Antenatal and Prenatal Pharm - Fitz Flashcards
Rating pregnancy categories of drugs does NOT take into account what?
Does not account for risks via breast milk spread of drugs or metabolites
Can drugs in classes C or D cause harm in pregnancy?
YES, just not to everyone
LAST organ to properly develop for extra-uterine life?
Problem with this?
Example of case where this will be relevant?
Lungs
Surfactant deficiency is common in premature babies (before 32 weeks), leading to RDS
Pre-eclampsia/HELLP –> preterm C-section
A mother has pre-eclampsia at 30 weeks (or any case requiring pre-term delivery) and requires pre-mature C-section. What is the baby at risk for?
Drug to give to help prevent this? When?
Which ones are ok? Why?
MoA?
RDS (surfactant deficiency)
Corticosteroids - PRIOR to delivery (antenatal)
Betamethasone or Dexamethasone – no mineralocorticoid action
Binds GCR, causing inhibitor (hsp90) disassociation, then translocation of active GCR into the nucleus, then transcription of surfactant in TYPE 2 pneumocytes
Risks of antenatal corticosteroids - single vs. multiple courses
Single course = NONE
Multiple courses = growth defects, sepsis, brain delay, adrenal insufficiency, enterocolitis, etc.
Contraindications of antenatal corticosteroids
Mother w/ TB or systemic infection
Why is simple cortisol not given in antenatal period for premies?
Inactivated by 11-beta-HSD2 in the PLACENTA, thus fetus only gets CORTISONE
Describe physiology of labor induction
- Estrogen (ovaries) induces oxytocin receptor expression on uterus
- Stretch receptors in uterus cause oxytocin release (P. pituitary)
- Oxytocin causes BOTH uterine contraction AND PGF2-alpha release (placenta), which ALSO stimulates uterine contraction
What is the function of PGE2 in labor?
Cervical ripening
Drugs required for inducing labor (w/ MoA)
Dinoprostone (PGE2) or Misoprostol (PGE1) = cervical ripening
Oxytocin = uterine contractions
How is Dinoprostone administered?
Side effects?
So?
As suppository by the cervix
Diarrhea (stimulation of GI smooth muscle too) or uterine hyperstimulation
Has string attached to suppository for easy removal if side effects are bad
A deficit (natural or induced) in PGs will cause what in a pregnant woman?
An excess (natural or induced) in PGs will cause what in a pregnant woman?
Delayed birth
Premature labor/birth
What else is being monitored when using oxytocin for labor induction?
Fetal heart strength – oxytocin diverts blood from fetus to uterus, thus testing the fetal heart capability to respond
Tocolytic drugs - what are they?
One to use in Pre-eclampsia/HELLP? Why?
Labor-delaying drugs
Magnesium Sulfate – protects from seizures in eclampsia
4 different MoA’s of tocolytic drugs
- Beta-2 agonists
- Ca++ channel antagonists
- COX inhibitors
- Oxytocin receptor antagonists
Where does COX come from in labor induction?
Placenta and myometrium
COX-1 inhibitors used as tocolytics
MoA
Indomethacin
Ibuprofen
Inhibit COX-1, thus reduce PGE2 and PGF2-alpha synthesis, thus reduce uterine contractions
Oxytocin receptor antagonist used as tocolytic
MoA
Atosiban
Reduce uterine contractions
Ca++ channel blockers used as tocolytics
MoA of each
Nifedipine
MgSO4
Nifedipine = directly inhibit voltage-gated L-type Ca++ channel entry into myometrium
MgSO4 = competitive inhibitor at Ca++ chanels
Beta-2 agonists used as tocolytics
MoA
Ritodrine, Terbutaline, Salbutamol
Increased intracellular cAMP –> reducing uterine contractions
Beta-2 agonists - side effects
Tachy, hypotension, HYPOKALEMIA, HYPERGLYCEMIA
Indomethacin – used when (as tocolytic)?
Side effects (mother and fetus)
2nd trimester ONLY
Fetus – facial defect (1st trimester), premature closing of ductus arteriosus (3rd trimester)
Mother – bleeding, ulcers
Ca++ channel blockers - side effects
Nifedipine – dizziness, hypotension
MgSO4 – contraindication
Myasthenia gravis
Physiology of DA closure
Inactivation of PGE2, causing closure
Drug used to maintain PDA
In who?
Alprostadil (PGE1)
Congenital heart disorders (cyanotic, low PO2, need additional blood flow to heart) – until they can be cured surgically
Side effects of Alprostadil
Limiting effect of Alprostadil administration
Hypotension, tachycardia, apnea, PYREXIA (fever)
Fever
Drug used to close PDA
In who?
Indomethacin (NSAID)
PREMATURE infants that can’t close the DA on their own
A woman gives birth to a baby at term (40 weeks). The baby’s PDA does not close at birth, and the baby begins to develop LE cyanosis and RVH. Treatment?
Surgery (NOT an NSAID - too late)
Indomethacin (as PDA closer) – side effects
Renal vascular constriction (no COX-1) –> oliguria, edema, high creatinine, mild hypertension
Any drug that is cleared _____ must be a reduced dose in kids under 6 months
Renally
Sulfamethoxazole in infants
CONTRAINDICATED – kernicterus (inhibits ability to clear bilirubin in kids)
Chloramphenicol in infants
CONTRAINDICATED - gray baby syndrome (V/D, circulatory collapse, abdominal distention, dusky gray color
Class B antibiotics (pregnancy) - ok to use
Cephalosporins, Penicillins
Class C antibiotics (pregnancy)
Risk?
Fluroroquinolones, Trimethoprim
Birth defects
Class D antibiotics (pregnancy)
Risk?
Tetracyclines
Fatty liver (mother) hepatotoxicity
Antibiotics contraindicated in children…
Under 8?
Under 18?
Under 18 = Fluroroquinolones (floxacin) (cartilage erosion)
Under 8 = Tetracyclines (bone and teeth deposits) AND Fluoroquinolones
Trimethoprim – why contraindicated in pregnancy?
DHFR inhibitor = deficient folate = BIRTH DEFECTS (months 2 and 3) – CV defects and oral clefts
