RT Book, Section
A1 Hopkins, Amanda N.
A1 Berger, Jeffrey S.
A2 Freeman, Brian S.
A2 Berger, Jeffrey S.
SR Print(0)
ID 1135742858
T1 Maternal–Fetal Pharmacology
T2 Anesthesiology Core Review: Part Two Advanced Exam
YR 2016
FD 2016
PB McGraw-Hill Education
PP New York, NY
SN 9781259641770
LK accessanesthesiology.mhmedical.com/content.aspx?aid=1135742858
RD 2024/04/25
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).