Pharmacology Flashcards
how might pregnancy physiologically change absorption of drugs?
Oral: decreased GI motility and increased GI blood flow due to progesterone
IM/SC/Inhaled/transdermal: increased blood flow to muscles, lungs, subcutaneous tissues
how might pregnancy change the PK effect of drugs?
oral: changes in rate and exten of absorption
IM/SC/ Inhaled/transdermal: potentially increases absorption
how might pregnancy physiologically change distribution of drugs?
increased plasma volume and cardiac output; redistribution of blood flow
plasma proteins: decreased albumin; increased acute phase proteins
how might pregnancy change the PK effect of drugs?
increased Vd possible with decreased plasma concentrations
increased free fraction of acidic drugs with increased distribution
how might pregnancy physiologially change the metabolism of drugs?
- increased hepatic blood flow
- decreased protein binding
- increase/decrease metabolizing enzymes
how might pregnancy change the PK effect of metabolism?
- increased delivery of high ER drigs to liver to metabolism
- increased delivery of free drug to liver for low ER drugs
- drug dependent increases or decreases in metabolism
how might pregnancy physiologically change elimination of drugs
increased renal blood flow and GFR, increased CO
how might pregnancy effect the PK of elimination of drugs?
increased renal elimination of hydrophilic drugs
molecular weight effect on drug transfer
smaller drugs have increased permeability
pKa effect on drug transfer with pregnancy
drugs can only cross the placenta in the unionized form; fetal pH is lower compared to maternal pH, therefore some drugs may undergo ion trapping and persist/accumulate in the fetus
protein binding effect on drug transfer with pregnancy
drugs can only cross the placenta if they are in the unbound form; drugs with lower protein binding will have increased permeability
concentration effect on drug transfer with pregnancy
higher concentrations in the maternal blood will result in a larger concentration gradient and greater diffusion of drug across the placenta
teratogenic drugs administered to dogs at therapeutic doses
griseofulvin
testosterone/estrogens
tetracyclines
trilostane/mitotane
teratogenic drugs administered to cats at therapeutic doses
griseofulvin
testosterone/estrogen
tetracyclines
teratogenic drugs administered to horses at therapeutic doses
griseofulvin
TMS, pyrimethamine, folic acid
teratogenic drugs administered to sheep at therapeutic doses
Oxfendazole, albendazole, febantel
antibiotics safe for use in pregnancy
beta lactams
macrolides
lincosamides
endocrine drugs safe for use in pregnancy
insulin and levothyroxine
heartworm preventatives safe for use in pregnancy
heartguard and revolution
flea and tick meds safe for pregnancy
frontline and maybe bravecto
t/f: it is possible to give a dose that is harmless to the mother and fatal to the fetus
T
when are fetuses the most susceptible to teratogenesis
the first trimester
- dogs day 14-30
- cats day 14-26
- horses less than day 60
how do drugs cause teratogenesis?
- alter gene expression of the fetus
- alter apoptosis, cell migration, cell proliferation
- alter synthesis and function of proteins and nucleic acids
- alter supply of energy sources
teratogen
an agent or factor that causes inflammation of an embryo
the placenta is an __ barrier
incomplete
what would cause increased placental drug transfer?
smaller molecular weight
higher lipid solubility
unionized
lower protein binding
higher concentration gradient
