Uterotonics & Tocolytics

Question 1

Muscle Contraction

Answer 1

Myosin Light Chain Kinase

Calcium ios

Question 2

Muscle Relaxation

Answer 2

Protein Kinase A (PKA)

Question 3

Uterotonics Medications?

Answer 3

Oxytocin
Ergonovine
Prostaglandin ( Misoprostol & Dinoprostone)

Question 4

OXYTOCIN

Answer 4

MOA: Activates GQ
Activates PHOSPHOLIPASE C
Opens CALCIUM IONS
CALCIUM bind to CALMODULIN
Activate MYOSIN LIGHT CHAIN KINASE
MUSCLE CONTRACTION

Question 5

Oxytocin

Answer 5

DOC for LABOR INDUCTION
IV/IM
Other use: prevent post partum hemorrhage

Question 6

Oxytocin Side effects?

Answer 6

♡Vasodilation–hypotension & reflex tachycardia
♡Activate ADH receptor in collecting duct – water retention
♡Uterine hyperstimulation–uterine rupture

Question 7

Ergonovine

Answer 7

•Use: PPH
•Causes prolonged uterine tetany--NOT USED TO INDUCE LABOR
•IV/IM
•SE: Vasoconstriction-- inc BP
Vasospasm-- may trigger angina
N/v, blurred vision, headache

☆ AVOIDED IN HYPERTENSIVES ☆

Question 8

Prostaglandins
□DINOPROSTONE– C/I ASTHMATICS☆
□MISOPROSTOL

Answer 8

■MOA: Activate GQ
■USE: Faciitate labor, PPT, ABORTION☆
■Oral, vaginal,intracervical

Question 9

Uterine Relaxants

Answer 9

▪︎Selective B2 Agonist (TERBUTALINE)
▪︎CCB (NIFEDIPINE)
▪︎COXi (INDOMETHACIN)
▪︎Oxytocin Receptor antagonist (ATOSIBAN)

Question 10

B2 Agonist (TERBUTALINE)

Answer 10

■MOA: Gs stimulates Adenylyl cyclase (ac)
Ac takes ATP and removes 2 phosphates to become
cAMP– activate Protein Kinase A (PKA)– INHIBIT UTERINE CONTRACTION ☆
■ PO, SQ, IV

Question 11

CCB (NIFEDIPINE)

Answer 11

▪︎one of the DOC for preterm labor
▪︎PO or Parenteral
▪︎ SE: Vasodilation– flushing, dizziness

Question 12

COXi (INDOMETHACIN)

Answer 12

▪︎One of the DOC also for preterm labor
▪︎MOA: Inhibits Prostaglandin – inhibits contraction

♡ Prostaglandin:
▪︎Delays closure of Ductus arteriosus
▪︎Promote platelet aggregation
♡COXi– remove prostaglandin– premature closure of DA and bleeding