drugs during pregnancy Flashcards
organogenesis
17-70 days
major birth defects in various organ systems
category A
taken by many pregnant women without any proven increase in the frequency of malformations
category C
have caused or may be suspected of causing effect on the human neonate which may be reversible, does not cause malformations
Category B1,2,3
have been taken by only a limited number of pregnant women and women of childbearing age
no harmful effects observed
category D
increased evidence of human malformations or irreversible damage
category X
such a high risk of causing permanent damage that they should not be used in pregnancy or when there is possibility of pregnancy
pregnancy induced effects on drug pharmacokinetics
- increased body water and fat
- altered protein binding, lower albumin
- increased liver metabolism
- increased renal blood flow
- slower gastro-intestinal motility
- placental drug metabolism
issues with drug taking in pregnancy
- 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
analgesics usable in pregnancy
- use paracetamol
- low dose aspirin (avoid high dose)
- codeine (cat C)
- NSAIDs (cat C)
issues with NSAIDs
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
opiod use in pregnancy
- probably safe in early pregnancy but possible potential for long term behavioural effects
- neonatal respiratory depression at birth
- neonatal withdrawal (abstinence syndrome)
tramadol use in pregnancy
- no good trials or epidemiology so safety not established, but widely used
gabapentin and pregabalin
safety not established but used
clonidine
safe
antiemetics
mtroclopramide 5-HT antagonists droperidol promethazine prochlorperazine
safe antibiotics
all penicillins early generation cephalosporins erythromycin clindamycin metronidazole
possible risk antibiotics
sulphonamides and nitrofurantoins
aminoglycosides
anti-retrovirals
cardiovascular drugs that are ok
methyldopa beta blockers (possibly avoid atenolol) calcium channel blockers hydralazine
cardiovascular drugs to avoid
ACE inhibitors and ARBs (renal failure/fetal death)
amiodorone (hypothyroidism and bradycardia)
thiazide diuretics (cause neonatal electrolyte derangements)
spironolactone (feminisation of the male fetus)
respiratory drugs
almost all ok
continue inhaled anti-asthma drugs
steroids are ok - caution with high dose
diabetic drugs
risk of macrosomia, neonatal hypoglycaemia, congenital abnormalities
- sulphonylureas not recommended
- rosiigltazone not recommended
- metformin safe and widely used
- insulin recommended
psychotropic drugs
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
tricyclic antidepressants
appear safe
imipramine and nortriptyline safe in early pregnancy
SSRIs
appear safee
use in third trimester can lead to neonatal with drawl syndrome so reduce dose if possible
anticonvulsants
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
anti-migraine drugs
sumatriptan - avoid
atenolol and propanolol - avoid
anti-inflammatory and immunosuppressant drugs
prednisolone - avoid, cleft palate, continue if needed at lowest effective dose
hydroxychloroquine - avoid, neurological disturbance
azathioprine and cyclosporine - usually continue for organ transplant
other drugs to avoid
cytotoxics retinoids and interferon mycoophenolate and mofetil progestogens, danazol statins tetracyclines
drug passage into milk
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
RID
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
infant exposure
conc in infant plasma ass a percentage of that in material plasma
main drugs to avoid
- 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)
