Contraceptives Flashcards
Contraceptives work by
- Supressing
- Ovulation
- Gametogenesis
- Interfering with gestation
Major classes of contraceptives
- Combined oral contraceptives
-
Progestin only
- less commonly used
- Transdermal patch
- Vaginal ring
- Dermal implants
- Intrauterine device
- Postcoital
Major Estrogen analogues
- Ethinyl estradiol
- Mestranol
- Pro-drug
- 50% metabolized into ethinyl estradiol
Progestins
- Medroxyprogesterone
- Northindrone
- Etonogestrel
- Levonogestrel
- Norelgestromin
- Norgestral
- Norgestimate
- the only one without ANDROGENIC activity
Combined oral contraceptive
Monobasic
Constant dose estrogen and progestin
- adminstered daily for 21 days strating from day 5 of cycle
- During the last 7 days, this drug is substituted for a placebo and the drug can be withdrawn
Combined oral contraceptives
Tribasic
-
Constant estrogen
- Ethinyl estradiol- 30µg
- Used to momic the menstrual cycle
-
Variable Progestins
-
Norgestrel
- 1-6 days (50µg)
- 7-11 days (75µg)
- 12-21 days (125µg)
-
Norgestrel
Progestin only pills
Composed of
Norethindrone or norgestrel
Progestin only pills
Effectiveness
Less than combied oral contraceptives
Progestin only pills
Associated with
- Iregular menstrual bleeding
- Limited patients acceptance
- anxiety of getting since its less effective
Progestin only pills
Preferential use
- Breast feeding
- Progestin does NOT prevent milk production
- Estrogen does
- Intolerable to estrogen
- Smokers with existing cardiovascular complications
Transdermal patch composed of
Ethinyl estradiol and Norelgestromin
Transdermal patch applied to
The abdomen for 3 weeks. Stop for a week (bleed) and then again
Transdermal patch
Total estrogen exposure
60%> than oral contraceptives (combined)
- Because there is no first pass metabolism
- Less effective in obese females because there is more fat
Vaginal rings are composed of
Ethinyl Estradiol and Etonogestrel
Vaginal rings application
Taken for 3 weeks. Stopped for a week
Vaginal rings
Cons
Slips
Progestin implants composed of
Etonogestrel
Progestin implants adminstered
- 4cm capsule
- Placed in the SubQ tissue of upper arm
- Releases progestin for 3 years
- If removed, effects are reversed within a month
Progestin itrauterine device composed off
Levonor gestrel-releasing intrauterine system
- maintains contraception for 5 years
Progesrtin intrauterine device contraindicated in
- Pelvic inflammatory disease
- Ectopic pregnancy
Levonor-gestrel (0.75mg)
- Post coital
- Adminstered 48-72 hours post coitus
- 2 doses 12 hours apart
Ethinyl estradiol (100ug) and 0.5mg L gestrel
- Combination
- 2 doses 12 hours apart
- within 48-72 hours
Mifepristone and Misoprostol
Mifepristone (RU 486)
- Progestin receptor blocker
- may induce abortion
48 hrs later…
Misoprostol
- prostaglandin receptor analogue
MOA
- Supress ovulation
- Estrogen inhibits LH,FSH therefore no LH surge
- Estrogen decreases pituitary response to GnRH
- Progestin analogue
- Increases thickness of cervical mucose
- Less permeable to sperm
- Endometrium less receptive to ovum
- Inhibits tubular peristalsis
- Increases thickness of cervical mucose
