Cetirizine can cause, among other symptoms, drowsiness and reduced milk secretion, especially concurrently with sympathomimetic drugs. It may also produce irritability and colic, although it has not clearly demonstrated the relationship between the substance and these manifestations.
If necessary its use, the most appropriate would administer just before going to sleep, although it is probably better to use an antihistamine that does not cross the blood-brain barrier, such as loratadine.
No information is available about the drug concentration in breast milk or infant. Antihistamines may reduce basal prolactin secretion in non-lactating women and during the postpartum period, which should be considered before prescribing these substances.
Warning of the manufacturer:
There are no relevant data about cetirizine excretion into breast milk. Cetirizine is contraindicated in women during the period of breastfeeding.