Prescribing in Pregnancy

Question 1

What pregnancy related factors may influence pharmacokinetics?

Answer 1

Absorption:
morning sickness

Distribution:
increased PV and fat stores
decreased protein binding (so increased free drug)

Metabolism:
Increased liver metabolism

Elimination:
Increased GFR

Question 2

When during pregnancy is the greatest teratogenic risk?

Answer 2

4th-11th week

Question 3

What are the teratogenic effects of ACEis/ARBs?

Answer 3

Renal hypoplasia

Question 4

What are the teratogenic effects of androgens?

Answer 4

Virilisation of female foetus

Question 5

What are the teratogenic effects of antiepileptics?

Answer 5

Cardiac, facial, limb and neural tube defects

Question 6

What are the teratogenic effects of cytotoxics?

Answer 6

Abortion + others

Question 7

What are the teratogenic effects of lithium?

Answer 7

Cardiovascular

Question 8

What are the teratogenic effects of methotrexate?

Answer 8

Skeletal

Question 9

What are the teratogenic effects of retinoids?

Answer 9

Ear, cardiovascular and skeletal

Question 10

What are the teratogenic effects of warfarin?

Answer 10

Limb and facial defects

Question 11

What kinds of problems can occur to the foetus if affected by drugs in the 2nd and 3rd trimesters?

Answer 11

Growth problems
Intellectuel impairment
Behavioural abnormalities

Question 12

If possible, which epileptic drugs should especially be avoided in pregnancy?

Answer 12

Valproate

Phenytoin

Question 13

What preventative measures can be taken by pregnant women on anti-epileptics?

Answer 13

Folic acid 5mg daily

Question 14

Which diabetic drug class is contraindicated in pregnancy?

Answer 14

Sulphonylureas

Question 15

Which hypertensive drugs are generally used in pregnancy?

Answer 15

Labetalol
Methyldopa
Nifedipine MR

Question 16

Which antihypertensives should be avoided in pregnancy?

Answer 16

ACEis/ARBs 
Beta Blockers (esp in late pregnancy)

Question 17

How should N+V in pregnancy be treated?

Answer 17

Cyclizine

Question 18

How should UTI in pregnancy be treated?

Answer 18

Nitrofurantoin

3rd trimester = trimethoprim

Question 19

Which drugs cause problems in breastfeeding?

Answer 19

Phenobarbitone: suckling problems 
Amiodarone: neonatal hypothyroidism 
Cytotoxics: bone marrow suppression 
Benzodiazepines: drowsiness 
Bromocriptine: surpasses lactation

Question 20

Which antidepressant can increase the risk of foetal heart defects in the first trimester?

Answer 20

Paroxetine

Question 21

Which antidepressants should be avoided in breastfeeding?

Answer 21

Citalopram

Doxepin

Question 22

What is the risk of using benzodiazepines in the third trimester?

Answer 22

Floppy baby syndrome

Hypothermia, hypotonia, respiratory depression, withdrawal

Question 23

Which antipsychotic should be avoided in pregnancy at all time due to increased risk of agranulocytosis?

Answer 23

Clozapine

Question 24

What are the risks of olanzapine during pregnancy?

Answer 24

Gestational diabetes

Weight gain

Question 25

What is the risk of lithium in the first trimester?

Answer 25

Ebstein’s abnormality

Question 26

What is the advice re lithium and breastfeeding?

Answer 26

Avoid when breastfeeding

If not breastfeeding, consider prophylactic reintroduction soon after delivery (this may be better long term)