Contraceptives

Question 1

What are the 2 MOA of oral contraceptives

Answer 1

1. Preventing ovulation by suppressing LH/FSH relase from stable estrogen levels
2. Impairing implantation by maintaining elevated progesterone levels

Question 2

What are the estrogens uses for oral contraceptives?

Answer 2

• Ethinyl Estradiol
• Mestranol

Question 3

What are the progestins uses for oral contraceptives

Answer 3

• Norethindrone - highest androgenic activity
• Norgestrel
• Levonorgestrel
• Desogestrel
• Norgestimate
• Drospirenone - antiandrogenic

Question 4

Progestin Injection MOA, AE

Answer 4

• Depo-Provera - contains depot medroxyprogesterone acetate (DMPA)

MOA: prevents ovulation through negative feedback

AE: signficant loss of bone mineral density

Question 5

What are the emergency postcoital contraceptives

Answer 5

• Plan B and Next Choice
• Plan B One-Step
• Ella (Ulipristel acetate which is a Selective Progesterone Receptor Modulator) SPRM
• Norgestrel/Levonorgestrel Oral contraceptives high dose
• Copper IUD within 5 days

Question 6

What drugs can by used for Cervical Ripening and labor induction?

Answer 6

Cervical Ripening

• Dinoprostone - synthetic preparation of PGE2
• Misoprostol - PGE1 analog

Labor Induction (if not accomplished by cervical ripening)

• Oxytocin

Question 7

Oxytoxin MOA, AE

Answer 7

MOA: Gq > phospholipase C > release calcium from SR and acitvation of calcium channels > activation of MLCK > myometrial contraction; also increased prostaglandin synthesis

AE: high concentrartion can activate vasopressin receptors causing excessive fluid retention

Question 8

What is uses for management of Postpartum Hemorrhage?

Answer 8

• Oxytocin - first line
• Ergot Alkaloids
  
  • Methylergonovine (partial agonist alpha-adrenergic receptors and some serotonin receptors)
• Prostaglandins
  
  • ​Carboprost Tromethamine (PGF2alpha)
  • Misoprostol (PGE1)

Question 9

What are the most common tocolytics?

Answer 9

• Magnesium Sulfate - uncouples excitation-contration in myometrial cells by inhibition of cellular action potentials
• Indomethacin - NSAID to prevent prostaglandins can cause premature closure of ductus arteriosus so no recommended after 32 wks
• Nifedipine - CCB in myometrial cells inhibiting contractility

Question 10

What are the abortifacients and when are they used?

Answer 10

• Mifepristone (antiprogestin) - less than 8wks
• Misoprostol (prostaglandin analog) - less than 8wks
• Methotrexate (folic acid antagonist) - more than 8wks