Prescribing in Pregnancy

Question 1

most drugs cross the placenta, except what?

Answer 1

large molecular weight eg heparin

Question 2

what type of drugs cause the placenta more quickly?

Answer 2

small, lipid-soluble drugs

Question 3

absorption of drugs may be effected by what condition which commonly occurs in pregnancy?

Answer 3

morning sickness

Question 4

other than absorption, how else can pregnancy affect the pharmacokinetics of a drug?

Answer 4

increased PV and fat stores so volume of distribution increases

decreased protein binding so increased free drug

increased liver metabolism of some drugs eg phenytoin

elimination of renally excreted drugs increases due to increased GDR

Question 5

what kind of drugs can pregnancy women be more sensitive to?

Answer 5

antihypertensives - get hypotension in 2nd trimester

Question 6

what is the recommended dose of folic acid?

Answer 6

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

Question 7

what trimester of pregnancy has greatest teratogenic risk?

Answer 7

1st (4th to 11th week)

*avoid drugs if at all possible unless maternal benefit outweighs risk of foetus

Question 8

what foetal defects can be caused by the following teratogenic drugs:

a) ACE inhibitors / ARB
b) androgens
c) anti-epileptics
d) cytotoxics
e) lithium
f) methotrexate
g) retinoids
h) warfarin

Answer 8

a) renal hypoplasia
b) virilisation of female foetus
c) cardiac, facial, limb and neural tube defects
d) multiple defects, abortion
e) CV defects
f) skeletal defects
g) ear, cardiovascular and skeletal defects
h) limb and facial defects

Question 9

what type of development can teratogenic drugs impair in 2nd and 3rd trimester?

Answer 9

intellectual impairment

behavioural abnormalities

Question 10

what drug can cause the suppression of foetal systems?

Answer 10

opiates - respiratory depression

Question 11

what drugs can cause withdrawal syndrome in babies?

Answer 11

opiates

SSRIs

Question 12

why do 10% of epileptic pregnant women experience increased in seizures?

Answer 12

non-compliance

changes in plasma concentrations of drugs eg persistent vomiting and increased clearance

Question 13

frequent seizures during pregnancy are thought to cause what conditions?

Answer 13

lower verbal IQ in child
hypoxia 
bradycardia 
antenatal death 
maternal death

Question 14

what antiepileptics should you avoid in pregnancy?

Answer 14

valproate

phenytoin

Question 15

how much folic acid should epileptic pregnant women take?

Answer 15

5mg

Question 16

what type of diabetic medication is thought to be unsafe in pregnancy?

Answer 16

sulfonylureas

*convert to insulin

Question 17

if you do need to treat hypertension, you should use one of what three drugs?

Answer 17

labetalol
methyldopa
(nifedipine MR)

• avoid ACE inhibitors / ARBs
• beta blockers may inhibit foetal growth in late pregnancy

Question 18

what is the safest drug for nausea and vomiting in pregnancy?

Answer 18

cyclizine

Question 19

what drugs should be used for UTI in pregnancy?

Answer 19

nitrofurantoin

3rd trimester - trimethoprim

Question 20

what drug should be used for pain in pregnancy?

Answer 20

paracetamol

Question 21

what drug should be used for heartburn in pregnancy?

Answer 21

antacids

Question 22

what is the leading cause in maternal death in pregnancy and therefore all pregnant women should be risk assessed for it?

Answer 22

VTE

Question 23

women with significant risk factors for VTE should receive prophylaxis with what treatment?

Answer 23

LMWH

*2 or more risk factors eg obesity, >35yo, smoking, para>3, previous DVT, C section

Question 24

which drugs can affect babies through breastfeeding?

Answer 24

phenobarbitone - suckling difficulties 
amiodarone - neonatal hypothyroidism
cytotoxics - bone marrow suppression 
benzos - drowsiness
bromocriptine - suppresses lactation

Question 25

which antibiotic given during pregnancy or early childhood can cause staining of bones and teeth?

Answer 25

tetracycline

*avoid in children up to age 12

Question 26

which drug taken in excess in early appearance can cause the following features: short palprebral fissures, flat midface, short nose, indistinct philtrum, thin upper lip?

Answer 26

alcohol

Question 27

which antiepileptic drug is particularly associated with cleft lip and palate?

Answer 27

phenytoin

Question 28

which drug taken during pregnancy can cause vaginal adenocarcinoma in female offspring?

Answer 28

stillbestrol

Question 29

which antiepileptic drug is particularly associated with neural tube defects such as spina bifida and anencephaly?

Answer 29

valproate