GOSH drugs

Question 1

Why should methotrexate be stopped 3 months prior to conception/pregnancy in both the woman and man trying to conceive?

Answer 1

Methotrexate is teratogenic and can also cause abortions. Embryopathy includes craniofacial defects, spine and rib defects and defects of the digits. It is advised that both women and men should be off methotrexate for 3 months before attempting to conceive to avoid these problems.

Question 2

What is mifepristone?

Answer 2

Mifepristone, an antiprogestogenic steroid, sensitises the myometrium to prostaglandin-induced contractions and ripens the cervix

Question 3

What is the mechanism of action of mifepristone?

Answer 3

Mifepristone is a progesterone hormone antagonist, it inhibits progesterone, causing bleeding by releasing endogenous prostaglandins. It also sensitises the myometrium to the contraction-inducing effect of the prostaglandins, and it ripens the cervix.

Question 4

What are the indications for use mifepristone? (4)

Answer 4

1. Medical termination of intrauterine pregnancy (up to 49 weeks generally)
2. Cervical ripening before mechanical cervical dilatation for termination of pregnancy up to 84 days gestation
3. Labour induction in fetal death (where prostaglandin/oxytocin are inappropriate)
4. Termination of pregnancy of 13–24 weeks gestation (in combination with a prostaglandin)

Question 5

What are the contraindications for use of mifepristone? (3)

Answer 5

1. Acute porphyrias
2. Suspected ectopic pregnancy
3. Chronic adrenal failure

Question 6

What are the side effects of mifepristone? (6)

Answer 6

1. Abdominal cramps
2. Diarrhoea
3. Infection / PID
4. Nausea
5. Vaginal haemorrhage
6. Vomiting

Question 7

What is misoprostol?

Answer 7

Misoprostol is a synthetic prostaglandin analogue that has antisecretory and protective properties, promoting healing of gastric and duodenal ulcers. It also acts as a potent uterine stimulant.

Question 8

What are the indications for use of misoprostol in obstetrics and gynaecology? (2)

Answer 8

1. Termination of pregnancy following mifepristone (up to 49 day)
2. For induction of labour
3. For missed or incomplete miscarriage

Question 9

What is the recommended dose of misoprostol for missed/incomplete miscarriage?

Answer 9

Incomplete miscarriage = 600micrograms

Missed miscarriage = 800micrograms

Question 10

If misoprostol is being used to induce labour, what are the important safety risks involved?

Answer 10

Misprostol vaginal delivery system (Mysodelle) can cause excessive uterine tachysystole that may not respond to tocolytic treatment. (Tocolytic treatment can be administered as soon as it is removed)

Question 11

What are the contraindications for use of mysodelle (the misoprostol used for induction of labour)? (7)

Answer 11

1. Before 36 weeks gestation
2. Chorioamnionitis
3. Placenta previa
4. Unexplained vaginal bleeding
5. Fetal compromise
6. Uterine abnormality
7. Fetal malpresentation

Question 12

What are the side effects associated with use of misoprostol? (9)

Answer 12

1. Constipation
2. Diarrhoea
3. Dizziness
4. Flatulence
5. GI discomfort
6. Headache
7. Nausea
8. Rash
9. Vomiting

Question 13

What is clomifene used to treat?

Answer 13

Infertility in woman - can help stimulate ovulation

Question 14

What are the two uses for ulipristal acetate?

Answer 14

1. Emergency contraception

2. Shrink uterine fibroids prior to surgery

Question 15

What are the drugs that are used as tocolytics?

Answer 15

1. Atosiban
2. Ritodrine
3. Nifedipine
4. Indomethacin

Question 16

What receptor does atosiban act on?

Answer 16

It is an oxytocin receptor agonist

Question 17

What receptor does ritodrine act on?

Answer 17

Beta-agonist

Question 18

Why is ritodrine now out of favour?

Answer 18

It has a poor side effect profile, including tachycardia, headache, palpitations, and impaired glucose tolerance

Question 19

What type of drug is indomethacin?

Answer 19

An NSAID