Oxytocic And Tocolytics

Question 1

As the pregnancy gets closer to parturition, what hormonal shift happens?

Answer 1

Shifts from progesterone > estradiol dominance to estradiol > progesterone dominance

Question 2

What effect does progesterone have on the pregnancy?

Answer 2

Causes hyperpolarization of myometrial cells (preventing contractions); decreases adrenergic receptors, inhibits oxytocin synthesis, inhibits estrogen receptor synthesis; promotes storage of prostaglandin synthesizing enzymes

Question 3

What effect does progesterone have on the adrenergic of the uterus?

Answer 3

Decreases adrenergic receptors

Question 4

Prior to parturition, what hormone inhibits synthesis of oxytocin receptors and estrogen receptors?

Answer 4

Progesterone

Question 5

When closer to parturition and the hormones shift to estradiol > progesterone, what effect does this have on the uterus?

Answer 5

Promotes uterine contractility, increases oxytocin receptors, promotes cervical ripening, increases local prostaglandins release from the placenta (which cause myometrial contractions)

Question 6

What effect do local prostaglandins released from the placenta have on the uterus?

Answer 6

Causes myometrial contractions

Question 7

What prostaglandins predominate in reproduction?

Answer 7

PGF2 and PGE2

Question 8

What is responsible for the mild Braxton Hicks contractions during pregnancy?

Answer 8

PGF2 and PGE2

Question 9

What produces the prostaglandins important for contractions during parturition?

Answer 9

The placental unit

Question 10

What is the function of oxytocin?

Answer 10

Induces smooth muscle contraction - important for myoepithelial cells in breast and myometrium in uterus

Question 11

What do tocolytics do to the pregnancy?

Answer 11

Maintain pregnancy

Question 12

What do oxcytocics do to pregnancy?

Answer 12

Promote labor

Question 13

Where is oxytocin synthesized?

Answer 13

Paraventricular and supraoptic nuclei of the hypothalamus

Question 14

What is neurophysin?

Answer 14

Oxytocin protein carrier protein

Question 15

What kind of receptors are oxytocin receptors?

Answer 15

Gq - coupled to PLC

Question 16

How is oxytocin administered?

Answer 16

Parenteral, sublingual, nasal; not orally

Question 17

What is the drug of choice for labor induction?

Answer 17

Pitocin

Question 18

What is Pitocin?

Answer 18

Synthetic oxytocin

Question 19

What are contraindications of Pitocin?

Answer 19

Not intended as abortifacient; large baby; hypertonic uterine contractions; previous C sections

Question 20

What prostaglandin contracts the uterus and produces hyperalgesia?

Answer 20

PGE2

Question 21

What are the effects of PGE2 in regards to pregnancy/labor?

Answer 21

Contracts uterus; produces hyperalgesia; promotes softening of the cervix

Question 22

PGER is coupled to what?

Answer 22

Gi

Question 23

PGF2 causes what effects in regards to labor/pregnancy?

Answer 23

Causes uterine contractions

Question 24

PGFR is coupled to what?

Answer 24

Gq - stimulates IP3

Question 25

What effects do prostaglandins have on pregnancy/labor?

Answer 25

Induces local myometrial contractions; promotes cervical ripening prior to delivery

Question 26

What effect do prostaglandins have on the cervix?

Answer 26

Ripening - softening, thinning, dilating

Question 27

What is indomethacin?

Answer 27

NSAID - inhibits COX and therefore prostagladin synthesis

Question 28

What is Indomethicin used for in pregnancy/labor?

Answer 28

Reduces uterine contractions and cervical ripening

Question 29

What is dinoprostone?

Answer 29

Natural PGE

Question 30

What is misoprostol?

Answer 30

Synthetic PGE

Question 31

What is dinoprost?

Answer 31

PGF2 alpha

Question 32

What is Carboprost?

Answer 32

PGF2 alpha used i.m.

Question 33

What can misoprostol be used for?

Answer 33

Ripen (dilate) cervix for labor; abortifacient

Question 34

What can carboprost be used for?

Answer 34

Used in any trimester as an abortifaceint or to induce labor

Question 35

What can dinoprostone be used in treatment of?

Answer 35

Hydatidiform mole

Question 36

What is ergonovine? What is its effect?

Answer 36

It is an ergot; causes contraction of the uterus

Question 37

What is ergometrine? What does is do?

Answer 37

Ergot; causes contraction of uterus

Question 38

What are ergots used for medically?

Answer 38

Control postpartum bleeding

Question 39

What receptors do ergots work on?

Answer 39

Alpha adrenergic, dopaminergic, and 5-HT2 receptors

Question 40

What is ergotamine? Use?

Answer 40

Ergot; used in migraines for its contraction of blood vessels

Question 41

What can be used to control postpartum bleeding?

Answer 41

Ergots; oxytocics

Question 42

What are tocolytics used for?

Answer 42

Suppress uterine smooth musc contration; suppress premature labor

Question 43

Who is an optimum candidate for tocolytic therapy?

Answer 43

Women in early phase of acute preterm labor, when cervical dilation is not advanced

Question 44

What is terbutaline?

Answer 44

Beta 2 agonist

Question 45

What is nifedipine?

Answer 45

Calcium channel blocker (dihyropyridines)

Question 46

What are the downstream effects of calcium binding calmodulin?

Answer 46

Activates MLCK, which phosphorylates myosin light chain, promoting contraction

Question 47

What are the downstream effects of beta 2 agonists?

Answer 47

Gs - activates AC and increases cAMP; cAMP activates protein kinase A which inhibits MLCK (decreasing smooth muscle contraction)

Question 48

During what week is terbutaline used in pregnancy?

Answer 48

After week 20

Question 49

What effect does magnesium sulfate have on uterine contractions?

Answer 49

Inhibits them by competing with calcium; causes smooth muscle relaxation

Question 50

What is atosiban?

Answer 50

Oxytocin receptor antagonist

Question 51

What are the concerns with the use of atosiban?

Answer 51

Increased fetal mortality

Question 52

What NSAID is used as a tocolytic? What is its mechanism?

Answer 52

Indomethacin; blocks cox and inhibits prostaglandin formation

Question 53

What are the PGE agonists used as oxytocics?

Answer 53

Misoprostal and dinoprostone

Question 54

What are the PGF2 alpha agonists used as oxytocics?

Answer 54

Dinoprost, carboprost

Question 55

What beta 2 agonist is used as a tocolytic?

Answer 55

Terbutaline