Reproductive System

Question 1

Uworld: Pharmacology:
Describe the MOA of Letrozole:

Answer 1

Acts on the ovaries and peripheral adipose tissue to inhibit Aromatase. Therefore inhibiting the androgen-to-estrogen conversion. The decreased in estrogens (ovarian estradiol and adiposal estrone) increases the release of FSH and LH from the pituitary to stimulate ovulation.
Uses: PCOS or other causes of anovulation

Question 2

Uworld: Pharmacology:
Describe the MOA of Clomiphene:

Answer 2

Acts on estrogen receptors in the Hypothalamus and Pituitary. Binds for an extended period depleting its receptors to continue the release of FSH and LH despite high amounts of Estrogen. (eliminates the negative feedback).

Question 3

Bootcamp: Pharmacology
What is the difference between Mifepristone and Misoprostol in its effect to terminate a pregnancy?

Answer 3

Mifepristone is a progesterone receptor antagonist while Misoprostol is a PGE1 analog. Typically used in combination.