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
