TY - CHAP M1 - Book, Section TI - Maternal–Fetal Pharmacology A1 - Hopkins, Amanda N. A1 - Berger, Jeffrey S. A2 - Freeman, Brian S. A2 - Berger, Jeffrey S. PY - 2016 T2 - Anesthesiology Core Review: Part Two Advanced Exam AB - Fetal exposure to drugs is determined primarily by maternal pharmacokinetics, route and timing of drug administration, changes in uterine blood flow, and placental permeability. Drugs that are rapidly metabolized by the mother, such as chloroprocaine, are unlikely to appear in the fetal circulation in significant amounts. The route of administration (e.g., oral, intravenous, intrathecal, epidural) dictates fetal exposure just as it determines maternal blood concentration. The dose and timing of administration is also important, as even drugs with low placental permeability may accumulate in the fetus if they are given in large doses or continually administered (e.g., as an intravenous infusion) over a longer period of time. A drug given during periods of minimized uterine blood flow, such as during a uterine contraction, is unlikely to reach the fetus, regardless of its placental permeability. Finally, there are multiple factors inherent to the drug itself that determine its likelihood of passing through the placenta (Table 156-1). SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=1135742858 ER -