OB-GYN

Question 1

• Methotrexate*
• Used for?*

Answer 1

Medications used for pregnancy termination

Ectopic pregnancy

Folic acid antagonist (inhibits dihydrofolate reductase)

Preferentially destroys proliferating fetal cells

Question 2

Mifepristone

Used for?

Answer 2

Medications used for pregnancy termination

Abortion

• Partial progesterone agonist (acts as progesterone antagonist during pregnancy)*
• Promotes placental separation & uterine contractions*

Question 3

Misoprostol

used for?

Answer 3

Abortion

Prostaglandin E1 agonist

Stimulates uterine contractions

Question 4

Mifepristone is a ___ ____ that binds progesterone receptors with greater affinity than the natural hormone.

__ ___ blockade results in apoptosis and necrosis of the uterine decidua and prevents further development of a first trimester pregnancy.

Answer 4

• progesterone antagonist*
• Progesterone receptor*

Question 5

When ____ is used with mifepristone, pregnancy termination success rate is increased.

_____, a prostaglandin E1 analog, causes ____ softening and ___ ___ leading to expulsion of the pregnancy.

Answer 5

When misoprostol is used with mifepristone, pregnancy termination success rate is increased.

Misoprostol, a prostaglandin E1 analog, causes cervical softening and uterine contractions leading to expulsion of the pregnancy.

Question 6

_____ (calcium channel blocker) and _____ (cyclooxygenase inhibitor) are tocolytic drugs used to stop preterm labor.

The decreased intracellular ___ from ____ blocks myosin kinase phosphorylation, which in turn leads to myometrial relaxation.

_____ stops prostaglandin synthesis, which decreases uterine contractility.

Answer 6

Nifedipine (calcium channel blocker) and indomethacin (cyclooxygenase inhibitor) are tocolytic drugs used to stop preterm labor.

The decreased intracellular calcium from nifedipine blocks myosin kinase phosphorylation, which in turn leads to myometrial relaxation.

Indomethacin stops prostaglandin synthesis, which decreases uterine contractility.

Question 7

Folic acid antagonists (eg, methotrexate) inhibit trophoblast division, therefore decreasing trophoblast survival, hindering implantation, and encouraging expulsion. Methotrexate is used for the treatment of ectopic pregnancy and for termination of intrauterine pregnancy in conjunction with misoprostol when mifepristone is not available.

Answer 7

Folic acid antagonists (eg, methotrexate) inhibit trophoblast division, therefore decreasing trophoblast survival, hindering implantation, and encouraging expulsion. Methotrexate is used for the treatment of ectopic pregnancy and for termination of intrauterine pregnancy in conjunction with misoprostol when mifepristone is not available.

Question 8

Oxytocin is a peptide hormone released by the posterior pituitary that stimulates uterine contractions. Myometrial oxytocin receptor concentration increases at term; therefore, oxytocin has limited effects on the uterus in early gestation and does not cause pregnancy termination.

Answer 8

Oxytocin is a peptide hormone released by the posterior pituitary that stimulates uterine contractions. Myometrial oxytocin receptor concentration increases at term; therefore, oxytocin has limited effects on the uterus in early gestation and does not cause pregnancy termination.

Question 9

Tamoxifen is a selective estrogen receptor modulator and is used primarily to treat estrogen receptor-positive breast cancer by selective blockade of estrogen-positive cancer cells. Conversely, in the uterus, tamoxifen stimulates endometrial estrogen receptors and can cause endometrial hyperplasia and endometrial adenocarcinoma.

Answer 9

Tamoxifen is a selective estrogen receptor modulator and is used primarily to treat estrogen receptor-positive breast cancer by selective blockade of estrogen-positive cancer cells. Conversely, in the uterus, tamoxifen stimulates endometrial estrogen receptors and can cause endometrial hyperplasia and endometrial adenocarcinoma.

Question 10

Progesterone is necessary for implantation and maintenance of pregnancy. Mifepristone is a progesterone antagonist that is used with misoprostol (a prostaglandin-E1 agonist) to terminate a first-trimester pregnancy.

Answer 10

Progesterone is necessary for implantation and maintenance of pregnancy. Mifepristone is a progesterone antagonist that is used with misoprostol (a prostaglandin-E1 agonist) to terminate a first-trimester pregnancy.