Week 4: Reproductive pharmacology: Estrogens and Progestins Flashcards
Antiestrogens: Receptor antagonists
- fulvestrant (full antagonist)
- Tamoxifen (SERMs)
Antiestrogens: aromatase inhibitors
Anastrozole
Antiestrogens: GnRH agonists
Danazol
Antiandrogens: receptor antagonists
Flutamide
Antiandrogens: 5α-reductase inhibitors
Finasteride
Antiandrogens: Synthesis inhibitors
Ketoconazole
Antiandrogens: GnRH agonists
Combined oral contraceptives
Hypogonadism in girls and women Drugs
Estrogen component:
- Conjugated estrogens
- Ethinyl estradiol
- Estrone
- Estriol
Progestin component:
- Progesterone
- Medroxyprogesterone acetate
Drugs for oral hormonal contraceptive
Combined
- Ethinyl estradiol or mestranol + a progestin
Progestin-only
- Norethindrone or Norgestrel
Drugs for parenteral contraceptive
- Medroxyprogesterone as a depot IM injection
- Ethinyl estradiol and norelgestromin as a weekly patch
- Ethinyl estradiol and etonogestrel as a monthly vaginal ring
- 1-Norgestrel as an intrauterine device (IUD)
- Etonogestrel as a subcutaneous implant
Drugs for Postcoital contraceptive
- 1-Norgestrel
- combined oral contraceptive
Drugs for Intractable dysmenorrhea or uterine bleeding
- Conjugated estrogens
- ethinyl estradiol
- oral contraceptive
- GnRH agonist
- Depot injection of medroxypreogesterone acetate
Drugs for infertility
- Clomiphene
- hMG and hCG
- GnRH analogs
- Progesterone
- Bromocriptine
Drugs for Abortifacient
- Mifepristone (RU 486) and misoprostol
Drugs for endometriosis
- Oral contraceptive
- depot injection of medroxyprogesterone acetate
- GnRH agonist
- Danazol
Drugs for breast cancer
- Tamoxifen
- aromatase inhibitors (eg anastrozole)
Drugs for osteoporosis in postmenopausal women
- Conjugated estrogens
- estradiol
- raloxifene
Drugs for hypogonadism in boys, men or used as replacement therapy
- Testosterone enanthate or cypionate
- methyltestosterone
- Fluoxymesterone
- Testosterone (patch)
Drugs for Anabolic Protein Synthesis
- Oxandrolene
- Stanozolol
Drugs for Prostate hyperplasia (benign)
Finasteride
Drugs for prostate carcinoma
- GnRH agonist
- GnRH receptor antagonist
- Androgen receptor antagonist (eg flutamide)
Drugs for Hirsutism
- Combined oral contraceptive
- Spironolactone
- Flutamide
- GnRH agonist
Clinical uses of estrogens
- Primary hypogonadism in young females
- Hormone replacement therapy (HRT)
- Premature ovarian failure
- Postmenopausal
- Post-surgical removal of ovaries
- Suppress ovulation in patients with intractable dysmenorrhea
- Suppression of ovarian function is used in the treatment of hirsutism and amenorrhea due to excesive secretion of androgens by the ovary
- Components of hormonal contraceptives
Specific estrogen toxicity in primary hypogonasim
in hypogonadal girls, dosage must be adjusted carefully to prevent premature closure of epiphyses of the long bones resulting in short stature
Specific estrogen toxicities when used as HRT
- Estrogen increases the risk of endometrial cancer
- this effect is prevented by combining estrogen with a progestin
How is the risk of endometrial cancer through estrogen HRT reduced?
By combining the estrogen with a progestin
What are the dose-dependent toxicities of estrogen?
- nausea
- breast tenderness
- increased risk of migraine headache
- thromboembolic events (eg deep vein thrombosis (DVT))
- Gallbladder disease
- Hypertriglyceridemia
- hypertension
Antiestrogens: Receptor antagonists
Full antagonists
- Fulvestrant
Selective-estrogen receptor antagonists
- Tamoxifen
Antiestrogens: Aromatase inhibitors
Anastrozole
Antiestrogens: others
- GnRH agonists
- Danazol
What is Fulvestrant?
A pure full estrogen receptor antagonist (in all tissues)
Fulvestrant clinical uses
used in the treatment of women with breast cancer that have developed resistance to tamoxifen
SERM AKA
Selective Estrogen Receptor Modulators (SERMs)
What are SERMs?
- SERMs are mixed estrogen agonists that have estrogen agonist effects in some tissues and act as partial agonists or antagonists of estrogen in other tissues
- Interactions of the estrogen receptor with various coregulators appear to be responsible for some of the tissue-specific effects of SERMs
What is Tamoxifen?
a Selective Estrogen Receptor Modulator (SERM)
has mixed agonist and antagnoist effects in various tissues
Tamoxifen clinical uses
- effective in the treatment of hormone-responsive breast cancer where it acts as an antagonist
- Prophylactic treatment of tamoxifen reduces the incidence of breast cancer in women who are at very high risk
- Has greater agonist effect in bone and thus prevents osteoporosis in postmenopausal women
Tamoxifen side effects
- Works as an agonist on endometrial receptors and thus promotes endometrial hyperplasia and increases the risk of endometrial cancer (agonist effect)
- Causes hot flushes (antagonist effect)
- increases the risk of venous thrombosis (agonist effect)
What is Clomiphene?
A Selective Estrogen Receptor Modulator (SERM) + is a nonsteroidal compound with tissue-specific actions
has mixed agonist and antagonist effects on the estrogen receptors of various tissues (tissue-dependent)
Clomiphene clinical uses & mechanism
- used to induce ovulation in anovulatory women who wish to become pregnant
- By selectively blocking estrogen receptors in the pituitary, clomiphene reduces negative-feedback and increases FSH and LH output
- This increase in gonadotropins stimulates ovulation
Antiestrogens: Aromatase inhibitors
Anastrozole
What is anastrozole?
A non-steroidal competitive aromatase inhibitor
Anastrozole related compounds
Letrozole
What is Letrozole
related to anastrozole
A non-steroidal competitive aromatase inhibitor
Anastrozole clinical uses
used in the treatment of breast cancer
What is Exemestane?
an irreversible aromatase inhibitor unlike Anastrozole which is a competitive inhibitor
Anastrozole & related compounds MOA
- nonsteroidal competitive inhibitors of Aromatase
- Aromatase is the enzyme required for the last step in estrogen synthesis
- Exemestane is an irreversible aromatase inhibitor
What is Danazol?
Danazol inhibits several cytochrome P450 enzymes involved in gonadal steroid synthesis and is a weak partial agonist of progestin, androgen and glucocorticoid receptors
Danazol clinical uses
Sometimes used in the treatment of endometriosis and fibrocystic disease of the breast
What are GnRH analogs?
The cotinuous administration of GnRH agonists (eg Leuprolide) suppresses and thereby inhibits ovarian production of estrogens and progesterone
Examples of GnRH analogs
Leuprolide
Clinical uses in women of GnRH analogs
what is an example of a GnRH analog?
*eg Leuprolide*
GnRH agonists are used in combination with other agents in controlled ovarian hyperstimulation and are also used for treatment of precocious puberty in children and short term (<6 months) treatment of endometriosis and uterine fibroids in women
Clinical uses of Progestins
- Hormonal contraception, either alone or in combination with an estrogen
- the presence of progestin reduces estrogen-induced endometrial cancer
- Postmenopausal hormone replacement therapy, in combination with Estrogen
- Progesterone is used in assisted reproductive technology methods to promote and maintain pregnancy
- Long-term ovarian suppression for other purposes
What is the toxicity of Progestins?
toxicity of progestins is low, but, they may;
- increase blood pressure
- decrease HDL
- Long-term use of high doses in premenopausal women is associated with a reversible decrease in bone density (a secondary effect of ovarian suppression and decreased ovarian production of Estrogen)
- delayed resumption of ovulation after termination of therapy
What is Mifepristone?
an orally active steroid antagonist of progesterone and glucocorticoids
Mifepristone clinical uses
- Major use is as an abortifacient in early pregnancy (up to 49 days after the last menstrual period)
- used with the PGE analog Misoprostol to increase uterine contractions
- The combination of Mifepristone and Misoprostol achieves a complete abortion in >90% of early pregnancies
Pure Mifepristone toxicities
- The most common complication is failure to induce a complete abortion
- Contraindicated during chronic glucocorticoid therapy due to anti-glucocorticoid activity
Mifepristone + Misoprostol side effects
- Most common complication is failure to induce a complete abortion
- Primarily due to misoprostol = NVD
- Rarely, patients who use Mifepristone + Misoprostol for medical abortion have experienced serious infection, sepsis and even death due to unusual infection (eg Clostridium sordelli)
- Contraindicated during chronic glucocorticoid therapy due to anti-glucocorticoid therapy due to synergystic anti-glucocorticoid activity
Mifeprestone + Misoprostol contraindications
- Contraindicated during chronic glucocorticoid therapy due to anti-glucocorticoid therapy due to synergystic anti-glucocorticoid activity
- Rarely, patients who use Mifepristone + Misoprostol for medical abortion have experienced serious infection, sepsis and even death due to unusual infection (eg Clostridium sordelli)
Mifepristone MOA in Pregnancy Termination
- Causes decidual breakdown, blastocyst detachment and decreased hCG production
- Decreased hCG results in decreased progesterone secretion from the corpus luteum, causing futher decidual breakdown
- Decreased progesterone production and receptor blockade leads to increased prostaglandin levels
- causes
- myometrial contractions
- Cervical softening
- causes
Describe the menstrual cycle and the hormone levels during the cycle

