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
What does ACOG recommend for contraceptives for adolescents and young adults that are/may become sexually active?
IUDs and implants
Describe the failure rate in the first year of use for:
Condoms
Depo provera shot
Condoms: 20%
DP shot: 6%
all mostly due to user failure
Why are pts on COC at reduced risk of pelvic inflammatory disease?
Thickened cervical mucus (blocks entry), reversed peristalsis (blocks tubal advance), and thinned, less welcoming endometrial lining all oppose bacterial seeding in upper genital tract.
Describe the black box warming for depo provera (DP).
Do physicians actually heed this warning?
Bone loss. If you have been on DP for 3 yrs, you should come off to prevent bone loss. Bone loss due to decreased estrogen levels.
Docs don’t actually pull pts off DP because they can just supplement Ca2+. No pathologic fxs have been linked to DP, ever.
Describe the differences in Mirena, Skyla, and the copper IUD.
Mirena: lasts 5 yrs
non-contrac. benefits: amenorrhea
Skyla: lasts 3 yrs
For nulliparous, younger women
Copper IUD: lasts 10 yrs
Non-hormonal, women have regular periods. Does not effect ovulation.
SFX: dysmenorrhea, heavy periods
Contraindications: Cu allergy, Wilson’s disease (accumulate Cu)
Which method of non-oral contraception eliminates periods all together?
Depo Provera shot
What is the most effective emergency contraceptive method?
Cu IUD. Must be in place within 72 hrs of conception. Prevents implantation.
