Pharmacology

Question 1

What are the tocolytic drugs?

Answer 1

Beta 2-agonists (e.g. terbutaline), calcium channel blockers (e.g. nifedipine), oxytocin receptor antagonists (e.g. atosiban), NSAIDs (e.g. indomethacin),

Question 2

What are common drugs used to treat HTN in pregnancy?

Answer 2

Methyldopa, labetalol, and nifedipine. Hydralazine is sometimes used for severe HTN seen in preeclampsia.

Question 3

What medication is often used in pregnancy to treat migraine headaches?

Answer 3

Amitriptyline

Question 4

What treatment should be provided to a woman who tests positive for syphilis with a penicillin allergy?

Answer 4

Desensitization and administer penicillin G

Question 5

What medication is given to pregnant women with symptomatic mitral valve prolapse?

Answer 5

A beta-blocker

Question 6

How is pruritus gravidarum (a mild variant of intrahepatic cholestasis of pregnancy) treated?

Answer 6

Antihistamines and topical emollients may provide some relief and should be used initially. Ursodeoxycholic acid is the most effective agent for relieving pruritus and lowering serum enzyme levels. Naltrexone has also been shown to provide relief.

Question 7

What are signs of magnesium toxicity?

Answer 7

Muscle weakness, drowsiness, loss of deep tendon reflexes, nausea, decreased urine output, and respiratory depression

Question 8

How is respiratory depression secondary to magnesium toxicity treated?

Answer 8

Stop the magnesium and give calcium gluconate

Question 9

What is the therapeutic range for magnesium?

Answer 9

4-7 mEq/L

Question 10

At how many weeks gestation should indomethacin not be used as a tocolytic?

Answer 10

32 wks - risk for ductus closure

Question 11

What medications are preferred as tocolytics?

Answer 11

Indomethacin (before 32 wks) and nifedipine. Note that beta-agonists (e.g. terbutaline) should not be used to stop preterm labor because use of longer than 48-72 hrs is associated with adverse outcomes. Terbutaline may be useful for slowing tachysystole. Oxytocin receptor antagonists (e.g. atosiban) and magnesium sulfate are less effective.

Question 12

What is magnesium sulfate’s mechanism of action as a tocolytic?

Answer 12

Competes with calcium for entry into cells

Question 13

What are side effects of terbutaline?

Answer 13

Tachycardia, hypotension, anxiety, and chest tightening

Question 14

What medications should be given to women with PPROM?

Answer 14

Ampicillin and erythromycin - these medications have been found to prolong the latency period by 5-7 days, as well as reduce the incidence of maternal amnionitis and neonatal sepsis.

Question 15

What is 17 alpha-hydroxyprogesterone useful for during pregnancy?

Answer 15

Prevention of premature labor - administered weekly starting between 16-20 wks to 36 wks gestation if there is a concern.

Question 16

What should be considered about using prostaglandins for cervical ripening in a woman with a prior C-section?

Answer 16

Prostaglandins are contraindicated as they increase the risk for uterine rupture.

Question 17

What are the urotonic agents?

Answer 17

Methylergonovine, prostaglandins, misoprostol and oxytocin - used to increase uterine contractions and decrease uterine bleeding

Question 18

What urotonic is contraindicated in the setting of preeclampsia?

Answer 18

Methylergonovine - it is an ergot alkaloid which can cause vasoconstriction in addition to uterine contraction

Question 19

What urotonic should not be used in the setting of steroid-dependent asthma?

Answer 19

Prostaglandin F2-alpha - acts as a potent smooth muscle constrictor along with a bronchio-constrictive effect

Question 20

What antibiotic is recommended for management of suspected endometritis during labor (sx of fundal tenderness in setting of prolonged rupture of membranes and multiple vaginal examinations)?

Answer 20

Gentamicin - usually polymicrobial with mostly anaerobic organisms so requires a broad-spectrum agent

Question 21

What antibiotics are indicated for endometritis following a C-section?

Answer 21

Gentamicin plus clindamycin is the gold standard regimen

Question 22

How is antiphospholipid antibody syndrome treated during pregnancy?

Answer 22

Aspirin and heparin - to prevent pregnancy loss

Question 23

What are absolute contraindications to methotrexate use in the setting of ectopic pregnancy?

Answer 23

Breastfeeding, liver dysfunction, renal dysfunction, dyscrasias, ruptured ectopic

Question 24

What is the recommended calcium dosage for postmenopausal women?

Answer 24

1200 mg

Question 25

What OTC supplement is helpful for treating bot the physical and emotional symptoms of PMS?

Answer 25

At least 1,200 mg daily of calcium.

Pyridoxine (B6) and vitamin E may also be of benefit. There is less convincing evidence for magnesium.

Question 26

What are the criteria for methotrexate usage in ectopic pregnancy?

Answer 26

• Tubal mass < 4 cm
• No embryonic heartbeat (with some exceptions)
• No intra-abdominal hemorrhage seen
• No contraindications to methotrexate therapy (e.g. immunocompromised, active pulmonary disease, etc)
• Patient will be available for long-term follow-up
• Pain is not severe

Question 27

Is a prior ectopic pregnancy a contraindication for methotrexate therapy in a current ectopic pregnancy?

Answer 27

No

Question 28

What tocolytics are contraindicated in diabetes?

Answer 28

Terbutaline and ritodrine (no longer on the U.S. market)

Question 29

What is the physiology behind hypotension after epidural placement?

Answer 29

Occurs in about 10% of women - happens when the sympathetic nerve fibers responsible for vascular tone are blocked, resulting in vasodilation (venous pooling), decreased venous return to the right side of the heart, and decreased cardiac output. It can be prevented by aggressive IV fluid volume expansion prior to epidural placement. Treatment includes positioning the patient on the left side, an IV fluid bolus, and/or vasopressors

Question 30

What medications should be administered to a woman who goes into preterm labor at <32 weeks gestation?

Answer 30

Betamethasone, tocolytic (e.g. indomethacin, nifedipine), magnesium sulfate (neuroprotection for baby), penicillin if GBS positive or unknown. Note that it is the same for preterm labor at 32-33 6/7 minus the magnesium sulfate. At 34 weeks, a tocolytic is not needed and clinical judgement can be used regarding betamethasone.

Question 31

What medication is often given to treat intrahepatic cholestasis of pregnancy?

Answer 31

Ursodeoxycholic acid (however, naltrexone may also be used to relieve itching).

Question 32

What are signs of oxytocin toxicity?

Answer 32

Hyponatremia (due to water intoxication - similar in structure to ADH), hypotension, and tachysystole. Hyponatremia may lead to headaches, abdominal pain, nausea, vomiting, lethargy, and tonic-clonic seizures

Question 33

What is the most common side effect of long-term heparin use in pregnancy?

Answer 33

Osteoporosis

Question 34

What are the absolute contraindications for hormone replacement therapy?

Answer 34

The presence of estrogen-dependent tumors (breast or uterus), active thromboembolic disease, undiagnosed genital tract bleeding, active severe liver disease or malignant melanoma

Question 35

What are the adverse affects of oxytocin?

Answer 35

Hyponatremia, tachysystole, and hypotension