Contraception: Cook and Phillips Flashcards
What is the main function of oxytocics, and what is their clinical utility?
Main function: induce uterine contraction
Clinical uses:
- induce labor (in case of premature membrane rupture, fetal growth restriction, uteroplacental insufficiency, or pre-eclampsia/eclampsia)
- control post-partum uterine hemorrhage
- induce uterine contraction after C-section or during uterine surgery
- induce therapeutic abortion
What is the main function of tocolytics, and what is their clinical utility?
Main function: suppress labor or uterine contractions
Clinical utility:
- delay or prevent premature parturition
- briefly slow/arrest delivery for therapeutic measures (such as to give GCs to increase surfactant production)
What are the therapeutic uses of estrogens and progestins?
- ->Estrogens (Es):
1. Prostate cancer therapy - synthetic nonsteroidal Es (DES, clorotrianisene)
2. Breast cancer therapy - SERMs are useful for blocking E stimulation of cancer growth - Can’t give native estrogens orally - first-pass met; synthetic Es avoid this effect
- ->Estrogens (Es) AND Progestins (Ps):
- fertility control (E+P/P = “the pill”; “the morning after pill”; Anti-progestin = “the abortion pill”)
- hormone replacement therapy - menopause (E), osteoporosis (E), ovarian failure (E+P)
- dysfunctional uterine bleeding - irregular menses (P or E)
What is the difference between SERMs and antiestrogens?
- SERMS (Selective Estrogen Receptor Modulators) are drugs whose estrogenic activities are tissue selective; these include tamoxifen, raloxifene.
- Anti-estrogens act on ERs in hypothalamus to block feedback inh. and allow GnRH release which leads to inc. LH/FSH, and then inc. ovulation; these include clomiphene and fulvestrant
How are estrogens, progestins, and related drugs used in birth control?
(Specifically, how do E and P prevent pregnancy, and what forms of administration do they come in?)
In general, administration of combination E (ethinyl estradiol or mestranol) and P (norethindrone, norgestrel, or levonorgestrel) will block LH/FSH release by feedback inhibition.
Forms of administration:
1. Pill = have mostly active pills plus some placebos in a regimen
2. TD patch = 3wks on, 1wk off
3. Vaginal ring = 3wks on, 1wk off; not effective until in place for 7d; rapid return to fertility after removal
Just P: continuous low-dose will blocks ovulation in 60-80% of cycles, impairs sperm transport (thickened mucus), dec. motility and and alters endometrium to impair implantation
Forms of administration:
1. Mini-pill: low dose progestin qd (no placebos) 2. Injectable: usually medroxyprogesterone; injected q3mo, d/c after 2yr, takes 6-12mo to return to fertility
3. Implantable: usually etonogestrel, in upper arm, effective for 3 yrs
4. IUD: levonorgestrel, 5yr limit, fertility restored after removal . Prevents pregnancy by thickening cervical mucus, reversing tubal peristalsis, causes ovulatory dysfunction, thins endometrium so fertilized egg cannot implant.
(*can also be a copper IUD–lasts 15-20yr, Cu is spermicidal)
What are the therapeutic uses of gonadotropins?
Females: FSH and LH are used for anovulatory women or women with hypogonadism.
*Risk of multiple pregnancies (multiple follicles mature and therefore multiple eggs are released in one cycle)
Males: to treat infertility, use androgens first to induce sexual development; then use gonadotropins for when fertility is desired
What are the diagnostic uses of gonadotropins?
- pregnancy tests - use Abs specific for CG beta subunit to qualitatively detect CG in urine
- ovulation time - when LH in urine is high, ovulation occurs 36hrs later; test uses LH-specific Abs
Name the gonadotropins that are used therapeutically to treat infertility.
- Menotropin = FSH+LH, injected IM
- Recombinant FSH = SC injection
- Chorionic gonadotropin = injected IM; binds LH receptor
What are the non-contraceptive benefits of contraceptive pills?
- reduced dysfunctional uterine bleeding and dysmenorrhea
- Menstrual regularity and inc. Hgb.
- combo pills raise SHBG, decrease androgens –> less hirsutism/acne
- combo pills used “off-label” to treat polycystic ovary syndrome
What are the available forms of spermicides?
- Nonoxynol-9 - most common, it’s a surfactant that comes in creams, foams, gels, suppositories, sponges; effective 1hr; must contact cervix
- Copper - available as IUD
Emergency contraception
- Progestins (levonorgestrel): 2 doses, 12hr apart within 72hr of IC (“morning-after pill”)
- Cu IUD inserted within 5d of IC
Antiprogestins or Contragestation drugs - MOA, names
- blocks binding of progesterone to its receptor
- Mifepristone or Onapristone (purer antagonist)
- Mifepristone approved for the termination of pregnancy (49 days or less into pregnancy)
Therapeutic use of androgens
- development/maintenance of male sex characteristics in androgen-deficient men
- endometriosis, PMS
- anabolic agents (athletes)
- maintain muscle mass in elderly men
Therapeutic use of AR antagonists and names
- Cyproterone acetate: used in treatment of acne, baldness, hirsutism, virilizing syndrome, inhibits libido in sex deviant males
- Flutamide, bicalutamide, nicalutamide: used in treatment of prostate cancer
- Spironolactone: treats 1˚ or 2˚ hyperaldosteronism, or as anti-HTN; treat hirsutism in women
5alpha-Reductase Inhibitor - there’s 1, name and MOA, uses
Finasteride: treats BPH, male pattern baldness; DON’T let near pregnant women, it can absorb through skin and cause birth defects in male fetus; men shouldn’t donate blood when taking
