference.
Medicines from different pharmacological classes may need to be used in combination and therefore their additive safety in breastfeeding will need to be considered.
Treatment choice should primarily be directed at controlling symptoms, with safety in breastfeeding a secondary consideration.
Neonates and infants less than 2 months are at the most risk from the side-effects of angiotensin-II receptor antagonists, particularly hypotension, because they have underdeveloped clearance capacities, which means they can’t metabolise the medicines as effectively.
In addition, there is theoretical concern that angiotensin-II receptor antagonists could affect kidney development. However, this has not been proven.
If an angiotensin-II receptor antagonists is the best therapeutic option, extra caution should be taken when breastfeeding younger infants and neonates.
Specific recommendations
Use with caution
Candesartan can be used with caution during breastfeeding if it is specifically clinically indicated. However a medicine from a different therapeutic class which has more evidence in breastfeeding is preferred.
Infant monitoring
As a precaution, monitor the infant for hypotension which may manifest as drowsiness, lethargy, looking pale, poor feeding and inadequate weight gain.
In younger infants, monitor for normal urine production (wet nappies).
Further information
Limited evidence from three women shows that candesartan passes into breast milk in very small amounts (0.8–1% of the weight-adjusted maternal candesartan dose) with maternal daily doses 8mg to 32mg for at least 2 weeks.
It has a shorter half-life meaning it is less likely to accumulate in the infant, and its low to moderate oral bioavailability suggests it would not reach the infant’s serum in significant levels.
Infant plasma levels were less than 0.2micrograms/L.
No infant side-effects have been reported from exposure via milk.
Use with caution
Losartan can be used with caution during breastfeeding if it is specifically clinically indicated. However a medicine from a different therapeutic class which has more evidence in breastfeeding is preferred.
Infant monitoring
As a precaution, monitor the infant for hypotension which may manifest as drowsiness, lethargy, looking pale, poor feeding and inadequate weight gain.
In younger infants, monitor for normal urine production (wet nappies).
Further information
There is no information on excretion of losartan in breast milk.
As with other angiotensin-II receptor antagonists, it would be expected to be excreted into breast milk in low amounts. It has a shorter half-life meaning it is less likely to accumulate in the infant, and its moderate oral bioavailability suggests it would not reach the infant’s serum in significant levels.
No infant side-effects have been reported from exposure via milk.
Use with caution
Valsartan can be used with caution during breastfeeding if it is specifically clinically indicated. However a medicine from a different therapeutic class which has more evidence in breastfeeding is preferred.
Infant monitoring
As a precaution, monitor the infant for hypotension which may manifest as drowsiness, lethargy, looking pale, poor feeding and inadequate weight gain.
In younger infants, monitor for normal urine production (wet nappies).
Further information
There is no information on excretion of valsartan in breast milk.
As with other angiotensin-II receptor antagonists, it would be expected to be excreted into breast milk in low amounts. It has a shorter half-life meaning it is less likely to accumulate in the infant, and its low oral bioavailability suggests it would not reach the infant’s serum in significant levels.
No infant side-effects have been reported from exposure via milk.
Use with caution
Irbesartan has less favourable pharmacokinetics than candesartan, losartan or valsartan. It can be used with caution during breastfeeding if there are specific clinical indications for it. However a medicine from a different therapeutic class which has more evidence in breastfeeding is preferred.
Infant monitoring
As a precaution, monitor the infant for hypotension which may manifest as drowsiness, lethargy, looking pale, poor feeding and inadequate weight gain.
In younger infants, monitor for normal urine production (wet nappies).
Further information
There is no information on excretion of irbesartan in human breast milk.
As with other angiotensin-II receptor antagonists, it would be expected to be excreted into breast milk in low amounts. Its longer half-life and higher oral bioavailability make it a less favourable choice than other angiotensin-II receptor antagonists but, infant exposure should still be minimal based on its high protein binding.
No infant side-effects have been reported from exposure via milk.
Use with caution
Olmesartan has less favourable pharmacokinetics than candesartan, losartan or valsartan. It can be used with caution during breastfeeding if there are specific clinical indications for it. However a medicine from a different therapeutic class which has more evidence in breastfeeding is preferred.
Infant monitoring
As a precaution, monitor the infant for hypotension which may manifest as drowsiness, lethargy, looking pale, poor feeding and inadequate weight gain.
In younger infants, monitor for normal urine production (wet nappies).
Further information
There is no information on excretion of olmesartan in breast milk.
As with other angiotensin-II receptor antagonists, it would be expected to be excreted into breast milk in low amounts. Its relatively longer half-life makes it a less favourable choice but infant exposure should be minimal based on its high protein binding and low oral bioavailability.
No infant side-effects have been reported from exposure via milk.
Use with caution
Telmisartan has less favourable pharmacokinetics than candesartan, losartan or valsartan. It can be used with caution during breastfeeding if there are specific clinical indications for it. However a medicine from a different therapeutic class which has more evidence in breastfeeding is preferred.
Infant monitoring
As a precaution, monitor the infant for hypotension which may manifest as drowsiness, lethargy, looking pale, poor feeding and inadequate weight gain.
In younger infants, monitor for normal urine production (wet nappies).
Further information
There is no information on excretion of telmisartan in breast milk.
As with other angiotensin-II receptor antagonists, it would be expected to be excreted into breast milk in low amounts. Its longer half-life makes it a less favourable choice but infant exposure should be minimal based on its very large volume of distribution and high protein binding.
No infant side-effects have been reported from exposure via milk.
the angiotensin-II receptor antagonist in question is not included in our advice
you need further advice
About our recommendations
Recommendations are based on published evidence where available. However, evidence is generally very poor and limited, and can require professional interpretation. Assessments are often based on reviewing case reports which can be conflicting and lack detail.
If there is no published clinical evidence, assessments are based on: pharmacodynamic and pharmacokinetic principles, extrapolation from similar drugs, risk assessment of normal clinical use, expert advice, and unpublished data. Simulated data are now increasingly being used due to the ethical difficulties around gathering good quality evidence in this area.