Prescribing in Pregnancy Flashcards
most drugs cross the placenta, except what?
large molecular weight eg heparin
what type of drugs cause the placenta more quickly?
small, lipid-soluble drugs
absorption of drugs may be effected by what condition which commonly occurs in pregnancy?
morning sickness
other than absorption, how else can pregnancy affect the pharmacokinetics of a drug?
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
what kind of drugs can pregnancy women be more sensitive to?
antihypertensives - get hypotension in 2nd trimester
what is the recommended dose of folic acid?
400mcg daily for 3 months prior and first 3 months of pregnancy
what trimester of pregnancy has greatest teratogenic risk?
1st (4th to 11th week)
*avoid drugs if at all possible unless maternal benefit outweighs risk of foetus
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
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
what type of development can teratogenic drugs impair in 2nd and 3rd trimester?
intellectual impairment
behavioural abnormalities
what drug can cause the suppression of foetal systems?
opiates - respiratory depression
what drugs can cause withdrawal syndrome in babies?
opiates
SSRIs
why do 10% of epileptic pregnant women experience increased in seizures?
non-compliance
changes in plasma concentrations of drugs eg persistent vomiting and increased clearance
frequent seizures during pregnancy are thought to cause what conditions?
lower verbal IQ in child hypoxia bradycardia antenatal death maternal death
what antiepileptics should you avoid in pregnancy?
valproate
phenytoin
how much folic acid should epileptic pregnant women take?
5mg
what type of diabetic medication is thought to be unsafe in pregnancy?
sulfonylureas
*convert to insulin
if you do need to treat hypertension, you should use one of what three drugs?
labetalol
methyldopa
(nifedipine MR)
- avoid ACE inhibitors / ARBs
- beta blockers may inhibit foetal growth in late pregnancy
what is the safest drug for nausea and vomiting in pregnancy?
cyclizine
what drugs should be used for UTI in pregnancy?
nitrofurantoin
3rd trimester - trimethoprim
what drug should be used for pain in pregnancy?
paracetamol
what drug should be used for heartburn in pregnancy?
antacids
what is the leading cause in maternal death in pregnancy and therefore all pregnant women should be risk assessed for it?
VTE
women with significant risk factors for VTE should receive prophylaxis with what treatment?
LMWH
*2 or more risk factors eg obesity, >35yo, smoking, para>3, previous DVT, C section
which drugs can affect babies through breastfeeding?
phenobarbitone - suckling difficulties amiodarone - neonatal hypothyroidism cytotoxics - bone marrow suppression benzos - drowsiness bromocriptine - suppresses lactation
which antibiotic given during pregnancy or early childhood can cause staining of bones and teeth?
tetracycline
*avoid in children up to age 12
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?
alcohol
which antiepileptic drug is particularly associated with cleft lip and palate?
phenytoin
which drug taken during pregnancy can cause vaginal adenocarcinoma in female offspring?
stillbestrol
which antiepileptic drug is particularly associated with neural tube defects such as spina bifida and anencephaly?
valproate
