Pharm 3 Estrogen/Progestin Flashcards
Ovarian-pituitary cycle
- Elevated FSH during 1st half stimulates follicle
- Midcycle estradiol exerts positive feedback, triggers LH surge
- LH surge induces ovulation, stimulates corpus luteum and progesterone production
Pregnancy hormone
hCG (chorionic gonadotorpin) identical to LH, maintains estrogen and progesterone production by maintaining corpus luteum
Hormones interacting with endometrium
- Estrogen mediates proliferation
- Progesterone maintains secretory state
Base molecule for estrodiol/testosterone synthesis
Cholesterol
Hormone replacement therapy
Estradiol undergoes extensive first-pass metabolism, so use conjugated estrogens (estrone sulfate)
-Estrone sulfate-
indication
Conjugated estrogen absorbed in lower gut
-Hormone replacement therapy
-Ethinyl estradiol-
indication
Ethinyl substitution reduces first-pass metabolism, greater oral potency than conjugated estrogens
-Oral contraceptives
-Estradiol cypionate-
Insoluble in water
-Once monthly IM for HRT
-Medroxyprogesterone-
Breast and endometrial cancer
-Oral or IM
-Megestrol-
Endometrial cancer
-Norethindrone-
19-nortestosterone derivative Progestin
-Oral contraceptives
-Desogestrel-
Progesterone for oral contraceptive
-Lowest degree of androgenic activity
Estradiol/Progesterone transport
- Estradiol bound to SHBG (sex hormone binding globulin) high affinity
- Progesterone bound to CBG (corticosteroid binding globulin) with high affinity
- Both bound to albumin with low affinity
Estradiol/Progesterone Metabolism
Hepatic conjugation
- Estradiol -> estrone -> bile -> reabsorbed
- Progesterone -> pregnanediol
Estrogen MOA
Binds to nuclear receptor (homodimer), regulates trasncription
Progestin MOA
Binds to response element similar to that of corticosteroids
Estrogen effects on bone
- Prepubertal growth of long bones
- Pubertal closure of epiphyses
- Post pubertal decreased bone resorption
Estrogen effects on clotting
- Increase clotting factors
- Decrease antithrombin
- Increase platelet adhesiveness
Estrogen effects on lipids
Increase HDL, triglycerides
Decrease LDL
Estrogen effect of sex behavior
-Mediates testosterone’s effect on libido
Estrogen other effects
- Maintain skin and blood vessel integrity
- Increase CBG, TBG, SHBG
- Increase cortisol
- Increase Na and water retention
Progesterone v Estrogen
Antagonize estrogen
- Decrease Na retention
- Decrease HDL
- Increase metabolism
- Downregulate receptors
Progesterone other effects
- Stimulate respiratory center
- Increase insulin, reduce glucose tolerance
- Acne
- Weight gain
Primary hypogonadic impaired development Tx
-Start estrogen at 11-13, add progestin when growht is completed
Hysterectomy HRT
Unopposed estrogen (don’t worry about progesterone)
Other clinical uses for Estrogen
- Ovarian suppression for hyperandrogenism
- Ovulation suppression in dysmenorrhea
- Androgen-dependent prostate cancer (suppress gonadotropin secretion)
Estradiol levels postmenopausal
1/4 that of males
Postmenopausal HRT alleviates (5)
Sleep disturbances Hot flashes Urogenital changes Osteoporosis High cholesterol
HRT contraindications
Liver disease
Breast or other estrogen-dependent cancer
Low dose combination OC
- All use ethinyl estradiol
- Norgestrel for monophasic
- Norethindrone for bi/triphasic
Monophasic v Triphasic
- Triphasic eliminates period for 90 days
- Triphasic reduces total dose of progestin (reduced SE)
OC MOA
Inhibit gonadotropin secretion, suppress ovulation (progestin only blocks ovulation 60-80%)
- Thicken cervical mucus
- Reduce tubal secretion/motility
- Change uterine endometrium
OC mild AE
Breakthrough bleeding
-Tx with higher dose estrogen or different progestin
OC moderate AE
Acne with higher progestin doses
-Nausea, mastalgia, weight gain, headache
OC severe AE
- Thromboembolism (estrogen dependent)
- Myocardial infarction
- Cholestatic jaundice
OC neoplasm risk
Hepatic adenoma
OC contraindications
Impaired liver function, h/o thromboembolic disease, CAD, hyperlipidemia
OC caution with
Migraine, HTN, DM, gallbladder disease
OC drug interactions
- Decreased efficacy with antibiotics that affect GI absorption
- Insulin efficacy reduced by OC
Tx for endometriosis
Medroxyprogesterone Acetate (IM injection every 3 months) -Amenorrhea side effect
-Clomiphene-
Antiestrogen (competitive) reduces negative feedback
-Induces ovulation
-Fulvestrant-
Pure estrogen receptor antagonist
-For treating hormone-responsive metastatic breast cancer in postmenopausal women
-Tamoxifen-
Anti-estrogen on breast
- Pro-estrogen on lipids, bones, endometrium
- Tx perimenopausal symptoms
-Raloxifene-
Anti-estrogen on breast, pro (1/2 strength) on bones
- Tx post-menopausal osteoporosis, BRCA
- No effect on perimenopausal symptoms
-Mifepristone (RU 486)-
MOA
Parent molecule
Effect
Progesterone-R antagonist, glucocorticoid-R antagonist, prostaglandin dehydrogenase inhibitor
- Norethindrone derivative
- Stimulate uterine SM contractility
-Mifepristone-
other use
Glucocorticoid receptor antagonist
-Tx Cushing’s secondary to ectopic ACTH secretion
Abortion regimen
Mifepristone in first 49 days
-Misoprostol (prostaglandin analog) 48 hours later to expel blastocyst