Pregnancy and Lactation Flashcards
What physiologic changes happen in pregnancy?
Increased cardiac output, renal blood flow changes, hepatic blood flow changes, decreased GI motility, increase total body water, blood volume, and body fat affect distribution
What week in pregnancy does cardiac output increase?
8-10 weeks
Why are higher doses of metformin sometimes needed in pregnant patients?
creatinine clearance is increased
What enzymes and drugs are induced in pregnancy?
CYP3A and CYP2D6 like HIV antivirals, antihypertensive drugs, glucocorticoids and anti-epileptic drugs, antidepressants, beta blockers, codeine, and antihistamines
What enzymes and drugs are induced in pregnancy?
CYP 1A2 and CYP2C19 like caffeine, theophylline, cimetidine, fluoroquinolones, fluvoxamine, glyburide, PPI, diazepam, and propranolol
What GI changes that happen in pregnancy impact absorption?
N/V, increased gastric pH, delayed gastric emptying, and slowed intestinal motility
What pregnancy changes effect distribution?
Body water increases 5-8 liters, blood volume increases 50%, decreased plasma protein concentration makes for a higher concentration of free drug if it is highly protein bound, and drugs distributed to fat will have a longer half life
How is the Vd increased in pregnancy?
Th fetus and amniotic fluid become additional body compartments
When is a fetus able to metabolize drugs?
5-8 weeks gestation
What are two examples of fetal therapy?
Levothyroxine to prevent fetal hypothyroidism and dexamethasone for lung maturation for preterm birth
What is most critical for teratogenesis?
The timing and gestational age of a fetus
Early exposure teratogenesis causes-
organogenesis
Late exposure teratogenesis causes-
Functional abnormalities
What characteristics must a substance show to be teratogenic?
- results in a characteristic set of malformations 2. exert its effects at a particular state of fetal development 3. show a dose dependent incidence
What factors affect drug concentration in breast milk?
Timing: more drug is excreted in colostrum, polarity; less polar and lipid soluble pass into milk, Relative infant dose or RID; ratio of mother’s dose to milk dose, Drug route and formula (topical drugs are not absorbed in breast milk) Drugs with high VD easily go into milk, protein; higher the protein binding the less is in the milk; and maternal factors like dose and dosing intervals
T or F; meds enter the milk compartment only from the mother’s blood
True- if a drug is not absorbed into the plasma compartment it does not enter teh milk compartment
What drug category poses a major risk to a breastfeeding infant?
Codeine
How does the placenta modulate drug PK parameters?
It mediates nutrients and toxic byproducts between mother and fetal circulation. Small molecular weight and lipophilic drugs readily pass by simple diffusion across the placenta
