Breast Cancer and Uterine Drugs Flashcards
oxytocin (indication, mech, toxicity)
synthetic version of endogenous hormone.
Indication: labor induction, augmentation of dysfunctional labor, control post-partum hemorrhage.
Mech: binds to oxytocin receptor, alters transmembrane potential, increasing uterine (smooth muscle) contraction.
Note: uterus is more sensitive to oxytocin during gestation, and even more during labor.
Tox: Uterine tachysystole
oxytocin (indication, mech, toxicity)
synthetic version of endogenous hormone.
Indication: labor induction, augmentation of dysfunctional labor, control post-partum hemorrhage.
Mech: binds to oxytocin receptor, alters transmembrane potential, increasing uterine (smooth muscle) contraction.
Note: uterus is more sensitive to oxytocin during gestation, and even more during labor.
Tox: Uterine tachysystole
Misoprostol (indication, mech, tox)
prostaglandin used off-label to induce labor, prevent post-partum hemorrhage; induce contractions after missed or incomplete miscarriage in early pregnancy.
CI: prev C-section
Methylergometrine (indication, toxicity)
used to prevent post-partum hemorrhage after dilation and curettage. Vasoconstrictive- increases uterine motor activity and leads to sustained contraction at high doses.
Tox: Do not use if HTN.
Tocolytic agents: def, indication
Relaxes uterus. Used to delay preterm delivery for administration of corticosteroids for fetal lung development.
Tocolytic agents: examples
Mg Sulfate; Tertbutaline; Ca channel blockers, NSAIDs
Magnesium sulfate
Used to prevent seizures in preeclampsia. Neuroprotective for fetus. Mech is Ca-channel blockade.
Magnesium sulfate
Used to prevent seizures in preeclampsia. Neuroprotective for fetus. Mech is Ca-channel blockade.
Tamoxifen (indication, mech, tox)
for ER+ breast cancer in pre AND post menopausal women. Mechanism is blockade of alpha ER in breast (partial agonist in endometrium).
Tox: menopausal sx; vaginal discharge, cataracts, nausea. Black Box: Inc. risk of DVT, endometrial cancer
30-40% become resistant in 5 yrs (down regulation of ER-alpha)
Tamoxifen (indication, mech, tox)
for ER+ breast cancer in pre AND post menopausal women. Mechanism is blockade of alpha ER in breast (partial agonist in endometrium).
Tox: menopausal sx; vaginal discharge, cataracts, nausea. Black Box: Inc. risk of DVT, endometrial cancer
30-40% become resistant in 5 yrs (down regulation of ER-alpha)
Cyp2D6 and tamoxifen
Tamoxifen is activated and metabolized by Cyp2D6, for which there are many polymorphisms. Poor metabolizers had worse survival than other genotypes. FDA used to recommend screening, but no longer does.
Tamoxifen (indication, mech, tox)
for ER+ breast cancer in pre AND post menopausal women. Mechanism is blockade of alpha ER in breast (partial agonist in endometrium).
Tox: menopausal sx; vaginal discharge, cataracts, nausea. Black Box: Inc. risk of DVT, endometrial cancer
30-40% become resistant in 5 yrs (down regulation of ER-alpha)
CI if Hx of DVT, PE, pregnancy. do not combine w/ SSRIs (inhibit cyp2D6).
Cyp2D6 and tamoxifen
Tamoxifen is activated and metabolized by Cyp2D6, for which there are many polymorphisms. Poor metabolizers had worse survival than other genotypes. FDA used to recommend screening, but no longer does.
Raloxifene
SERM to treat breast cancer in POST menopausal women with ER+ cancer only. Less efficacious than tamoxifen, but not a pro-drug so does not require activation by CYP2D6.
**Lower risk of endometrial cancer
CI in DVT, pregnancy.
Anastrozole
Indicated for Tx of ER+ breast cancer in POST-menopausal women (only)
REVERSIBLE Aromatase inhibitor- reduces conversion of testosterone to estrogen.
Used as an adjuvant monotherapy for up to 5 years (after 5 years of Tx with a SERM).
Tox: Hot flashes, osteopenia, osteoporosis.
Won’t work on pre-menopausal women due to effect of functional ovaries.
