Uterus Relaxants

Question 1

Write briefly on Oxytocics/ Uterine stimulants

Answer 1

• Oxytocin: Acts via GPCRs to increase intracellular Ca²⁺ and endometrial PG synthesis.
• Prostaglandins (PGE2, PGF2α): Initiate labor, sensitize uterus to oxytocin.
• Methylergometrine: Acts on 5HT2 and α-receptors causing sustained uterine contraction.
  Used for induction of labor, augmentation, and PPH control.

Question 2

Tocolytic agents/ Uterine Relaxants

Answer 2

• CCBs (Nifedipine): ↓ Ca²⁺ influx → uterine relaxation.
• MgSO₄: CNS depressant, smooth muscle relaxation.
• β2 agonists (Ritodrine, Salbutamol): Increase cAMP → relax uterus.
  Used to prevent preterm labor and threatened abortion.

Question 3

Indications of Prostaglandins in obstetric practice

Answer 3

• Cervical priming (PGE2 gel).
• Labor induction and augmentation.
• PPH control (Misoprostol, Carboprost).
• MTP (Misoprostol after Mifepristone or Methotrexate).

Question 4

Induction of labor with drugs

Answer 4

• Oxytocin: DOC, slow IV infusion.
• Prostaglandins: Dinoprostone gel (cervical ripening), Misoprostol (induction).
• Ensure proper presentation, fetal lung maturity, and cervical readiness.

Question 5

Drugs used for MTP (Medical Termination of Pregnancy)

Answer 5

• First trimester: Mifepristone 200mg oral + Misoprostol 400µg oral/sublingual.
• Second trimester: Misoprostol 800µg vaginal after Methotrexate 25–50mg oral.

Question 6

Compare Oxytocin and Prostaglandins

Answer 6

• Both stimulate uterine contractions.
• Oxytocin: Short acting, titratable, IV only, acts on fundus and body.
• PGs: Longer duration, cervix softening, vaginal/oral routes.
• PGs useful in preinduction priming, oxytocin for augmentation.

Question 7

Induction of labor at term

Answer 7

DOC: Oxytocin
Dose: 10 mU/min IV, increase to 2-4 U (5 IU in 500 ml D5/glucose).
Route: IV infusion.

Question 8

Therapeutic abortion

Answer 8

DOC: Mifepristone 200 mg orally, then Misoprostol 400 µg oral/sublingual after 36–48h.

Question 9

Treatment of PPH

Answer 9

DOC: Oxytocin 10U IM/IV.
Alternatives: Misoprostol 600-800 µg PR, Carboprost 0.25 mg IM, Methylergometrine 0.2–0.3 mg IM.

Question 10

MTP in 1st or 2nd trimester

Answer 10

• 1st trimester: Mifepristone + Misoprostol.
• 2nd trimester: Methotrexate 25–50 mg + Misoprostol 800 µg vaginally.

Question 11

Prevention of premature labor

Answer 11

DOC: Nifedipine 20 mg oral (repeat every 30 min until contractions stop).
Alternate: Ritodrine 50 µg/min IV.
Others: MgSO₄ IV drip.