Prescribing in Pregnancy Flashcards
what was the drug used for morning sickness that caused lots of death and deformities in babies
thalidomide
what drugs cross the placenta
most
except large molecular weight heparin
small, lipid soluble cross more quickly
how can pharmacokinetics be affected in pregnancy
Absorption may be affected by morning sickness
Increased plasma volume and fat stores
(Volume of distribution increases)
Decreased protein binding
(Increased free drug)
Increased liver metabolism of some drugs
(Phenytoin)
Elimination of renally excreted drugs increases
Increased GFR
what drugs should you monitor doses during pregnancy and after delivery
lithium, digoxin
name a drug pregnant women are more sensitive to
can get hypotension with antihypertensives in 2nd trimester
what drug should be taken pre conception
Folic acid 400mcg daily for 3 months prior and first 3 months of pregnancy
what else needs to be done preconception
review drugs of chronic conditions, choose safest options/ decide if treatment necessary
what is the period of greatest teratongenic risk
4-11th week in 1st trimester:
risk of miscarriage, organogenesis
what is the general rule for prescribing in 1st trimester
Avoid drugs if at all possible unless maternal benefit outweighs risk to foetus
name 8 teratogenic drugs
ACE inhibitors/ARB Androgens Antiepileptics Cytotoxics Lithium Methotrexate Retinoids Warfarin
what can ACEis/ ARBs cause
Renal hypoplasia
what can androgens cause
Virilisation of female foetus
what can antieplieptics cause
Cardiac, facial, limb, neural tube defects
what can cytotoxics cause
Multiple defects, abortion
what can lithium cause
Cardiovascular defects
what can methotrexate cause
Skeletal defects
what can retinoids cause
Ear, cardiovascular, skeletal defects
what can warfarin cause
Limb and facial defects
what is at risk in 2nd and 3rd trimester
Growth of foetus Functional development -Intellectual impairment -Behavioural abnormalities Toxic effects on foetal tissue
name a drug that causes developmental disorders due to affecting foetus in 2nd and 3rd trimester
sodium valproate
what drug can suppress the foetal resp system during labour
opiates
what drugs can cause withdrawal effect on foeuts after birth
opiates, SSRI
what does diethylstilbestrol cause
vaginal adenocarcioma in F and urological malignancy in M in patients whose mothers were exposed (delayed effect of the drug)
what should be done to prevent VTE in pregnancy
all should be encouraged to stay mobilised and hydrated
those with significant risk factors should receive thromboprophylaxis with LMWH at delivery and up to 7 days post partum
what constitutes significant risk of VTE
2 or more risk factors eg obesity, age>35yrs, smoking, para >3, previous DVT, Caesarean delivery
how do you treat suspected DVT or PE
theraputic dose LMWH
why should you avoid warfarin in pregnancy
teratogenic in early pregnancy
risk of haemorrhage during delivery if given during late pregnancy
what drugs enter breast milk
most especially small molecule and fat soluble (lipophilic) drugs
how can breast feeding patterns affect amount of drugs in milk
foremilk- protein rich
hind milk- higher fat content
longer feeds, higher amounts of fat soluble drugs in milk
why might drugs in breast milk accumulate in infant
immature metabolism
name a drug that is actively concentrated in breast milk
phenobarbitone (causes suckling difficulties)
what can amiodarone in breast milk cause
neonatal hypothyroidism
what can cytotoxics in breastmilk cause
bone marrow suppression
what can benzodiazepines in breastmilk cause
drowsiness
what can bromocriptine in pregnancy
can suppress lactation
should pregnant women take herbal remedies e.g. st john wort
should avoid - consider why she wants to take them, undiagnosed illness?
what hypertension drugs are considered safe in pregnancy
Labetalol or methyldopa
what are the golden rules to prescribing in pregnancy
Balance risk vs benefits
Treat if necessary
Safest drug, lowest effective dose, shortest possible time
what antibiotics given in pregnancy can cause staining of teeth and bones
tetracycline- also avoid in children under 12
what are the facial features of fetal alcohol syndrome
short palpebral fissures flat midface short nose indisctinct philtrum thin upper lip
when drug is associated with cleft lip and palate
phenytoin
what drug when taken in pregnancy causes vaginal adenocarcinoma in female offspring
stilbestrol
name 2 neural tube defects caused by valproate
spina bifida and anecephaly
