Obstetrics

Question 1

Oxytocin: MOA, indications, contraindications, doses

Answer 1

Uterotonic

MOA: Increases intracellular Ca+ levels within uterine smooth muscle cells to induce or strengthen uterine contraction

Dose:
Labor: 0.5-2 mU/min (titrate; max dose 20 mU/min)
Post Partum: 10 units at 20-40 mU/min or 10 IU IM shot
Partial Abortion: 10-20 mU/min

Indications:

• Induction of Labor in the setting of premature rupture of the membranes, isoimmunization, fetal growth restriction, and uteroplacental insufficiency (as in diabetes, preeclampsia, or eclampsia)
• augmentation of dysfunctional (weak) labor
• stimulation of uterine contraction postpartum → prevents hemorrhage
• augmentation of dysfunctional (weak) labor
• stimulation of uterine contraction postpartum → prevents hemorrhage

Contraindications: trauma of the mother or fetus due to forced passage through an incompletely dilated cervix, uterine rupture, and compromised fetal oxygenation due to decreased uterine perfusion

Question 2

Carboprost (Hemabate): Class, MOA, Dose, Indication, Contraindication

Answer 2

Class: PGE2 receptor agonist

MOA: Induces uterine contractions / expulsion of the placenta

Dose: Post Partum Hemorrhage: 250 mcg IM
- repeat q15min - 2000mcg max

Indications: Post Partum Hemorrhage

Contraindications/side effects: Promotes Bronchospasm
Increases CO/PVR/PAP/N&V

Question 3

Methylergonovine (Methergine): Class, MOA, Dose, Indication, Contraindication

Answer 3

ClassAlpha-adrenergic, serotonin, and dopaminergic agonist

MOA: Prevent/control post-partum hemorrhage via vasoconstriction and highly specific contraction of uterine smooth muscle

Dose: IV/IM: 200 mcg
- may be repeated Q2-4 hrs up to 5 doses

Indication: Post Partum Hemorrhage

Contraindication: Use with caution in pts with PVD, HTN, CAD
Can cause severe HTN, convulsions, stroke, retinal detachment and Pulm edema

Question 4

Why do we give Magnesium Sulfate to pre-eclamptic patients?

Answer 4

Prevention of seizures associated with pre-eclampsia

Question 5

What utertonic agent is contraindicated in patients with HTN?

Answer 5

Methergine

Question 6

How do tocolytic agents impact anesthesia?

Answer 6

Potentiate both NMBA and anesthetic gases, in crash C/S should use less of both of agents (may not need to use NMBA)