CH 65 Birth Control Flashcards
Drug: Ethinyl estradiol + progestin (Yaz, Ortho Tri-Cyclen)
Class: Combined oral contraceptive (COC)
MOA: Suppresses ovulation via negative feedback on GnRH, FSH, and LH; also thickens cervical mucus and thins the endometrium.
Note: May reduce acne, ovarian cysts, and cancer risk; contraindicated in smokers over 35 due to thrombotic risk.
Drug: Norethindrone (Camila, Errin, others)
Class: Progestin-only oral contraceptive (“mini pill”)
MOA: Thickens cervical mucus and thins the endometrium; may inhibit ovulation in some users.
Note: Must be taken at the same time every day; backup contraception needed if more than 3 hours late.
Drug: Etonogestrel implant (Nexplanon)
Class: Long-acting reversible contraceptive (LARC), progestin-only
MOA: Inhibits ovulation and thickens cervical mucus.
Note: Effective for up to 3 years; among the most effective contraceptive methods.
Drug: Depot medroxyprogesterone acetate (Depo-Provera)
Class: Injectable contraceptive (progestin)
MOA: Suppresses ovulation, thickens cervical mucus, and thins endometrial lining.
Note: Administered every 3 months; may cause delayed return to fertility and bone loss with long-term use.
Drug: Levonorgestrel IUD (Mirena, Skyla, Liletta, Kyleena)
Class: Intrauterine device (progestin)
MOA: Releases levonorgestrel locally to thicken cervical mucus and suppress endometrial growth.
Note: Long-acting (3–8 years depending on type); may reduce menstrual bleeding and cramping.
Drug: Copper IUD (Paragard)
Class: Intrauterine device (non-hormonal)
MOA: Copper ions induce an inflammatory response toxic to sperm and eggs, preventing fertilization.
Note: Effective for up to 10 years; can increase menstrual bleeding and cramps.
Drug: Contraceptive patch (Xulane, Twirla)
Class: Transdermal contraceptive (estrogen + progestin)
MOA: Inhibits ovulation and alters cervical mucus and endometrial lining.
Note: Changed weekly; may be less effective if body weight >198 lbs (Xulane) or BMI >30 (Twirla).
Drug: Vaginal ring (NuvaRing, Annovera)
Class: Vaginal contraceptive (estrogen + progestin)
MOA: Releases hormones locally to inhibit ovulation and alter cervical mucus.
Note: Inserted for 3 weeks, removed for 1 week; Annovera is reusable for 1 year.
Drug: Levonorgestrel emergency contraception (Plan B One-Step)
Class: Emergency contraceptive (progestin-only)
MOA: Inhibits or delays ovulation; may alter tubal transport of sperm/egg.
Note: Most effective within 72 hours of unprotected sex; does not terminate an existing pregnancy.
Drug: Ulipristal acetate (Ella)
Class: Emergency contraceptive (selective progesterone receptor modulator)
MOA: Delays ovulation even when LH surge has begun.
Note: Prescription-only; effective up to 5 days after unprotected intercourse.
Drug: Spermicides (Nonoxynol-9)
Class: Chemical contraceptive
MOA: Disrupts sperm cell membranes, immobilizing and killing sperm.
Note:
* Available OTC
* low effectiveness when used alone
* increased effectiveness when used w/ diaphragm or condom (or both)
Drug: Mifepristone (Mifeprex, Korlym)
Class: Progesterone receptor antagonist
MOA: Blocks progesterone receptors in the uterus, leading to endometrial breakdown and detachment of pregnancy.
Note: Used with misoprostol for medical abortion; also used for Cushing’s syndrome at lower doses.
What are the main types of birth control and their contraception rates?
- barrier methods (e.g., condoms, ~85% effective)
- hormonal methods (e.g., OCs, implants, ~91–99%)
- IUDs (~99%) NOT appropriate for those at risk for STDs
- sterilization (~99%)
What are common benefits of hormonal birth control?
- Regulates periods
- reduces acne
- lowers risk of ovarian and endometrial cancers
- decreases menstrual cramps
What are common adverse effects of hormonal contraceptives?
- Nausea
- breast tenderness
- mood changes
- increased blood clot risk, especially in smokers >35 years
What is the ‘mini pill’?
A progestin-only oral contraceptive (no estrogen).
- Must be used CONTINUOUSLY
- Missing dose by 3 hours = missed dose
What is a main advantage of the mini pill compared to combination OCs?
- Lower clotting risk
- safer for breastfeeding and for women who can’t take estrogen.
What is a monophasic oral contraceptive?
Each active pill contains the same amount of estrogen and progestin.
What is a biphasic oral contraceptive?
Has two different hormone combinations in the active pills to better mimic the menstrual cycle.
* 1st half: higher estrogen
* 2nd half: increase in progestin
What is a triphasic oral contraceptive?
Has three varying hormone doses throughout the cycle to more closely mimic natural hormone fluctuations.
How do oral contraceptives interact with warfarin?
OCs may reduce warfarin effectiveness by increasing clotting factor synthesis (estrogen effect).
How do OCs interact with anticonvulsants like phenytoin?
Anticonvulsants induce liver enzymes, reducing OC effectiveness by increasing estrogen metabolism.
Do tetracyclines and ampicillin reduce OC effectiveness?
Evidence is inconclusive, but backup contraception is often recommended during use.
How do OCs affect theophylline levels?
OCs may increase theophylline levels by inhibiting its metabolism, increasing toxicity risk.
