Prescribing in Pregnancy

Question 1

When, in pregnancy, does development of the limbs and organs occur?

Answer 1

Very early on

Question 2

What could be considered instead of antidepressants?

Answer 2

CBT

Question 3

If benefits outweigh risks …

Answer 3

Prescribe

Question 4

> ___% of women take drugs in pregnancy

Answer 4

90

Question 5

Do most drugs cross the placenta?

Answer 5

Yes

Question 6

What drugs don’t cross the placenta?

Answer 6

Drugs of large molecular weight e.g. heparin

Question 7

What type of drugs cross the placenta more quickly?

Answer 7

Small, lipid-soluble drugs

Question 8

What is pharmacokinetics?

Answer 8

What the body does to a drug – Absorption, Distribution, Metabolism, Elimination

Question 9

What may absorption of a drug be affected by?

Answer 9

Morning sickness

Question 10

What happens to volume of distribution during pregnancy?

Answer 10

Vd increases – due to increased plasma volume and fat stores

Question 11

What happens to level of free drug during pregnancy?

Answer 11

Increased free drug – due to decreased protein binding.

Question 12

What happens to liver metabolism of some drugs during pregnancy?

Answer 12

Increased liver metabolism of some drugs e.g. phenytoin.

Question 13

What happens to GRF during pregnancy?

Answer 13

Increased GFR – due to increased elimination of renally excreted drugs

Question 14

Give 2 examples of drugs for which the concentrations may need to be checked and the dose altered during pregnancy and after delivery.

Answer 14

• Lithium

* Digoxin

Question 15

What is pharmacodynamics?

Answer 15

What the drug does to the body

Question 16

What is the effect of pregnancy on pharmacodynamics?

Answer 16

Doesn’t cause any significant changes

Question 17

What is the effect of pregnancy on pharmacodynamics?

Answer 17

Doesn’t cause any significant changes

BUT, pregnant women may be more sensitive to some drugs

Question 18

When should folic acid be given and how much?

Answer 18

400mcg daily for 3 months prior and first 3 months of pregnancy

Question 19

What is there a risk of in the 1st trimester?

Answer 19

Miscarriage

Question 20

What is the important process that takes place during the 1st trimester?

Answer 20

Organogenesis.

Question 21

When is the period of greatest teratogenic risk?

Answer 21

4th -11th week

Question 22

What do ACEI’s/ARB’s do to the foetus?

Answer 22

Renal hypoplasia

Question 23

What do androgens do to the foetus?

Answer 23

Virilisation of the female foetus

Question 24

What do antiepileptics do to the foetus?

Answer 24

Cardiac, facial, limb, neural tube defects

Question 25

What do cytotoxic do to the foetus?

Answer 25

Multiple defects, abortion

Question 26

What does lithium do to the foetus?

Answer 26

CVS defects

Question 27

What does methotrexate do to the foetus?

Answer 27

Skeletal defects

Question 28

What do retinoids do to the foetus?

Answer 28

Ear, cardiovascular, skeletal defects.

Question 29

What does Warfarin do to the foetus?

Answer 29

Limb and facial defects

Question 30

What happens – in terms of foetal development – in the 2nd and 3rd trimesters?

Answer 30

• Growth of foetus.

* Functional development: intellectual impairment; behavioural abnormalities.

Question 31

Give examples of how drugs taken around term may have adverse effects on labour.

Answer 31

• Slow progress of labour.
• Adaptation of foetal circulation may be affected – premature closure of ductus arteriosus.
• Suppression of foetal systems – opiates cause respiratory depression.
• Bleeding – warfarin.

Question 32

What adverse effect on baby after delivery may occur if drugs are taken around term?

Answer 32

• Withdrawal syndrome – opiates, SSRI.

* Sedation.

Question 33

What is Diethylstilbestrol used for?

Answer 33

Prevention of recurrent miscarriage (didn’t actually work) from 1940-1971.

Question 34

In what % of women do seizures increase during pregnancy? Why?

Answer 34

10%.

• non-compliance.
• changes in plasma concentrations of drugs: persistent vomiting, increased clearance.