Antenata and perinatal pharmacology

Question 1

drugs to stim fetal lung maturation

Answer 1

• betamethasone

- dexamethasone

Question 2

drugs to induce labor

Answer 2

• oxytocin (pit H)

- Dinoprostone, Misoprostil- PGE analogs

Question 3

drugs to maintain or close a PDA

Answer 3

• maintain- Alprostadil

- close- Indomethacin (NSAIDs)

Question 4

drugs to delay labor

Answer 4

• MgSO4, Nifedipine (Ca channel antagonists)

- salbutamol, terbutaline, ritodrine (B adrenergic R agonists)

Question 5

Antihypertensive drugs for pregnancy

Answer 5

• alphaMethylDOPA (alpha2 R agonist)

- Labetalol (alpha,B R Blocker)

Question 6

pregnancy categories for dugs

Answer 6

• A and B- no risk
• C- risk evident in animal studies
• D- risk evident in human studies
• X- contraindicated (ex- Warfarin)

Question 7

drug used to promote lung maturation

Answer 7

corticosteroids

• betamethasone- drug of choice- 2 doses, 24 hrs apart
• dexamethasone

Question 8

preterm birth- risk of RDS

Answer 8

• surfactant deficient- leads to RDS

- RDS affects 50% of babies born < 32 wks!!

Question 9

Indications for antenatal corticosteroids

Answer 9

• b/w 24-34 wks of gestation with:
• pre-term labor
• antepartum hemorrhage
• conditions requiring C-delivery- pre-eclampsia, HELLP!!!

Question 10

corticosteroid- moa

Answer 10

• GCR binding
• dissociation
• dimerization
• translocation
• transcription of surfactant proteins!! (alveolar type 2 pneumocytes)

Question 11

risks of antenatal corticosteroids, contraindications

Answer 11

• single course- no significant maternal or fetal adverse effects
• contraindications- mother with systemic infection, TB

Question 12

Why cant we just administer cortisol?

Answer 12

placenta metabolizes (inact) cortisol!!
-11B-HSD2 in placenta- converts cortisol to cortisone

Question 13

physiology of labor

Answer 13

• estrogen- induce oxytocin Rs on uterus
• stretch N impulse- stim release of oxytocin (post pit)
• oxytocin:
• uterine contraction
• placenta- prod PGF2alpha- uterine contraction (and + feedback)

Question 14

PGfalpha- made how

Answer 14

-COX-1

Question 15

drug for cervical ripening and uterine contraction

Answer 15

• Dinoprostone (PGE2)- easily removed if uterine hyperstim occurs
• Misoprostol

Question 16

Prostaglandins- moa

Answer 16

• PGE2- EP Rs
• PGF2alpha- FP Rs
• dilate the cervix, contract the uterus
• deficit of PGs- delayed birth
• excess of PGs- premature labor, birth

Question 17

labor induction- drug

Answer 17

oxytocin

-once cervix is ripe!!

Question 18

Oxytocin challenge test

Answer 18

• controlled stress test to test fetal viability!!!

- provokes contractions- follow fetal heart rate

Question 19

drugs to delay labor

Answer 19

Tocolytic drugs

• B R agonist
• inhibit COX-1
• CA channel antagonist
• competition at Ca channels
• oxytocin R antagonist

Question 20

B R agonist- drugs, SE’s

Answer 20

(relax uterine smooth m)

• Ritodrine
• Salbutamol
• Terbutaline
• hypokalemia, hyperglycemia

Question 21

inhibits uterine COX-1- drug, SE’s

Answer 21

(blocks PGF2alpha and PGE2 formation)

• indomethacin (NSAIDs)
• 2nd trimester only!!
• use at term risks premature in utero closure of ductus arteriosus- fetus
• bleeding risk, ulcer- mother

Question 22

Ca channel antagonist- drug, SE’s

Answer 22

(relax uterine smooth m)

• nifedipine
• dizziness, hypotension- mother

Question 23

competition at Ca channels- drug, SE’s

Answer 23

• MgSO4

- MG- contraindicated

Question 24

oxytocin R antagonist- drug

Answer 24

-atosiban

Question 25

Tocolytic drugs- how long is long enough?

Answer 25

-useful to delay delivery for hrs/days (not to delay indefinitely!!)

Question 26

used to protect against seziures assoc with pre-eclampsia and HELLP syndrome

Answer 26

-MgSO4

Question 27

indomethacin- indicated when?

Answer 27

second trimester of pregnancy

Question 28

ifedipine- use with caution when?

Answer 28

-used with caution in pts with compromised CV condition at risk of pulm edema and cardiac failure

Question 29

selective B2 R agonists- use

Answer 29

- SE's of hypokalemia, hyperglycemia | - leads to discontinuation and choosing alternative tocolytic drugs

Question 30

NSAID use- risks assoc in 3rd trimester

Answer 30

- maternal- prolongation of labor, postpartum hemorrhage | - fetal- intrauterine closure of ductus arteriosus

Question 31

ductus arteriosus- what happens at birth

Answer 31

- birth provokes closure of DA via metabolic inact of PGE2 in lung - maturation of neonatal lung- metabolizes PGE2

Question 32

drug to keep PDA in utero- indication

Answer 32

Endogenous PGE1- alprostadil | -pre-term infants with congenital heart defects

Question 33

Alprostadil- indication

Answer 33

(PGE1) | -maintains a PDA in congenital heart disorders

Question 34

Alprostadil- complications

Answer 34

-pyrexia

Question 35

PDA- in who

Answer 35

premature infants

Question 36

drugs to close ductus arteriosus

Answer 36

NSAIDS- indomethacin (COX inhibitors) | -less PGE2- closure

Question 37

Indomethacin- indications

Answer 37

- premature infants!!- close DA | - not effective for PDA in full term baby!!!

Question 38

complications of NSAIDs in infants

Answer 38

-inhibit COX-1/2- deficit of PG2- renal vasoconstriction- Na and H2O retention, reduced creatinine clearance, mild HTN

Question 39

HTN in pregnancy- drugs

Answer 39

-alpha-methyldopa -labetalol (oral)

Question 40

Methyldopa- moa

Answer 40

centrally acting - converted to alpha-methylnorepinephrine- stim alpha2 Rs- reduces symp outflow from CNS!! - BP falls due to dec in peripheral resistance

Question 41

Adrenergic R blockers

Answer 41

-safety in pregnancy is controversial

Question 42

Labetalol- moa

Answer 42

-alpha and B blocking activity!!!

Question 43

used for acute tx of severe HTN

Answer 43

-IV hydralazine