Using beta-blockers during breastfeeding

Preferred choice

Labetalol is a preferred choice due to very small amounts in breast milk and more favourable pharmacokinetics although monitoring is still recommended.

Infant monitoring

As a precaution, monitor infants for signs of bradycardia or hypoglycaemia including drowsiness, lethargy, and poor feeding and inadequate weight gain.  Hypoglycaemia may also manifest as jitteriness/ tremors, sweating, irritability, fast breathing, looking pale, and unusual cry.

Further information

Limited published evidence indicates that levels in breast milk are generally very small. Most breastfed infants are likely to get less than 1% of maternal weight-adjusted dose via breast milk.

Labetalol is mostly metabolised in the liver, and its half-life in adults is 6-8 hours. The risk of accumulation in a breastfed infant is therefore low.

Most studies have not reported any adverse effects in breastfed infants.  One premature infant developed sinus bradycardia when exposed to labetalol via breast milk, suggesting additional caution is needed in very young or premature infants.

It is used therapeutically in infants from birth.

Preferred choice

Metoprolol is a preferred choice due to very small amounts in breast milk and favourable pharmacokinetics although monitoring is still recommended.

Infant monitoring

As a precaution, monitor infants for signs of bradycardia or hypoglycaemia including drowsiness, lethargy, and poor feeding and inadequate weight gain. Hypoglycaemia may also manifest as jitteriness/tremors, sweating, irritability, fast breathing, looking pale, and unusual cry.

Further information

Limited published evidence indicates that amounts in breast milk are generally very small. Most breastfed infants are likely to get less than 2% of the weight-adjusted maternal dose of metoprolol via breast milk.

Metoprolol is mostly metabolised in the liver, and its half-life in most adults is 3-7 hours, and 5-10 hours in neonates. However, metoprolol is metabolised by the hepatic cytochrome P450 2D6 enzyme. Some people do not have effective levels of this enzyme (“poor metabolisers”), resulting in slower metabolism and a half-life of 7-9 hours in adults, and presumably longer in neonates.  This may increase the risk of infant side effects.

The risk of significant accumulation in a breastfed infant is therefore relatively low, but not impossible, especially in very young infants.

It is used therapeutically in infants from the age of one month.

Preferred choice

Propranolol is a preferred choice due to very small amounts in breast milk and favourable pharmacokinetics although monitoring is still recommended.

Infant monitoring

As a precaution, monitor infants for signs of bradycardia or hypoglycaemia including drowsiness, lethargy, and poor feeding and inadequate weight gain. Hypoglycaemia may also manifest as jitteriness/tremors, sweating, irritability, fast breathing, looking pale, and unusual cry.

Further information

Limited published evidence indicates the amounts in breast milk are very small.  Most breastfed infants are likely to get less than 1% of the weight-adjusted maternal daily dose of propranolol via breast milk.

Despite propranolol almost being completely excreted in the urine, it is highly lipid soluble and highly protein bound, and has a half-life of 3-6 hours. Accumulation in a breastfed infant is therefore unlikely.

There have been no reported side effects in infants clearly attributed to exposure to propranolol via breast milk.

It is used therapeutically in infants from birth.

Use with caution

Atenolol is excreted into breast milk in small to moderate amounts.  It can be used with caution during breastfeeding, but labetalol, metoprolol, or propranolol are preferred if clinically appropriate..

Infant monitoring

Monitor infants for signs of bradycardia or hypoglycaemia including drowsiness, lethargy, and poor feeding and inadequate weight gain. Hypoglycaemia may also manifest as jitteriness/tremors, sweating, irritability, fast breathing, looking pale, and unusual cry.

Cyanosis and hypothermia have also been reported in an infant exposed to atenolol via breast milk.

Further information

Passage of atenolol into breast milk is variable. Milk levels higher than maternal plasma levels have been reported.

Most studies found that infants are likely to get 5-10% of the maternal weight-adjusted dose although higher figures, up to 35% have been reported. Infant atenolol plasma levels are therefore also very variable, ranging from undetectable to nearly 20% of the mother’s plasma level.

Atenolol is mainly excreted in the urine. Although its half-life in adults is only 3-8 hours, it is much longer in neonates (10-35 hours). There is therefore significant risk of accumulation of atenolol in breastfed infants, particularly neonates, resulting in increased risk of adverse effects.

In one report, a 5-day-old baby exposed via breast milk developed cyanosis, bradycardia, and hypotension, which resolved when atenolol was discontinued. Another paper reported lethargy.

It is used therapeutically in infants from birth.

Use with caution

Bisoprolol can be used with caution during breastfeeding, but labetalol, metoprolol, or propranolol are preferred if clinically appropriate.

Infant monitoring

Monitor infants for signs of bradycardia or hypoglycaemia including drowsiness, lethargy, and poor feeding and inadequate weight gain. Hypoglycaemia may also manifest as jitteriness/tremors, sweating, irritability, fast breathing, looking pale, and unusual cry.

Further information

Very limited published evidence is available. In one case report, bisoprolol was not detected in breast milk.

Its low protein-binding and high orally bioavailability suggests it is likely to be excreted into breast milk and be absorbed by the infant. Its half-life is 9-12 hours and it is at least 50% excreted in the urine, so there is some potential for accumulation in a breastfed infant.

Infant side effects have not been reported.  In one published case a premature infant was partly breastfed and showed no side effects to bisoprolol.

Use with caution

Carvedilol can be used with caution during breastfeeding, but labetalol, metoprolol, or propranolol are preferred if clinically appropriate.

Infant monitoring

Monitor infants for signs of bradycardia or hypoglycaemia including drowsiness, lethargy, and poor feeding and inadequate weight gain. Hypoglycaemia may also manifest as jitteriness/tremors, sweating, irritability, fast breathing, looking pale, and unusual cry.

Further information

There are no published reports of carvedilol being used during breastfeeding.

Carvedilol is highly lipid soluble, but is almost completely bound to plasma proteins. It is therefore only likely to get into breast milk in low levels.

Carvedilol is extensively metabolised by the liver, with a half-life of 6-10 hours in adults. However, it has a mean half-life of 2.2 hours in children (no data regarding neonates). Accumulation in a breastfed infant is therefore less likely than with other beta-blockers.

Use with caution

Nebivolol can be used with caution and infant monitoring during breastfeeding, but its pharmacokinetics are complex.  Labetalol, metoprolol, or propranolol are preferred if clinically appropriate.

Infant monitoring

Monitor infants for signs of bradycardia or hypoglycaemia including drowsiness, lethargy, and poor feeding and inadequate weight gain. Hypoglycaemia may also manifest as jitteriness/tremors, sweating, irritability, fast breathing, looking pale, and unusual cry.

Further information

There are no published reports of nebivolol being used during breastfeeding.

Nebivolol is highly lipid soluble, but is almost completely bound to plasma proteins. It is therefore likely to get into breast milk in low levels.

Nebivolol has active metabolites with a half-life of approximately 24 hours which increases the risk of accumulation in the infant. Also, it is metabolised by the hepatic cytochrome P450 2D6 enzyme. Some people do not have effective levels of this enzyme (“poor metabolisers”), resulting in higher levels of nebivolol and its active metabolites, and prolonged half-lives. This may increase the risk of infant side effects.

Seek further advice

As sotalol is usually used for its antiarrhythmic properties, another beta blocker is unlikely to be clinically suitable.  Contact us for advice.