What are the various preparations of Oral Contraceptives?
two types of preparations
- Estrogen + Progestin combination
- continuous progestin w/o co-administration of an estrogen
What is the MOA of Oral contraceptives?
Primary
- Prevent ovulation by suppressing LH and FSH secretion by the anterior pituitary: *Negative feedback*
- Estrogen acts directly on the anterior pituitary on the anterior pituitary to decrease FSH and LH secretion
- Progestins act on the hypothalamus to decrease GnRH release, which reduces FSH and LH secretion by the anterior pituitary
Secondary
- Progesterone thickens cervical mucus, acting as a barrier to sperm
- Reduction in endometrial growth interferes with implantation
- Slowed uterine tubal motility and ova transport reduce fertilization
How do the MOAs of Estrogens and Progestins differ as an Oral Contraceptive?
- Estrogen acts directly on the anterior pituitary on the anterior pituitary to decrease FSH and LH secretion
- Progestins act on the hypothalamus to decrease GnRH release, which reduces FSH and LH secretion by the anterior pituitary
Progesterone also thickens the cervical mucus to act as a sperm barrier and also inhibits the endometrium growth and slowed tubal motility resulting in reduced implantation and fertilization respectively but in the wrong order fertiliization would occur first
What are the types of combination agents?
- Monophasic
- Biphasic
- Triphasic
These attempt to lower total steroid dose and mimic the menstrual cycle
21 vs 28 day packs (inert pills during withdrawal bleed)
Estrogen: Ethinyl estradiol 20-35 ug
Progestin dose varies due to differences in potency
“perfect use” has an effectiveness of 99%
What is the effectiveness in preventing pregnancy for “perfect use” of Combination Oral Contraceptives?
“perfect use” effectiveness is 99%
Adverse effects of Combination Oral contraceptives?
- Incidence of serious adverse effects associated w/ COCs is lower than the incidence of complications associated with pregnancy
Major adverse effects
- VTE (3-4 fold ↑ compared to those not taking OCs)
- HTN
- Lipid effects (↑TG, ↑ cholesterol, ↑ or no change HDL, ↓ LDL)
- MI
- CV risks are greatest in smoker > 35 years old
Minor-to-moderate side effects
- nausea
- edema
- HA
- worsening migraines
- breakthrough bleeding
- increased skin pigmentation
- ↑ skin pigmentation
- increased incidence of vaginal infections
- amenorrhea
Describe the risk of cancer associated with COCs

