adverse drug reactions Flashcards
who is most likely to get an ADR?
elderly
multi morbid (renal/hepatic clearance)
polypharmacy
which drugs have a narrow therapeutic index?
warfarin
lithium
digoxin
gentamicin
vancomycin
cyclosporin
levothyroxine
what does a narrow therapeutic index mean?
a narrow dose in which the drug is effective
what is involved in phase 1 of drug metabolism?
oxidation, reduction and hydrolysis
what is involved in phase 2 of drug metabolism?
conjugation
(enables excretion in urine)
are ADRs usually due to phase1 or phase 2?
phase 1
what are some type A ADRs?
pre renal failure
- Diuretics (HF, dehydration)
- Acei/ARBs (D+V)
renal (Tubular necrosis)
- gentamicin (sepsis)
sulphonamides (RA)
aspirin (CV disease)
what is a type A ADR?
dose dependent and predictable
- augmented pharmacologic affects
what are some causes of type A ADRs?
drug-drug (eg ACEi and sulphonylureas or clopidogrel and PPIs)
drug-disease
drug-food
what is a type B reaction?
dose independent and unpredictable
have a high mortality
what are some examples of type B reactions?
drug rashes
bone marrow aplasia
hepatic necrosis
what kind of ADR is type C
chronic
need monitoring
can be anticipated but patient must be warned before starting therapy
what are some examples of a type C reaction?
steroid therapy-cushings
B blockers- diabetes
NSAIDs- hypertension
what kind of ADR is type D?
delayed
can occur many years after stopping
teratogenic/carcinogenic affects
less frequent now due to rigorous pre clinical testing
what are some examples of type D?
secondary malignancies post chemo
craniofacial abnormalities in children of women taking isotretinoin
what are type E ADRs?
caused by abrupt withdrawal
rebound effects
what are some examples of type E reactions?
beta blocker withdrawal and angina
steroid withdrawal and addisonian crisis
what does the black triangle mean in the BNF?
usually new medicines that have a new active ingredient
biologics/vaccines
status reviewed after 10 years and only removed when safety established
