Drugs & Pregnancy Flashcards
3 physiologic changes in pregnant women that affect drug metabolism
- increased volume
- increased flow
- reduced plasma protein binding
What happens to GFR during pregnancy?
increased
Rule of thumb for drugs in pregnany
None unless absolutely necessary
Two main concerns when considering drug therapy in pregnant women…
teratogenic?
affect fetus near term?
Which category?
animal/human studies demonstrate risk.
Risk outweighs benefits
Category X
Which category?
Human studies demonstrate risk
potential benefits may outweigh risk
Cat D
Which Category?
animal studies demonstrate risk, no human studies performed
benefits may outweigh risk
Cat C
Under new label, 8.1 indicates not safe for…
pregnancy
Under new label, 8.2 indicates not safe for…
lactation, nursing mothers
Under new label, 8.3 indicates not safe for…
females and males of reproductive potential
Why is drug absorption slowed in pregnancy?
high progesterone = slow gut motility/emptying
Why are drugs more rapidly metabolized during pregnancy?
pregnancy induces hepatic metabolizing enzymes
Why are drugs eliminated more rapidly during pregnancy?
increased RPF and GFR
What causes the change in volume of distro, absorption, excretion, plasma binding during pregnancy?
increased blood volume
The placenta is a _____ barrier that has many transporters on the surface, making it a ________
semipermeable
site of metabolism
drugs that have crossed the placenta enter fetal circulation via
_________.
About ________ of the venous blood flow enters the fetal liver
umbilical v.
40-60% to fetal liver
If the fetal liver only partially metabolizes a drug, what 2 mechanisms can allow the drug to re-enter the fetal ciruculation?
exit via umb. a. and subsequent reentry via umb. v.
OR
elimination in fetal urine and re-entry via swallowing amniotic fluid
What lipid solubility diffuses rapidly across placenta?
lipophilic
MW < ________ crosses placenta easily while > ________ crosses poorly.
< 500 = easy passage
> 1000 = poor passage
Do ionized or non-ionized molecules pass the placenta more easily?
non-ionized
What fetal transporter can pump drugs back into maternal circulation and out of fetal circ?
MDR-1
Which 3 conditions during pregnancy may require treatment?
HTN
Hyperglycemia
Thyroid Hormone Replacement
Diethyl stilbestrol taught us what?
teratogenic effects not always seen immediately
What teratogen?
- intellectual disability
- underdeveloped top of ear
- short nose
- thin upper lip
- small eye openings
- low nasal bridge
- epicanthal folds
- indistinct philtrum
- curved fifth finger
FAS
The buildup of ______ leads to FAS
acetaldehyde and EtOH
Patient presents with:
saddle nose depressed nasal bridge epiphyseal stippling vertebral calcification short neck
warfarin syndrome
What can be used instead of warfarin for mothers who need anticoagulation?
LMWH
Describe the exposure needed for isotretinoin to cause birth defects…
once in first 3 weeks
Women taking isotretinoin must follow the iPLEDGE program, which requires what?
neg preg
2 forms bc
continue one month after therapy
Which 4 anticonvulsants represent the safest option for pregnant women?
Gabapentin
Levetiracetam
Lamotrigine
Clonazepam
Which anticonvulsant is the most dangerous?
valproate
Which anticonvulsant can cause the below? What is the condition called?
- cleft lip/palate
- congenital heart disease
- slowed growth
- mental deficiency
Phenytoin
Fetal hydantoin syndrome
Which anticonvulsant can cause the below?
craniofacial anomalies
developmental delay
mental deficiency
Carbamazepine
This anticonvulsant has a 20-fold incrase in neural tube defects
valproate
Patient presents with:
- short left forearm and absent thumb
- left ulnar deviation, contracture of fingers at PIP
- broad forehead, thin eyebrows
- flat nasal bridge
- thin upper lip
fetal valproate syndrome
Ribavirin can cause…
intrauterine fetal death
Is ribavirin teratogenic in men, women, or both?
both