Non-contraceptive benefits of COCs
- 50% ↓ in endometrial cancer risk, benefit lasting 15 years after the COCs are stopped
- ↓ risk of ovarian cancer
- ↓ ovarian cysts and fibrocystic disease
- ↓ iron-deficiency anemia
- ↓ dysmenorrhea and endometriosis side effects
- ↓ ectopic pregnancies and pelvic inflammatory disease
COCs effect on breast feeding
- Estrogens suppress lactation
- low dose OCs produce minimal effects on milk production, Low concentrations of OCs are found in breast milk
- existing low-quality evidence suggests that combined oral contraceptives may reduce the volume of breastmilk but not affect the growth of infants
Drug interactions of COCs
- Antibiotics may alter enterohepatic cycling of oral contraceptive metabolites
- Multiple pharmacokinetic interactions CYP- and uridine 5’-diphosphate glucuronosyltransferase (UGT) catalyzed reactions
- Ethinyl estradiol is metabolized by CYP3A4 and CYP2C9
- UGT1A1 is the predominant UGT for Ethinyl Estradiol
- Most progestogens are substrated for CYP3A4 and some metabolites require glucuronidation
Progestin-only OCs AKA
often called “minipill”
Progestin-only OCs MOA
- GnRH suppression through negative feedback on the hypothalamus is the major mechanism
- increases the viscosity of cervical mucus, acting as a physical barrier to sperm penetration
- Rapid first-pass metabolism
- Same dose taken daily (no inert pills)
Progestin-only OCs “perfect use” effectiveness
“perfect use” effectiveness for Progestin-only OCs is less than COCs
Progestin-only OCs Adverse effects
- Breakthrough bleeding is the most common adverse effect (up to 25% of patients)
- No evidence of increased VTE
- May cause more acne
Properties of progestational agents

