Adverse Drug Reactions Flashcards
what is an adverse drug reaction
Adverse drug reaction= any undesirable drug reaction, whether expected, predictable or not that results in a detriment to the wellbeing of the patient in any way- whether symptomatic, detectable or not in the absence of another biologically plausible explanation that can be proven (not same as side effect)
who is more likely to get ADRs
elderly/ frail
mutlimorbid (renal/ hepatic clearance)
polypharmacy
what is the theraputic index formula
toxic dose 50/ effective dose 50
name 10 drugs will a narrow theraputic window
warfarin vancomycin lithium digoxin gentamicin phenytoin cyclosporin carbamazepine theophylline levothyroxine
what happens in phase 1 of drug metabolism
usually through cyp p450
oxidation, reduction and hydrolysis
when must ADRs happen
what happens in phase 2 of drug metabolism
coagulation (making it water soluble) so it can be excreted in urine/ bile
what is a type A ADR
dose dependent and predictable (higher doses more likely to cause ADRs)
what are the type A drug reaction in drugs used for pre renal failure
hypotension and hypovolaemia caused by:
- duiretics (cause dehydration)
- ACEi/ ARBs (cause D&V)
what drugs can cause acute interstitial necrosis/ tubular necrosis via type A ADRs
gentamicin
sulphonamides (used in RA)
aspirin (for CVD)
what drugs can cause retroperitoneal fibrosis, cyrstaluria, urinary calculi
methysergide (used for cluster headaches)
chemotherapy
drug drug interactions:
theophylline and
macrolides
drug drug interactions:
statins and
macrolides
or
fibrates
drug drug interactions:
tricyclic antidepressants and
type 1 anti arrhythmic drugs (ST/ vent repolarisation)
drug drug interactions:
warfarin and
lots of drugs
drug drug interactions: what can ACEi increase the hypoglycaemic effects of
sulphonylureas
drug drug interactions:
clopidogrel and
PPIs
what are the different types of drug interactions
drug drug
drug herbal
drug disease
drug food
what can grapefruit interact with
inhibits cyp p450 (breaks down simvastatin) so increases simvastatin levels
drug herbal interactions: ginko biloba (for dementia) saw palmetto (for BPH)
act as anticoagulant
drug herbal interactions: saw palmetto (for BPH)
act as anticoagulants
drug herbal interactions:
glucosamine for OA
causes hyperglycaemia and is an anticoagulant
drug herbal interactions:
ST johns wort (for depression)
reduces the effectiveness of the combined oral contraceptive pill
drugs disease interactions:
patients with parkinsons
have increased risk of drug induced confusion
drugs disease interactions:
NSAIDs/ COX 2/ TSDs
can exacerbated CHF as all cause sodium retention
drugs disease interactions:
urinary retention in BPH is more likely in patients on…
decongestants or anticholingerics
what drugs worsen constipation
calcium, anticholinergics, CCBs
what drugs lower seizure thresholds
neuroleptics, tramadol and quinolones
what drugs must you NEVER give in patients with poorly controlled epilepsy
neuroleptics, tramadol or quinolones
drugs disease interactions:
asthma and
beta blockers (especially if not specific to beta 1 receptors) can cause bronchoconstriction
drug food interactions:
bananas, oranges, green leafy veg
all these high in potassium
interact with ACEi. ARBs and K sparing duiretics as these cause hyperkalaemia
drug food interactions:
apples, chickpeas, spinach, nuts, kiwi and brocolli
high in vit E and vit K
interact with warfarin
drug food interactions:
chicken, turkey, milk, soy, cheese and yoghurt
alter body’s pH
affect absorption of antibiotics, thyroid meds, digoxin, diuretics
drug food interactions:
grapefruit, apple, orange, cranberry
have cytochrome p450
interact with statins and antihistamines
what are type B ADRs- give 3 examples
bizarre effects, dose independent and unpredictable
e.g. drug rashes, bone marrow aplasia (chloramphenicol antibiotic), hetaptic necrosis (halothane)
do type B ADRs have a high mortality
yes very high
what are type C ADRs, give 3 examples
chronic in prolonged treatment e.g steroids= cushing beta blockers= diabetes NSAIDs= hypertension (fluid retention)
what must be done in type A drug reactions
dont dismiss patients with strange side effects from drugs that arent expected
what should be done in type C ARDs
emphasise drug monitoring, must warn patient before starting drug
what are type D ADRs give 2 examples
delayed- remote form treatment/ often many years after stopping therapy
e.g.
tetratogenc/ carinogenic effects from chemo
isoretinoin (for acne) can cause craniofacial abnormalities in babies
what must be done for type D ADRS
rigorous pre clinical assessment
what is a type E ADR give 3 examples
end of treatment - due to abrupt withdrawal, rebound effect
e.g.
beta blockers= angina and rebound tachycardia
steroids= addisonian crisis
anticonvulsants= changes in epilepsy frequency
what is a type F ADR
failure of theraputic treatment
what does the black triangle in the BNF mean
new medicine that have new active ingredient so have to be very vigilant to any SE and fill in yellow card report. Black triangle removed when safety established
when do you fill in yellow cards
when your patient has an unexpected SE even is only suspected that drug is causing it
