Population Specific Pharmacotherapy Flashcards
Two membranes of the placental barrier
ST (syncytiotrophoblastic layer)
CT (cytotrophoblastic layer)
Which placental barrier layer is outside?
ST
Which placental barrier layer is on the inside?
CT
What is the purpose of the placental barrier?
to serve as a barrier preventing drug transport across the placenta
What are 3 characteristics that make a substance cross the placental barrier easier?
low molecular weight, un ionized, higher lipophilicity
in terms of placental permeability, lipid permeability is directly proportional to ______ and permeability is inversely proportional to _______
lipophilicity; molecular size
medications sized <500 Da
cross placental barrier easily
medications sized 500-1000 Da
cross with difficulty
medications sized >1000 Da
cross very poorly
Medications with high lipophilicity and low molecular weight will
cross the placenta easily
Protein bound drugs and placenta
Free form may cross but anything bound to protein would have difficulty
Drug movement across the placental membrane is reduced by
efflux transporters
What are the transporters that exist on the membrane of the placenta? (4)
P-glycoprotein
BCRP
MRP1
MRP2
In what layer of the placental barrier are phase I and phase II enzymes located?
ST
the amount of enzymes in the placental barrier are much ___ than in the liver
less
amount of enzymes in the placental barrier change with _____
gestational age
Metabolism of meds that pass through the placental barrier
small amount of metabolism takes place. if they do pass through and are not effluxed out, they can pose potential harm to the fetus.
4 different types of drugs that reach the fetus
- drugs which have favorable effects on the fetus
- drugs which have no effect on the fetus
- drugs that have adverse effects on the fetus
- teratogens which are drugs that effect embryonic of fetal development.
Always check ____ when prescribing meds to pregnant women
teratogenicity
If toxicities occur in the placenta between weeks 3 and 8, what can you expect?
abnormalities in development of the fetus
What needs to be considered if a mother really requires a medication during fetal development?
how severe is the potential effect? is it temporary or permanent?
teratogens
medications that will cause malformation of an embryo
Teratogenic effects most often occur during
organogenesis
Expression of teratogenic effects depend on
drug
fetal variability