Pharmacology during pregnancy Flashcards
why might a woman be on medication during pregnancy?
epilepsy athsma hypertension long term anticoagulant therapy use i.e. atrial fibrillation diabetes mental health disorders migraine
how does oestrogen and progesterone have an effect on metabolism and why?
they can increase or decrease metabolism as they can induce or inhibit liver P450 enzymes
is the excretion of drugs increased or decreased during pregnancy and why?
excretion is increased due to increased GFR
therefore reduces plasma concentration and the need of a higher dose of renal excreted drugs
what factors determine placental transfer of drugs?
molecular weight (smaller sizes cross more easily)
polarity (non-polar cross more easily
lipid solubility
at what molecular weight does drugs cross the placenta?
<500 Da
when is risk of teratogenicity at highest?
first trimester
organogenesis (3-8 weeks)
when is fetotoxicity highest?
2nd and 3rd trimester
give examples of drugs which cause folate antagonism?
methotrexate trimethoprim carbamezapine phenytoin valproate
what are the 2 processes that cause folate antagonism?
block the conversion of folate to THF by binding irreversibly to the enzyme
block other enzymes in the pathway
what defects odes folate antagonism result in?
neural tube
limbs
oro-facial
what sort of problems can neural crest cell destruction cause and what drugs cause this?
retinoids i.e. isotretinoin
aortic arch anomalies ventricular septal defects craniofacial malformations oesophageal atresia pharyngeal gland abnormalities
what damage can NSAIDS cause to foetal development ?
orofacial clefts
cardiac septal defects
premature closing of ductus arteriosus
give examples of fetotoxicity complications.
growth retardation structural malformations
foetal death
functional development
carcinogenesis
what effects does ACE inhibitors cause?
renal damage
growth restrictions
what effects can warfarin cause?
haemorrhage in the feats
malformations in CNS and skeletal system
what drugs cause premature closing of ductus arteriosius?
NSAIDS
what effect does valproate, carbamazepine and phenytoin cause?
neural tube defect
what drugs should you avoid when breast feeding?
cytotoxics immunosuppressants anti-convulsants amiodarone lithium radio-iodine
what are the effects of isotretinoin in pregnancy?
aortic arch anomalies craniofacial anomalies ventricular septal defects pharyngeal gland anomalies oesophageal atresia
what is the most critical period in pregnancy when you should avoid all medications if possible?
first 10 weeks
is trimethoprim ok to prescribe in pregnancy to treat UTI?
yes but avoid in first trimester
if a mother is breast feeding and is requring medication for pain relief, what can she safely take?
paracetamol
ibuprofen (some say not to use it)
codeine (not harmful but mother metabolism is variable so risk of morphine OD in baby)
if the mother is epileptic and takes a seizure during pregnancy, what consequence can this have on the baby?
foetal hypoxia
what complications can warfarin have on the foetus?
reduces vitamin K levels therefore clotting factors
congenital heart defects
problems with bones
growth restriction
