Page 700 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

656 SectioN iii RepRoductive ` REPRODUCTIVE—PHARmACOlOgy RepRoductive ` REPRODUCTIVE—PHARmACOlOgy

Goserelin, leuprolide
mECHANISm GnRH analogs. When used in pulsatile Leuprolide can be used in lieu of GnRH.
fashion act as GnRH agonists. When used
in continuous fashion first transiently act as
GnRH agonists (tumor flare), but subsequently
act as GnRH antagonists (downregulate
GnRH receptor in pituitary Ž  FSH and
 LH).
ClINICAl USE Uterine fibroids, endometriosis, precocious
puberty, prostate cancer, infertility.

ADVERSE EFFECTS Hypogonadism,  libido, erectile dysfunction,
nausea, vomiting.

Degarelix
mECHANISm GnRH antagonist. No start-up flare.
ClINICAl USE Prostate cancer.
ADVERSE EFFECTS Hot flashes, liver toxicity.

Estrogens Ethinyl estradiol, DES, mestranol.
mECHANISm Bind estrogen receptors.
ClINICAl USE Hypogonadism or ovarian failure, menstrual abnormalities (combined OCPs), hormone
replacement therapy in postmenopausal women.
ADVERSE EFFECTS  risk of endometrial cancer (when given without progesterone), bleeding in postmenopausal
women, clear cell adenocarcinoma of vagina in females exposed to DES in utero,  risk of
thrombi. Contraindications—ER ⊕ breast cancer, history of DVTs, tobacco use in women > 35
years old.

Selective estrogen receptor modulators

Clomiphene Antagonist at estrogen receptors in hypothalamus. Prevents normal feedback inhibition and
 release of LH and FSH from pituitary, which stimulates ovulation. Used to treat infertility due
to anovulation (eg, PCOS). May cause hot flashes, ovarian enlargement, multiple simultaneous
pregnancies, visual disturbances.
Tamoxifen Antagonist at breast; agonist at bone, uterus;  risk of thromboembolic events (especially with
smoking) and endometrial cancer. Used to treat and prevent recurrence of ER/PR ⊕ breast
cancer.
Raloxifene Antagonist at breast, uterus; agonist at bone;  risk of thromboembolic events (especially with
smoking) but no increased risk of endometrial cancer (vs tamoxifen); used primarily to treat
osteoporosis.

Aromatase inhibitors Anastrozole, letrozole, exemestane.
mECHANISm Inhibit peripheral conversion of androgens to estrogen.
ClINICAl USE ER ⊕ breast cancer in postmenopausal women.

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