prescribing in pregnancy Flashcards
what anti emetic was prescribes to thousands of women caused lots of babies to be born deformed?
thalidomide
what drugs dont pass the placenta?
Most drugs cross
-except large molecular weight drugs such as heparin
what drugs cross the placenta more quickly
small, lipid soluble drugs
what is affected when taking meds with morning sickness:
A- absorption
B- distribution
C- metabolism
D- elimination
A- Absorption
what occurs to plasma volume in pregnancy?
increases
what occurs to protein binding in pregnancy and what affect does this have?
Decreased protein binding
-this leads to increased free drug
what occurs to liver metabolism of certain drugs such as phenytoin in pregnancy?
increased liver metabolism of certain drugs
what occurs to elimination of renally excreted drugs in pregnancy and what affect does this have on GFR?
increase elimination of renally excreted drugs
-increased GFR in pregnancy
what occurs to BP in second trimester of pregnancy?
it drops and goes back up in 3rd trimester
what should be given to women for 3 months prior and first 3 months of pregnancy?
they should take folic acid 400mcg
why are pregnant women given folic acid?
to prevent neural tube defects and microcephaly in foetus
what time is the period of greatest teratogenic risk?
1st trimester especially between 4th and 11th week of pregnancy
what can occur if drug exposure in 2nd + 3rd trimester of pregnancy
-foetal intellectual impairment and behavioural abnormalities
-Growth of foetus may be affected
-Toxic effects on foetal tissue
what affect does taking opiates during pregnancy have on the foetus?
-can cause respiratory depression
-can cause neonatal abstincence syndrome (NAS) which is basically withdrawal
what affect does taking warfarin during pregnancy have on foetus and mother?
fetus= limb and facial defects
mother= risk of haemorrhage during labour
risks of taking SSRIs during pregnancy?
first trimester= congenital heart defects, congenital malformations (especially when taking paroxetine)
third trimester= persistent pulmonary hypertension in neonates
also may experience withdrawals
what changes are made to medication for epileptics who are pregnant
avoid valproate and phenytoin
higher dose of folic acid
what diabetic meds arent safe in pregnancy
sulfynurea
so convert this to insulin
what hypertensive meds should be used in pregnancy?
-labetalol
-methyldopa
what hypertension meds should be avoided in pregnancy?
ACEI/ ARB
1st line med for N+V in pregnancy?
cyclizine
1st line med UTI in pregnancy
Nitrofurantoin, cefalexin
in third trimester- trimethoprim
1st line med for pain in pregnancy
paracetamol
1st line med for heartburn in pregnancy
anti acids
does pregnancy increase risk of VTE?
yes by about 10x
what meds should pregnant women with significant 2 or more VTE risk receive?
LMWH (up to 7 days post partum as well)
2 or more of:
obesity
>35 years
smoking
>3 pregnancies
ceserean delivery
previous DVT
what are risks for VTE?
LMWH (up to 7 days post partum as well)
2 or more of:
obesity
>35 years
smoking
>3 pregnancies
ceserean delivery
previous DVT
treatment for venous thromboembolism in pregnancy?
LMWH
-avoid warfarin as this risks haemorrhage during delivery
difference between foremilk and hindmilk?
foremilk- protein rich
hindmilk- fat rich
what can amiodarone cause if passed through breast milk?
neonatal hypothyroidism
what can cytotoxics cause if passed through breast milk?
bone marrow suppression
what can benzodiazepines cause if passed through breast milk?
drowsiness
what can bromocriptine cause if passed through breast milk?
suppress lactation
treatment?
give LMWH
-ideally teach her how to inject herself each day
tetracycline
-can give staining of bones and teeth (avoid in pregnancy and children up to 12 years)
alcohol
-this is fetal alcohol syndrome
phenytoin
-cleft lip and palate
(vaginal adenocarcinoma)
stillbestrol
Valproate
-causes neural tube defects (spina bifida on left)
what med should be taken for RA in pregnancy?
stop methotrexate
-start hydroxychloroquine
what changes are there to the mum in pregnancy?
-Increased plasma volume + fat stores
-increased liver metabolism for some drugs
-decreased protein binding (due to lower albumin levels)
what does increased plasma volume and fat stores lead to?
increases the volume of distribution around body (higher dose of drug is required to achieve a given plasma concentration)
what does increased liver metabolism to certain drugs do?
puts more stress onto liver
why are there decreased levels of albumin ?
due to higher overall volume
what does decreased protein binding do to the body? (this is due to lower albumin levels)
it means that there is more free drug circulating the body
who is at higher risk of neural tube defects and require + mg of folic acid?
-previous NTD
-taking anti epileptics
-Coeliac disease
-Diabetes
-Thalassaemia trait
-BMI >30 (obese)
what medication is given for pain?
paracetamol
who is given 400ug folic acid?
every pregnant woman until 12th week
