Prostaglandins and Oxytocics 05/10/21

Question 1

What are Oxytocics?

Answer 1

A group of drugs that cause contractions of the uterine muscles

Question 2

What are the three groups of oxytocics called?

Answer 2

• Prostaglandins
• Oxytocin
• ergot derivatives (ergometrine)

Question 3

How do prostaglandins usually effect labour naturally?

Answer 3

-Due to decreasing progestogens and increasing oestrogen’s, it gradually increases the sensitivity of the uterus to prostaglandins and oxytocin. Stimulates the production of oxytocin receptors and sensitivity to oxytocin increase. Prostaglandins cause cervical ripening and dilatation causing uterine contractions also.

Question 4

What groups of oxytocics are used for induction and augmentation of labour?

Answer 4

-Oxytocin and Prostaglandins

Question 5

What groups of drugs are used for prevention of PPH?

Answer 5

-Oxytocin, ergometrine and syntometrine

Question 6

What groups of drugs are used for PPH management?

Answer 6

-Oxytocin, ergometrine, syntometrine and prostaglandins.

Question 7

When does the production of prostaglandin increase and reach a maximum?

Answer 7

At the time of placental separation.

Question 8

How to prostaglandins ripen the cervix?

Answer 8

PGE2 increases the production of enzymes that breakdown and loosen cervcal collagen.

Question 9

What are the two types of synthetic prostaglandins?

Answer 9

• Dinoprostone (prostin for IOL)

- Carboprost (management of PPH for last resort of if woman is hypertensive.)

Question 10

How is dinoprostone administered?

Answer 10

-Intravaginally, high in the posterior fornix using pessaries gel or tablets. If using tablets or gel, followed by second dose after 6 hours. If pessary, one dose over 24 hours.

Question 11

What are the side effects of prostaglandins?

Answer 11

-May cause genital oedema. Risk of hyper stimulation and uterine rupture. Can cause nausea and vomiting and abdominal pain.

Question 12

What are the contraindications for prostaglandins?

Answer 12

• Grand multiparas
• Previous Csection
• Placenta praaevia
• Uterine surgery

Question 13

How is carboprost administered?

Answer 13

-IM injection for PPH. Can cause chills, headache, diarrhoea.

Question 14

Where is oxytocin made and stored naturally?

Answer 14

Synthesised in the hypothalamus and transported and stored in the posterior pituitary.

Question 15

Mechanism of oxytocin?

Answer 15

• Stretching of the cervix of the uterus
• Activation of stretch receptors within layers of the uterus
• Signal sent to the hypothalamus and oxytocin secreted from the pituitary gland in pulses
• Oxytocin binds to receptors on smooth muscle cells located in the myometrium
• Overall effect is the increased intracellular calcium levels
• Increases uterine contractions

Question 16

Does oxytocin suppress normal physiological uterine contractions?

Answer 16

No. Endogenous release is NOT suppressed by exogenous administration.

Question 17

How long does It take for syntocinon (oxytocin) to act IM?

Answer 17

Within 3-7 minutes lasting 30-60 minutes.

Question 18

How long does it take for oxytocin to work IV?

Answer 18

Acts within 1-4 minutes. Stabilises contractions within 15-60 minutes and metabolised in the liver, spleen ovaries and placenta.

Question 19

What is carbetocin and what is it used for?

Answer 19

Synthetic form of oxytocin. Used for prevention of uterine atony after section. Given as slow IV injection as soon as possible. Increases rate and force of spontaneous contractions and firm contraction within 2 minutes.

Question 20

What is syntometrine?

Answer 20

Combination of oxytocin and ergometrine. Immediate effect of oxytocin and slight delayed effects of ergometrine.