Oral Contraceptives

Question 1

What are Oral Contraceptives?

Answer 1

● Usually contain a mixture of estrogen & progestin which act by inhibiting ovulation
● Relatively high level of estrogen and progestins inhibits release of GnRH, FSH / LH from pituitary so that the follicle does not develop (ovulation does not occur)
● C-19s produce thick, hostile environment for sperm migration (major MOA)

Question 2

Which are the different types of oral contraceptives?

Answer 2

● Combined
● Sequential
● Continuous low dose progestin (“minipill”)
● Phasic
● Depot Therapy
● Patch
● Subdermal Implants
● Post-coital Contraceptives
● Mifepristone (RU486)

Question 3

What are the main characteristics of Combined therapy?

Answer 3

● Estrogen & progestin on days 5-25 (followed by placebo pills)
● Theoretical effectiveness = 99.9%

Question 4

What are the main characteristics of Sequential therapy?

Answer 4

● Estrogen alone for 15 days, then estrogen and progesterone for 5 days
● Discontinued – risk of endometrial cancer (due to unopposed estrogen)

Question 5

What are the main characteristics of Continuous low dose progestin (“minipill”) therapy?

Answer 5

● Progestin only
● Not reliable as an inhibitor of ovulation (block in only 75-80% of cycles)
● Increased incidence of unpredictable spotting and breakthrough bleeding
● Advantage = serious side effects of combo therapy (ex: clotting,
thrombosis) are due to estrogen component and are hence eliminated

Question 6

What are the main characteristics of Phasic therapy?

Answer 6

● Varying doses of estrogen and progestin components during the month to more closely approximate a normal menstrual cycle

Question 7

What are the main characteristics of Depot therapy?

Answer 7

● Injections of long-lasting estrogens and/or progestins

● Medroxyprogesteron acetate (Depo-Provera®) – give IM 1x / 3 months

Question 8

What are the main characteristics of Patch therapy?

Answer 8

● Ortho-Evra – apply patch once a week

Question 9

What are the main characteristics of Subdermal Implant therapy?

Answer 9

● Capsules of etonorgestrel under skin for slow release (work up to 3 years)

Question 10

What are the main characteristics of Post-Coital therapy?

Answer 10

● MOA: prevent implantation of the fertilized ovum and/or alter motility of the fertilized ovum through Fallopian tube
● Severe nausea / vomiting = side effect of high estrogen content pills
● Plan B

Question 11

What are the main characteristics of Mifepristone (RU486) therapy?

Answer 11

● Progesterone antagonist that inhibits the actions of progesterone on the uterus during luteal phase; can detach embryo from uterine wall leading to abortion → administered with misoprostol (a prostaglandin) to expel embryo