Hi Lactnetters! There is no available info on the newer antihistamines, but as a rule of thumb we should inform the mother that she should go for shorter acting drugs (the ones being taken every six hours). The longer acting drugs can accumulate in the baby's system. If any of you had an allergy test done you must have been told that you had to wait one week or so after the last dose of a shorter acting drug or 30 days after the last dose of a longer acting drug. I am not a pharmacist but one can assume that Claritin, Seldane, Hismanal and Reactine should be avoided. Dany Gauthier IBCLC [log in to unmask] Montreal, Canada Tel: 514-923-3792 Fax:514-923-3802