Safety of antihistamines during pregnancy and lactation

QUESTION Many of my pregnant and breastfeeding patients suffer from allergies and frequently ask me about the safety of antihistamines during pregnancy and breastfeeding. Should I advise them to use the older sedating medications? I have heard that they might be safer than the newer nonsedating class of drugs. Or have the newer ones been studied as well? ANSWER First-generation antihistamines are considered safe to use during pregnancy. There are relatively fewer data on the nonsedating second-generation antihistamines; however, published studies are reassuring. All antihistamines are considered safe to use during breastfeeding, as minimal amounts are excreted in the breast milk and would not cause any adverse effects on a breastfeeding infant.