Sept18 A1-Drugs in pregnancy Flashcards
pregnancy related changes in drug metabolism
- higher GFR
- higher CO (HR and SV), lower BP
- decreased gastric emtpying, prolonged transit time, GI reflex, nausea and vomiting, decreased intestinal motility, less metabolizing enzymes
- increase or decrease in fct of certain liver enzymes (CYP1A2 decreased activity)
caffeine metab change in pregnancy
increased half life (a lot) because of decreased CYP1A2 activity)
thalidomide is what
anti-nausea drug
what would happen to children of pregnant mother who took thalidomide
phocomelia (thalidomide embryopathy): no upper limbs
% of babies born in Canada every year with a major malformation visible at birth
3%
general principles of teratology (study of birth defects)
- susceptibility to a substance varies with dev stage (gestational age)
- each agent (substance) can access specific developing tissues
- abnormal dev may be manifested as death, malformation, growth retardation and or functional decficit
- more exposure = more manifestation of abnormal dev (from no effect to lethal)
time of maximal sensitivity to thalidomide
when limbs are developing
-so most sensitive time to a substance = time when the organs this substance affects are developing
teratogenic agents in humans
- radiation
- infections (TORCH, Zika virus, etc.)
- maternal and metabolic imbalance (diabetes is an important one)
- drugs and envrionmental chemicals
important teratogenic drugs in humans
- ethanol
- retinoids
- tetracyclines
- thalidomide
zika effects
- microcephaly (small head)
- fetal brain defects
zika transmission
- vertical
- during intercourse
- from mosquito bite
fetal alcohol spectrum disorder (FASD) is what
- all the lifelong lasting disorders and symptoms related to having been exposed to alcohol in utero (CNS abnormalities, growth retardation, facial abnormalities)
- more alcohol = more effects
leading cause of developmental disabilities in Canadian children
fetal alcohol spectrum disorder
major problem of FASD
effect on IQ
other sx of FASD
thin upper lip, specific facial features, etc.
how retinoids found to be teratogenic
isotretinoin was a retinoid used for severe acne. known to be teratognic bc of experiences on mammal species but pregnant women still took it
tetracycline is what
antibacterial drug. in the embryo
- it kelates and binds minerals in teeth and bones
- bone dev and teeth dev defects
problem with drugs in pregnancy
-old, legacy drugs have never had studies done for teratogenicity (like aspirin used since 1880..)
(new drugs do though)
-most commonly used meds have no evidence on risk or safety for the embryo
how testing for developmental toxicity of drugs is done today
- epi studies (retro or prospective)
- animal testing (in vivo)
- in vitro (whole embryo or embryonic SCs of animals)
when to tx disease 100% in a pregnant woman (when to give a drug)
if the disease presents a risk for both her and the fetus
- epilepsy (anticonvulsants are teratogenic, but new ones less)
- cancer
- depression
- others
teratogenic anticonvulsants
- valproic acide
- phenytoin
- carbamazepine
- phenobarbital
important supplement for pregnant women
folic acid (reduces risk of spina bifida and myelomeningocele but increased risk of congenital heart disease)
other prevention strategies to protect the fetus
vaccines (rubella for ex)
5 weeks pregnant with twins with nausea and vomiting of pregnancy (NVP) what you can do
dicelctin is the only med approved for that in Canada. (contains doxylamine (antihistamine) and vitamin B6)
how much fish can a pregnant woman eat (risk of mercury?)
- avoid large fish like tuna
- know what fish to avoid (ones with accumulated persistent organic pollutants like Hg)
- wallet cards for pregnant women telling the doses
