Perinatal pharmacology and safety profiles.

Most medications are not adequately evaluated for use during pregnancy, delivery, or the postpartum period, and package inserts fail to provide clear instructions for use in these contexts, despite major concerns among health-care providers and the community as to how to practice evidence-based pharmacotherapy. Valproate fetopathy hereby serves as one of the more recent illustrations of the scope of the problem. At its best, evidence-based pharmacotherapy is driven by a balanced decision between disease-related risks (natural course of the disease) and any risks related to exposure to medications for mother, fetus, or infant. This chapter aims to describe the general patterns of changes in pharmacokinetics (absorption, distribution, metabolism, elimination) in pregnant women and postpartum, with specific emphasis on placental drug transport and additional focus on lactation. The relevance of these changes is illustrated by discussing medications commonly prescribed to treat neurologic conditions.