Gonadal Hormone Inhibitors and Uterotonics Flashcards Preview

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Flashcards in Gonadal Hormone Inhibitors and Uterotonics Deck (34)
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1
Q

What do progestins, androgens, and estrogens have in common? (precursor, type of molecule)

A

Lipophillic because their common precursor is cholesterol

2
Q

What is the most potent naturally occurring estrogen?

A

Estradiol

3
Q

Progestins give rise to ______ which give rise to _______

A

Androgens

Estrogens

4
Q

What type of feedback occurs to control the release of GnRH by the hypothalamus?

A

Negative

5
Q

How do 5a-reductase inhibitors work and what are examples?

A

Finasteride (Proscar, Propecia) and Dutasteride (Avodart)

Competitive and selective inhibition of the enzyme 5a-reductase which usually converts testosterone to dihydrotestosterone (a more potent form of testosterone) which then binds to an androgen receptor

6
Q

What are 5a-reductase inhibitors (finasteride and dutasteride) used to treat?

A

BPH and alopecia

7
Q

5a-reductase inhibitors effect which receptors?

A

Type I: skin, liver (dutasteride)

Type II: prostate and scalp(finasteride and also dutasteride)

8
Q

How do aromatase inhibitors work?

A

Inhibits the enzyme aromatase which converts androgen to estrogen.

9
Q

What type of synthesis inhibitors are anastrazole, letrazole, exemestane, and formestane and how do they differ?

A

Aromatase inhibitors
anastrazole, letrazole are competitive inhibitors
exemestane, formestane bind covalently and are irreversible

10
Q

What are aromatase inhibitors used to treat?

A

ER+(estrogen feeding tumors) breast cancer that is hormonally responsive

11
Q

AE of aromatase inhibitors are d/t what and include what?

A

d/t: profound suppression of estrogen action which is a major regulator of bone density
include: increased risk of osteoporosis and fractures

12
Q

What are SERMs?

A

Selective estrogen receptor modulators

They have tissue specific agonist/antagonist activity (mixed)- activity depends on the tissue being acted on

13
Q

What is the the SERM Tamoxifen used to treat but what can it cause?

A

Inhibits growth of estrogen dependent (ER+) breast tumors but can stimulate endometrial cancer

(breast-antag, endometrium- agonist, bone-slight agonist)

14
Q

How is the SERM Raloxifene (Evista) similar to Tamoxifen and how is it different? What is it used to prevent?

A

Also an estrogen antagonist in the breast, but does not stimulate endometrium. It is an agonist in the bone so can be used to delay or prevent osteoporosis

15
Q

What is the SERM Clomiphene (Clomid) used for and how does it work?

A

Used to induce ovulation
Estrogen receptor antagonist(shuts of neg. feedback loop) in the hypothalamus and anterior pit gland increasing GnRH which increases estrogen and ovulation

16
Q

How does the estrogen receptor antagonist, Fulvestrant work and what is it used for?

A

Pure estrogen antagonist
Competitively inhibits estrogen receptors in breast cancer cells (no effects elsewhere)
Used in hormonally responsive (ER+) breast cancer to slow tumor growth

17
Q

What are Flutamide(Eulexin) and Bicalutamide (Cadodex) used to treat and what type of drug are they?

A

Androgen Receptor Antagonists

Used to treat prostate cancer and BPH

18
Q

What is spironolactone used to treat and what type of drug is it?

A

Androgen receptor antagonist

Used to treat hirsutism

19
Q

What type of antagonist is Mifepristone (RU-486) and what is it used for?

A

Progesterone Receptor Antagonist
1st trimester termination of pregnancy
Competitive inhibition of progesterone action causing uterine lining to shed and cervix to soften?

20
Q

What medication is a PGE analogue used for GI protection that also stimulates uterine contractions causing 1st trimester termination of pregnancy(off label)?

A

Misoprostol (Cytotec)

21
Q

How can GnRH agonists and antagonists have the same effect on the body?

A

If given enough GnRH agonist causing negative feedback there will be suppression of FSH and LH release. Both medications can be used to treat cancer of the prostate and breast.

22
Q

What is the purpose of uterotonics?

A

Promote myometrial activity

Stimulate the uterus to contract

23
Q

How can uterotonics be used?(3)

A

To empty the uterus: Labor or termination
Stop Bleeding: Postpartum(immediate or late)
Subinvolution: reduction of uterus post childbirth

24
Q

Why is endogenous or exogenous oxytocin (Pitocin) used?

A

Induce labor
Augment labor
Promotion uterine contractility

25
Q

MOA of oxytoxin (Pitocin) in myometrial cells:

A

Promotes myometrial contraction by increasing free intraceullar Ca++ in myometrial cells
Uterine responsiveness increased from exposure to estrogen (late in preg)
Less oxytocin is needed once labor has begun d/t an upregulation in rc

26
Q

What is oxytocin’s effect on the mammary glands?

A

Causes contraction of mammary glands to let milk down

27
Q

What weak but present action does oxytocin possess when used in large doses and what type of patient would you avoid use in?

A

Weak antidiuretic action d/t ADH like effect (structurally similar to vasopressin)
Caution with use in cardiac, renal disease, or PIH(preg HTN)

28
Q

How is oxytocin administered and its PK?

A

IV continuous gtt
Destroyed in the GI tract (can’t give PO)
Does not cross BBB
Short half life (1-6mins in plasma), effects may last a couple of hours

29
Q

Dinoprostone (Cervadil, Prostin E2, Prepidil) is naturally occurring ______ and is used for what?

A
Prostaglandin E2 (PGE2)
Cervical ripening
30
Q

MOA of Dinoprostone (Cervadil, Prostin E2, Prepidil):

A

Sensitizes myometrium to endogenous or exogenous oxytocin

31
Q

How is Dinoprostone (Cervadil, Prostin E2, Prepidil) administered?

A

Vaginal insert/suppository

Cervical gel

32
Q

What off label use does Misoprostol have?

A

Tablet per vagina can be given for surgical ripening, labor induction, or post-partum hemorrhage.

(Same effect when given orally for GI s/s, category X drug)

33
Q

Lueprolide (Lupron) what type of drug and what is it used for?

A
GnRH agonist (inhibits LH/FSH secretion by increasing GnRH release)
Used for the treatment of breast cancer and prostate cancer

Similar drugs include: Goserelin and Nafarelin

34
Q

GnRH receptor antagonists include:

A

Cetrorelix

Ganirelix