Week 11 - Estrogen and Anti-Estrogens Flashcards
Role of estrogen in the body
- Primary effects are maturation and function of female reproductive system
- Estrogen receptors in: breast, ovaries, uterus, bone, CNS, GI tract, cardiovascular tissue
- Stabilizes endometrium to maintain regular withdrawal bleeding
- Increases bone density
- Results in normal skin and blood vessel structure
- Affects lipids levels
- Reduces bowel motility
- Enhances coagulability of blood
Estrogen formulations
Pill, transdermal, vaginal ring
If there are no contraindications, combined oral contraception may be continued from menarche to menopause
Ethinyl estradiol: indications
- Prevents the release of an egg (ovulation) during your menstrual cycle
- Makes vaginal fluid thicker to prevent sperm from reaching an egg (fertilization)
- Changes the lining of the uterus to prevent attachment of a fertilized egg
Ethinyl estradiol: pharmacokinetics
- Metabolized by the liver
- No significant difference in contraceptive efficacy between dosages
- Start w/ lowest estrogen while maintaining cycle control
- Dose may be increased if breakthrough bleeding occurs
Monophasic, biphasic, triphasic oral contraception therapy
Monophasic: each tablet contains a fixed amount of estrogen and progestin
- Same dose of estrogen and progestin for full cycle
Biphasic: each tablet contains a fixed amont of estrogen while the amount of progestin increases in the second half of the cycle
Triphasic: amount of estrogen may be fixed or variable while the amount of progestin increases in three equal phases
Conditions that carry unacceptable health risks when considering estrogen oral contraceptive therapy
- >35 years and smoking
- Uncontrolled HTN
- VTE
- Current breast cancer
- Cirrhosis
- Migraine w/ aura
- Ischemic heart disease or multiple risk factors
Advantages of oral contraception
- Highly effective
- Rapidly reversible
- Regulates menstrual bleeding
- Decreased menstrual blood loss and dysmenorrhea
- Reduction in risk of ovarian and endometrial cancers
Drug interactions w/ combined oral contraception (COC)
- Metabolism increased by any drug that increases liver enzyme activity
- Anticonvulsants
- Rifampin is the ONLY abx that reduces serum ethinyl estradiol and progestin levels
- Griseofulvin (antifungal) associated w/ contraceptive failure
Estrogen in menopause: indications
- Vasomotor symptoms
- GU symptoms (vaginal dryness, vaginal burning)
- Benefits outweight risk for healthy, symptomatic women who are within 10 years of menopause OR younger than 60 years old and do not have contraindications to treatment
True/False: Long-term use of estrogen during menopause is recommended for prevention of disease
False - NO longer recommended
Estrogen in menopause: formulations
- Oral
- Transdermal
- Topical gels, emulsions, lotions
- Intravaginal creams, tablets, rings
Consider type of estrogen and route of administration, as well as need for progestin
Estrogen in menopause: pharmacokinetics (oral)
- Oral has greater effect on liver d/t first-pass effect
- Oral increases liver production of clotting factors, HDL, triglycerides, and proteins such as sex hormone-binding globulin (SHBG) and thyroxine-binding globulin (TBG)
Estrogen in menopause: pharmacokinetics (transdermal)
- Transdermal associated with lower risk of VTE and stroke
- Less effect on serum lipids compared to comparable oral dose
- Equally effective to oral for preserving bone density
Where are conjugated equine estrogens (CEEs) dervied from?
Pregnant mare’s urine (mostly comprised of estrone)
Where are synthetic conjugated estrogens derived from?
Plant sources (soy, yams)
What is structurally identical (bioidentical) to the main product of a premenopausal ovary?
Micronized 17-beta estradiol
True/False: Esterified estrogens have comparable serum estradiol/estrone levels to conjugated estrogen
True
True/False: Ethinyl estradiol is more potent than others for menopausal hormone therapy (MHT)
True - use in VERY low doses
Types of estrogen: steroidal
Endogenous
- Estradiol
- Estrone
- Estriol
Types of estrogen: non-steroidal
Exogenous
- Phytoestrogens
- Xenoestrogens
- Mycoestrogens
Ethinyl estradiol dosing
Start w/ low dose estrogen unless severe symptoms arise
Dose can be titrated up if symptoms are not completely relieved by low dose
Estrogen in menopause: vaginal therapies
- Commonly used in low doses for vaginal atrophy
- Vasomotor symptoms treated w/ higher doses
- NOT recommended to use higher vaginal estrogen doses in those who need treatment for GU symptoms only
Estrogen in menopause: ADR
- Breast soreness
- HA
- Elevated BP
- Exacerbation of DM (hyperglycemia)
- Cholestasis
- Thromboembolic event
- Endometrial hyperplasia
Menopausal hormone therapy (MHT): contraindications
- History of breast cancer
- CAD
- VTE
- Stroke/TIA
- Active liver disease
- Unexplained vaginal bleeding
- High risk endometrial cancer