What are the failure rates for Oral contraceptives vs condoms?

Transdermal contraception Examples
Ortho Evra patch
MOA of Transdermal contraception
- Ortho Evra patch
- Combination estrogen and progestin
- Ethinyl estradiol and norelgestromin
- apply to buttock, abdomen, upper arm or torso
- Changed weekly x3 weeks, then 1 week off for withdrawal bleed
Transdermal contraception side effects
- some sensitivites to adhesive have been reported
- concerns for higher estrogen levels due to no first-pass effect, ↑ risk of VTE
Examples of the Contraceptive ring
Nuvaring
MOA of Contraceptive ring
Combination of estrogen and progestin
- Ethinyl estradiol and etonogestrel
- 3 weeks in place followed by 1 week off for withdrawal bleed
- transmucosal absorption
Contraceptive ring side effects
- issues with expulsion during sexual intercourse
- safety profile appears to be the same as with other combined hormonal contraceptives
Examples of Contraceptive Subcutaneous implant
Etonogestrel (Nexplanon)
MOA of Contraceptive Subcutaneous implant
Progesterone-only
- Etonogestrel is a progestin
- Lasts 3 years
Contraceptive Subcutaneous implant side effects
possible side effects
- HA
- weight gain
- mood changes
- acne
- local infection
- difficult removal
Irregular vaginal bleeding is the norm and pattern is unpredictable
Use with caution in those w/ history or predisposition to VTE
Contraceptive Subcutaneous implant
Examples of Contraceptive injection
Medroxyprogesterone acetate (Depo-Provera)
MOA of Contraceptive injection
- Medroxyprogesterone acetate (Depo-Provera)
- Given IM
- Lasts 12 weeks
Contraceptive injection side effects
- Causes irregular vaginal bleeding and eventual amenorrhea
Other possible side effects
- HA
- Mood changes
- Weight gain
- ↓ HDL
- ↑LDL
- ↓ bone density
- return to fertility can be delayed
Contraindicated in those w/ history or predispotion to VTE
Contraceptive injection Contraindications
Contraindicated in those w/ history or predisposition to VTE
Examples of hormone-containing intrauterine devices
Levonorgestrel (Mirena)
MOA hormone-containing intrauterine devices
- Levonorgestrel (Mirena)
- 5 year effectiveness
- Local progestin concentration ~1000x higher than systemic levels
- Thickening of cervical mucus to prevent sperm penetration
- Inhibits ovulation in some cases
- Reduced endometrial growth
- expect spotting for up to 3 months, then light and irregular menses or amenorrhea
What is Emergency Contraception?
Refers to the use of any drug or device to prevent pregnancy after unprotected intercourse or when contraception has failed
Types of progestin-only Emergency contraception
Levonorgestrel as Plan B or Plan B one-step
progestin-only Emergency contraception MOA
Levonorgestrel plan B
- Most effective within 72 hours of unprotected sex
- prevention of ovulation, blocking implantation, increased cervical mucus viscosity
- available without prescription
MOA of Selective progesterone receptor modulators as emergency contraception
- 30 mg single dose
- inhibits ovulation via inhibition of LH release
- May block implantation of fertilized egg (uncertain)
- Effective up to 120 hours after unprotected sex
- Available by perscription only
- May be more efficacious than levonorgestrel for overweight (BMI >25 kg/m2) women
Selective progesterone receptor modulators as emergency contraception adverse effects
self-limited HA and abdominal pain
Types of Selective progesterone receptor modulators as emergency contraception
Ulipristal acetate (Ella)
Considerations of pericoital use of levonorgestrel
reasonably efficacious and safe
Considerations of Combination estrogen-progesterone Emergency contraception
- Less effective
- More NV
- Theoretical concerns of VTE
Emergency Contraception hormone-free
Copper IUD (Paragard)
- Most effective: 1% failure rate when inserted up to 5 days after unprotected sex
- Provides 10 years of contraception
- Copper is toxic to sperm
- Copper increases inflammation in the uterus, which reduces sperm viability and reduces endometrial receptivity
CDC Contraception guidelines

