Block 2

Question 1

Oxytocin

Answer 1

• uterotonic agent used for IOL, augmentation, and postpartum hemorrhage - short duration, so best given in IV drip w/ RN monitoring - SE’s: water retention, uterine rupture - contraindicated if fetal intolerance w/ ctxns

Question 2

Ergonovine

Answer 2

-uterotonic agent used to prevent/tx postpartum bleeding - short duration, given IM - SE’s: HTN, vomitting - contradicated in pre-existing HTN, can lead to pre-E

Question 3

Prostaglandin E1/E2

Answer 3

Misoprostol, Cytotec, Dinoprostone, Cervidil, or Prostin E2 - uterotonic agent used for IOL, augmentation, and to tx PP bleeding - lasts hours, can be given PO or vaginally - SE’s: nausea, diarrhea, fever, *clinically may be confused with infection - contraindicated in renal/liver failure and in asthmatics

Question 4

B2 adrenergic agonists

Answer 4

Terbutaline and Ritodrine - increase cAMP to phosphorylate myosin light chain kinase (MLCK) - effective in stopping ctxns 48 hrs, but does not decrease overall rate of PTB - side effects: cardiac arrhythmias, pulmonary edema, tachycardia, fetal tachycardia - Given sub-q mostly, but also IV or PO

Question 5

Magnesium Sulfate

Answer 5

MgSO4; off-label tocolytic; competes with Ca2+ for entry into myometrial cells through vg-Ca2+ ch - Given IV -SE’s: flushing, HA, diplopia, pulmonary edema

Question 6

Ca2+ blocker

Answer 6

Nifedipine; blocks uptake of intramyometrial Ca2+ by myometrial cells, used as off-label tocolytic; - stops ctxn for 48-72 hrs - works just as well as beta-agonist and MgSO4 with better safety profile - SE’s: hypotension and HA - Can be given PO an short-acting or long-acting preps

Question 7

Prostaglandin Inhibitors

Answer 7

Indomethacin; prostaglandin synthesis inhibitor (COX 1/2 system), first tocolytic introduced in 1970’s - Few maternal side effects, but serious SE’s for baby: constricts ductus arteriosus, oligohydramnios - Contraindicated beyond 30-32 wks GA

Question 8

Oxytocin Receptor Antagonist

Answer 8

Atosiban (Tractocile, Antocin) - widely used in Europe; - competes with oxytocin for receptor in myometrium; tocolytic - at least as effective as beta-agonists with better safety profile and tolerability - IV admin, new generation are oral forms.

Question 9

Answer 9

Answer: B

Question 10

Answer 10

Answer: C

Question 11

Answer 11

Answer: C

Question 12

Answer 12

Answer: B

Question 13

Answer 13

Answer: B

Question 14

Answer 14

Answer: TRUE

Should never exceed adult dosing because of risk of toxicity

Question 15

Answer 15

Answer: B (increased)

Question 16

Answer 16

Answer: A

Always calculate dose in mg/kg and avoid unnecessary decimal points

Question 17

Answer 17

Answer: all of the above