Cetirizine and loratadine are preferred antihistamines when breastfeeding full-term, healthy infants. Chlorphenamine is the preferred sedating antihistamine.
Cetirizine or loratadine are the preferred non-sedating antihistamines during breastfeeding.
If a sedating antihistamine is necessary, chlorphenamine is preferred due to extensive experience of use during breastfeeding.
Very limited studies are available, and data on long-term exposure are lacking. However, most antihistamines can be used during breastfeeding if clinically indicated.
Monitor the infant and use the lowest effective dose for the shortest time possible; occasional doses are preferred, particularly with the sedating antihistamines.
Choice considerations
Treatment choice should primarily be directed at managing the clinical condition, with safety in breastfeeding a secondary consideration.
Intranasal or topical antihistamines are preferred options if clinically appropriate for managing symptoms. Such preparations are likely to give very small or negligible systemic concentrations, leading to negligible concentrations in breast milk.
Adverse effects
All antihistamines can potentially cause drowsiness to varying extents, although this is much more likely with a sedating antihistamine. Using any antihistamine can increase the risk of drowsiness in the breastfed infant, but particularly when a sedating antihistamine is used. Using larger doses, long courses or taking alongside other sedative medicines increases the risk of infant drowsiness.
Drowsiness can manifest as not waking to feed, falling asleep during feedings, sleeping for longer, and sleeping more often than expected.
Younger, exclusively breastfed infants are at greater risk of getting side effects.
Monitoring the infant should quickly identify potential issues. However, further investigation is usually required before a cause can be attributed to the medicine.
Co-sleeping advice
Sudden infant death syndrome (SIDS) is very rare, and breastfeeding reduces the risk. However it is more likely to happen in certain circumstances, including when parents have taken sedating medicines.
Limited and conflicting data exist on the effect of antihistamines on breast milk production.
Antihistamines, used at normal therapeutic doses, are unlikely to affect breast milk production, especially where lactation is established (usually around 6 to 8 weeks postpartum).
A small study found that promethazine during labour may have delayed milk secretion. High doses of dexchlorphenamine or promethazine have reportedly decreased basal serum prolactin levels. The significance of this in breastfeeding individuals is not known.
Occasional cases of reduced milk supply have been reported with loratadine and cetirizine.
If there is difficulty breastfeeding, particularly with establishing breastfeeding, additional breastfeeding support may be required.
Specific recommendations
We provide specific advice for both non-sedating and sedating antihistamines.
Non-sedating antihistamines
Use with caution
Cetirizine is a preferred choice during breastfeeding, but infant monitoring is still required.
Monitoring
As a precaution, monitor the infant for potential side effects including drowsiness, irritability, dry mouth, poor feeding and inadequate weight gain.
Further Information
There is extensive experience of use during breastfeeding, but limited published information.
Studies have shown very small amounts in milk (up to 1.9% of the weight-adjusted maternal dose). Infant serum levels have not been measured.
Most studies report no infant side effects. A few cases of reduced milk supply have been reported.
Loratadine is a preferred choice during breastfeeding, but infant monitoring is still required.
Monitoring
As a precaution, monitor the infant for potential side effects including drowsiness, irritability, poor feeding and inadequate weight gain.
Further Information
There is extensive experience of use during breastfeeding, but limited published information.
One report found that doses of up to 40mg result in very small amounts of loratadine and its metabolite in breast milk (up to 1.1% of the weight-adjusted maternal dose). Infant serum levels have not been measured.
In a survey of 51 breastfeeding mothers taking loratadine, there were two reports of minor infant sedation and one report of decreased milk production. No other side effects were noted.
Fexofenadine can be used with caution during breastfeeding, but infant monitoring is required. Cetirizine or loratadine are preferred.
Monitoring
As a precaution, monitor the infant for potential side effects including drowsiness, irritability, poor feeding and inadequate weight gain.
Further information
Fexofenadine is an active metabolite of terfenadine. Only terfenadine has been studied during breastfeeding.
Very limited evidence shows that after taking terfenadine, negligible amounts of fexofenadine pass into breast milk (less than 0.45% of the weight adjusted maternal dose). These amounts would not be expected to cause adverse effects.
In another study, terfenadine was used by 25 breastfeeding mothers; mild irritability was reported in three breastfed infants.
Infant serum levels have not been measured.
Use with caution
Acrivastine can be used with caution during breastfeeding if necessary, but close infant monitoring, particularly for drowsiness, is required. Cetirizine or loratadine are preferred.
Monitoring
As a precaution, monitor the infant for potential side effects including drowsiness, irritability, dry mouth, poor feeding and inadequate weight gain.
Further information
There is no published evidence on the use of acrivastine in breastfeeding. Based on its pharmacokinetic properties it is likely to pass into breastmilk in small to moderate quantities.
Although acrivastine is classed as a non-sedating antihistamine, it can very commonly cause drowsiness when given directly.
Sedating antihistamines
Use with caution
Chlorphenamine is the preferred choice of sedating antihistamine, but infant monitoring is required; it’s best to take it occasionally or for a short time. A non-sedating antihistamine is preferred.
Monitoring
As a precaution, monitor the infant for potential side effects including drowsiness, irritability, dry mouth, poor feeding and inadequate weight gain.
Further information
No published studies have measured breast milk levels, but there is extensive experience of its use whilst breastfeeding. Infant serum levels have also not been measured.
Based on its pharmacokinetic properties, low amounts are expected in breastmilk. Its low oral bioavailability will further limit absorption by the infant. Infant side effects are therefore not expected and none have been reported in breastfed infants.
It is used therapeutically in infants from one month old.
Use with caution
Hydroxyzine can be used with caution during breastfeeding, but infant monitoring is required; it’s best to take it occasionally or for a short time. A non-sedating antihistamine or chlorphenamine is preferred.
Monitoring
As a precaution, monitor the infant for potential side effects including drowsiness, irritability, dry mouth, poor feeding and inadequate weight gain.
Further information
No published studies have measured breast milk levels, but based on its pharmacokinetic properties, low amounts are expected.
Hydroxyzine is largely metabolised into cetirizine, which is a preferred antihistamine during breastfeeding.
Hydroxyzine has been reported to cause side effects, primarily sedation, in some breastfed infants.
Use with caution
Promethazine can be used with caution during breastfeeding, but infant monitoring is required; it’s best to take it occasionally or for a short time. A non-sedating antihistamine or chlorphenamine is preferred.
Monitoring
As a precaution, monitor the infant for potential side effects including drowsiness, irritability, dry mouth, poor feeding and inadequate weight gain.
Further information
There is no published evidence of use during breastfeeding. Milk levels have not been measured.
Based on its pharmacokinetic properties, it is likely to be found in breastmilk in low amounts. Its low oral bioavailability will further limit absorption by the infant.
Although not specifically studied, no side effects have been reported in breastfed infants. Promethazine may affect milk production (see ‘effect on breast milk production’ section for further information).