Week 4: Reproductive Pharmacology: Drugs to prevent or postpone pre-term labor

Question 1

Progesterone MOA

Answer 1

• Progesterone receptor agonist

Question 2

Progesterone clinical uses

Answer 2

• off-label use for prevention of spontaneous preterm delivery (singleton pregnancy and prior preterm birth or short cervix

Question 3

Progesterone side effects

Answer 3

• Minor side effects are related to the route of administration and include
  
  • injection site reactions
  • vaginal irriation or discharge

Question 4

Progesterone notes

Answer 4

Randomized trials have provided convincing evidence that progesterone supplementation reduces the rate of spontaneous singleton preterm birth in women who have had a previous spontaneous preterm singleton birth with a short cervix on ultrasound examination in current pregnancy

Question 5

Magnesium sulfate MOA

Answer 5

Reduces Ca²⁺ influx

Question 6

Magnesium Sulfate clinical uses

Answer 6

Tocolytic agents that postpone preterm labor by reducing uterine muscle contraction

Question 7

Magnesium Sulfate side effects

Answer 7

maternal toxicities include

• maternal toxicity flushing
• muscle weakness
• headache
• somnolence
• double vision
• dry mouth
• slurred speech

fetal and neonatal effects include

• lethargy
• hypotonia
• respiratory depression

Question 8

Magnesium Sulfate contraindications

Answer 8

N/A

Question 9

Magnesium Sulfate notes

Answer 9

Less effective than Nifedipine in delaying delivery

Question 10

Nifedipine MOA

Answer 10

Ca²⁺ channel blocker (reduces uterine muscle contraction)

Question 11

Nifedipine clinical uses

Answer 11

Tocolytic agents that postpone preterm labor by reducing uterine muscle contraction

Question 12

Nifedipine side effects

Answer 12

Nifedipine is a peripheral dilator thus it may cause symptoms such as

• nausea
• flushing
• headache
• dizziness
• palpitations

Question 13

Nifedipine contraindications

Answer 13

Ca²⁺ channel blockers are contraindicated in women with

• hypotension or pre-load dependent cardiac lesions
• use with caution in women with left ventriicular dysfunction or congestive heart failure

The concomitant use of a Ca²⁺ channel blocker and magnesium sulfate could act synergistically to suppress muscular contractility which culd result in respiratory depression

Question 14

Terbutaline MOA

Answer 14

β2 adrenergic receptor agonist

Question 15

Terbutaline clinical uses

Answer 15

Tocolytic agents that postpone preterm labor by reducing uterine muscle contraction

Question 16

Terbutaline Side effects

Answer 16

• Dizziness
• Drowsiness
• Difficulty breathing
• Irregular heartbeat
• Maternal hyperglycemia
• cardiac arrhythmias
• myocardial ischemia
• pulmonary edema
• hypotension
• tachycardia
• The infrequent and fetal tachycardia, hyperinsulinemia, hyper glycermia, myocardial and septal hypertrophy and myocardial ischemia

Question 17

Terbutaline contraindications

Answer 17

2011 FDA warning:

• Injectable terbutaline should not be used to treat preterm labor for more than 48-72 hours

Contraindicated if the mother has cardiac arrhythmia