Drug therapy during pregnancy and lactation.

This article reviews the altered physiology of pregnancy and its impact on drug pharmacokinetics together with the pharmacokinetics of drug transport across the placenta and into the breast milk. Also reviewed are the potential adverse effects of maternal drug therapy on the fetus and neonate and the difficulties in assessing the potential risks of therapy. Finally, these principles are applied in the discussion of a number of specific drugs frequently prescribed in the emergency department setting.