TRH's uterine drugs; 4.8

Question 1

What category of drugs is used to either promote labor or to limit bleeding post-labor?

Answer 1

Oxytocics

Question 2

What are three types of oxytocics?

Answer 2

Oxytocin analogs
Prostaglandins
Ergots

Question 3

Oxytocin analogs obviously work on oxytocin receptors (OTRs). What kind of receptor is this? Where are they in the body?

Answer 3

OTRs are Gq receptors

OTRs are present in myoepithelial cells of mammary gland, pregnant myometrium, and CNS

Question 4

What is required for OTRs to function?

Answer 4

Well, clearly oxytocin, but also Mg++ and cholesterol

Question 5

What is the pharmacology utility of oxytocin analogs?

Answer 5

Uterine contractions
Milk let-down
Antidiuretic and vasoactive at high concentrations (ADH-like)

Question 6

What kind of hormone is oxytocin (and its analogs)? What does this mean about administration?

Answer 6

Oxytocin is peptide hormone…so it canNOT be given orally

Question 7

What enzyme of uterine/placental origin degrades oxytocin?

Answer 7

Oxytocinase…causes oxytocin (and analogs?) to be broken faster at pregnancy term

Question 8

What is the name of the synthetic oxytocin?

Answer 8

Pitocin

Question 9

When is pitocin used?

Answer 9

Drug of choice for labor induction
Milk let-down postpartum
Stimulation of uterine motility postpartum to reduce bleeding

Question 10

When shouldn’t pitocin be used?

Answer 10

As an abortifacient
When there is cephalo-pelvic disproportion
Hypertonic uterine contractions
Use in women w/ previous C-sections (increased risk of uterine rupture)

Question 11

What is the role of prostaglandins during labor?

Answer 11

Uterine contractions and hyperalgesia

Question 12

What is the hormonal control of prostaglandins (PGs)?

Answer 12

Progesterone → decreased PGs

Estrogen → increased PGs

Question 13

What are three examples of PROSTaglandin drugs?

Answer 13

DinoPROSTone
CarboPROST
MisoPROSTol

Question 14

Which PG drugs mimic PGE2?

Answer 14

Dinoprostone

Misoprostol

Question 15

What PG does carboprost mimic?

Answer 15

PGF2α

Question 16

How are PGs used?

Answer 16

Basically, they cause the cervix to ripen/dilate and for delivery of whatever is in the uterus (fetus/baby/mole)

Question 17

How is carboprost given?

Answer 17

Carboprost is given IM

Question 18

How is misoprostol given? What is typically given with it?

Answer 18

Misoprostol is given vaginally or orally with mifepristone (a progesterone receptor antagonist)

Question 19

How do ergots work?

Answer 19

Ergots are potent smooth muscle stimulators

Question 20

How are ergots obtained?

Answer 20

From a fungus that grows on rye

Question 21

What are examples of ergots?

Answer 21

Ergonovine
Ergotamine
LSD

Question 22

Which ergot is used to control postpartum bleeding by causing uterine contraction?

Answer 22

Ergonovine

Question 23

What is ergotamine used for?

Answer 23

Ergotamine is used for migraine headaches…it causes blood vessels to contract

Question 24

What is LSD used for?

Answer 24

To smell colors and taste music

Question 25

What are tocolytics used for?

Answer 25

Tocolytics reduce uterine contractions

Question 26

What are examples of tocolytics?

Answer 26

β2 agonist MgSO4 OTR antagonist NSAID

Question 27

What do β2 agonist do?

Answer 27

Activates adenylyl cyclase → increased cAMP → activated PKA → Inhibited MLCK → NO phosphorylated myosin → NO contraction

Question 28

What are the potential side effects of β2 agonist?

Answer 28

Elevate maternal BP and cause pulmonary edema Cause hyperglycemia Increase oxygen demand → can precipitate an MI

Question 29

Which β2 agonists are used to reduce uterine contractility?

Answer 29

Terbutaline | Ritodrine

Question 30

How does magnesium sulfate cause smooth muscle relaxation?

Answer 30

Mg++ competes with Ca++

Question 31

How is MgSO4 administered? What is it used to prevent?

Answer 31

MgSO4 is given IV to prevent seizures associated with eclampsia

Question 32

What is an example of an OTR antagonist?

Answer 32

AtOsiBAN | O for oxytocin...Oxytocin is BANned

Question 33

When is atosiban used?

Answer 33

Atosiban delays labor

Question 34

What is a key side effect of atosiban?

Answer 34

Increased fetal mortality

Question 35

Which NSAID is used to reduce uterine contractility?

Answer 35

Indomethacin