drugs during pregnancy

Question 1

organogenesis

Answer 1

17-70 days

major birth defects in various organ systems

Question 2

category A

Answer 2

taken by many pregnant women without any proven increase in the frequency of malformations

Question 3

category C

Answer 3

have caused or may be suspected of causing effect on the human neonate which may be reversible, does not cause malformations

Question 4

Category B1,2,3

Answer 4

have been taken by only a limited number of pregnant women and women of childbearing age
no harmful effects observed

Question 5

category D

Answer 5

increased evidence of human malformations or irreversible damage

Question 6

category X

Answer 6

such a high risk of causing permanent damage that they should not be used in pregnancy or when there is possibility of pregnancy

Question 7

pregnancy induced effects on drug pharmacokinetics

Answer 7

• increased body water and fat
• altered protein binding, lower albumin
• increased liver metabolism
• increased renal blood flow
• slower gastro-intestinal motility
• placental drug metabolism

Question 8

issues with drug taking in pregnancy

Answer 8

• poor oral compliance due to nausea and vomiting
• high dose requirements - antidepressants, anticonvulsants, lithium, penicillin, heparins) due to increased clearance
• lower dose requirements (transdermal drugs due high skin blood flow and more free drug unless highly protein bound

Question 9

analgesics usable in pregnancy

Answer 9

• use paracetamol
• low dose aspirin (avoid high dose)
• codeine (cat C)
• NSAIDs (cat C)

Question 10

issues with NSAIDs

Answer 10

first rimester use and early pregnancy loss increase
small risk of fatal harm from 27-32 weeks until delivery
- premature closure of the ductus arterioles and pulmonary hypertension
- necrotising enterocolitis
- renal failure
- neonatal intracranial haemorrhage

Question 11

opiod use in pregnancy

Answer 11

• probably safe in early pregnancy but possible potential for long term behavioural effects
• neonatal respiratory depression at birth
• neonatal withdrawal (abstinence syndrome)

Question 12

tramadol use in pregnancy

Answer 12

• no good trials or epidemiology so safety not established, but widely used

Question 13

gabapentin and pregabalin

Answer 13

safety not established but used

Question 14

clonidine

Answer 14

safe

Question 15

antiemetics

Answer 15

mtroclopramide 
5-HT antagonists 
droperidol 
promethazine 
prochlorperazine

Question 16

safe antibiotics

Answer 16

all penicillins 
early generation cephalosporins 
erythromycin 
clindamycin 
metronidazole

Question 17

possible risk antibiotics

Answer 17

sulphonamides and nitrofurantoins
aminoglycosides
anti-retrovirals

Question 18

cardiovascular drugs that are ok

Answer 18

methyldopa 
beta blockers (possibly avoid atenolol) 
calcium channel blockers 
hydralazine

Question 19

cardiovascular drugs to avoid

Answer 19

ACE inhibitors and ARBs (renal failure/fetal death)
amiodorone (hypothyroidism and bradycardia)
thiazide diuretics (cause neonatal electrolyte derangements)
spironolactone (feminisation of the male fetus)

Question 20

respiratory drugs

Answer 20

almost all ok
continue inhaled anti-asthma drugs
steroids are ok - caution with high dose

Question 21

diabetic drugs

Answer 21

risk of macrosomia, neonatal hypoglycaemia, congenital abnormalities

• sulphonylureas not recommended
• rosiigltazone not recommended
• metformin safe and widely used
• insulin recommended

Question 22

psychotropic drugs

Answer 22

risk from prescribing

• foetal death or abnormality, growth retardation
• neonatal toxicity, developmental defects

risk from not prescribing

• foetal abuse/neglect
• adverse neonatal care
• maternal distress, self harm, use of harmful substitutes, family deterioration

which ones can be used

• typical anti-psychotics probably ok except chlorpromazine
• atypical anti-psychotics unclear but limited data suggest OK
• avoid lithium if possible - causes birth defects

Question 23

tricyclic antidepressants

Answer 23

appear safe

imipramine and nortriptyline safe in early pregnancy

Question 24

SSRIs

Answer 24

appear safee

use in third trimester can lead to neonatal with drawl syndrome so reduce dose if possible

Question 25

anticonvulsants

Answer 25

risk of infants abnormalities
no drug of choice
not prescribing = seizures, fatal death and childhood IQ reduction
aim for mono therapy with most efficient drug at lowest dose
change drugs pre conception if possible
dose adjustment required

Question 26

anti-migraine drugs

Answer 26

sumatriptan - avoid

atenolol and propanolol - avoid

Question 27

anti-inflammatory and immunosuppressant drugs

Answer 27

prednisolone - avoid, cleft palate, continue if needed at lowest effective dose
hydroxychloroquine - avoid, neurological disturbance
azathioprine and cyclosporine - usually continue for organ transplant

Question 28

other drugs to avoid

Answer 28

cytotoxics
retinoids and interferon 
mycoophenolate and mofetil 
progestogens, danazol 
statins 
tetracyclines

Question 29

drug passage into milk

Answer 29

molecular weight, lipid solubility and ioonisation, protein binding
milk composition and volume changes in first days
intake is approx. 150mll/kg/day but dose and dose interval and sucking pattern also relevant

Question 30

RID

Answer 30

relative infant dose in breast milk
estimate absolute infant dose

drug conc in milk x volume of milk in 24 hours divided by maternal dose
expressed as a percentage

RID <10% of a drug that is largely free of serious side effects is considered acceptable

Question 31

infant exposure

Answer 31

conc in infant plasma ass a percentage of that in material plasma

Question 32

main drugs to avoid

Answer 32

• ace inhibitors
• warfarin - fetal loss, embryopathy, intracranial haemorrhage
• aminoglycosides and tetracyclines (use penicillin, erythromycin and cephalosporins)
• NSAIDs - use paracetamol, tramadol, short course opiods)
• ssulfoneureas (use insulin)
• amiodarone (use digoxin)
• sodium valproate (use lamotrigine) and phenytoin (use carbemazepine)