Continued CDC Contraception guidelines

Effectiveness of family plannning methods

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Additional info on the effects of estrogens on LDL and HDL

The effects of OCs on serum lipid values

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Drugs for Ovulation induction for infertility
- Clomiphene citrate
- Gonadotropins
- Human chorionic gonadotropin
- Progesterone replacement in progesterone deficient women
- Insulin sensitizers (metformin)
Clomiphene citrate clinical uses
Ovulation induction for infertility
MOA of Clomiphene citrate
- Estrogen antagonist, blocking inhibitory effect on gonadotropin release from pituitary
- Increases gonadotropin secretion (FSH>LH), stimulating ovulation
Adverse effects of Clomiphene citrate
- Ovarian hyperstimulation
- multiple gestation
- ovarian cysts
- HA
- hot flushes
- blurry vision
- luteal phase defect due to inadequate progesterone production
- increased ovarian cancer risk with prolonged use
Drugs for o
Drugs for ectopic pregnancy management
- Methotrexate
MOA of methotrexate for ectopic pregnancy management
- as antimetabolite: folic acid antagonist
- Disrupts rapidly proliferating trophoblast
- Used to treat certain types of cancer (for example gestational trophoblastic disease - choriocarcinoma) Psoriasis, RA
- Can be used to terminate an intrauterine pregnancy, followed by misoprostol to induce uterine contractions, but mostly replaced by mifepristone now
Methotrexate clinical uses
- as antimetabolite: Folic acid antagonist
- Used in medical management of ectopic pregnancy < 3.5 cm, no cardiac activity, hemodynamically stable, can adhere to f/u
- Management is generally outpatient with frequent follow-up of labs and physical exam
- Used to treat certain types of cancer (for example gestational trophoblastic disease = choriocarcinoma), psoriasis, RA
Adverse effects of methotrexate for ectopic pregnancy management
- Liver damage
- lung damage
- damage to the lining of the mouth, stomach or intestines
- Increased risk of lymphoma
- serious or life-threatening skin reactions
- immunosuppression