Adverse Drug Reactions Flashcards
what is an adverse drug reaction?
any response to a drug which is noxious/harmful, unintended and occurs at doses used in man for prophylaxis (preventing), diagnosis or treatment, relates to intervention of the use of the medical product
what is an acute onset of adverse drug reaction?
- occurs within 60 minutes
- bronchoconstriction (constriction of airway)
what is a sub-acute onset of adverse drug reaction?
- occurs from 1-24 hours
- rash, serum sickness
what is a latent onset of adverse drug reaction?
- after >2 days
- eczematous eruptions
what 3 categories can an onset of adverse drug reactions be split into?
- acute
- sub-acute
- latent
what 3 categories can severity of adverse drug reaction be split into?
- mild
- moderate
- severe
what is mild severity of drug reaction?
- bothersome but requires no change in therapy
e. g. metallic taste with metronidazole
what is moderate severity of drug reaction?
- requires change in therapy and additional treatment
- hospitalisation
(e. g. amphotericin induced hypokalemia)
what is severe severity of a drug reaction?
- disabling or life threatening
e. g. kidney failure
What is type A ADR?
augmented;
- dose related
- predictable
what is type B ADR?
bizarre;
- idiosyncratic (distinct, individual) and unpredictable
- also included Types C,D and E
what is type C ADR?
Chronic
what is type D ADR?
Delayed
what is type E ADR?
End of treatment
what is type F ADR?
failure of treatment
what are the 5 main predisposing factors to ADRs?
- multiple drug therapy
- age (elderly and neonates)
- sex (more common in women)
- intercurrent disease (e.g. renal or hepatic impairment)
- race and genetic polymorphisms
what are properties of Type A (augmented) reactions?
- normal response
- predictable and dose dependant
- due to excess pharmacological action
(e. g. bradycardia with beta blockers) - can be due to property of drug
- resolve when drug is reduced/stopped
- recognised before a drug is available
what are the reasons for Type A ADRs?
-pharmacokinetic variation
-pharmacodynamic variation
-too high a dose
-pharmaceutical variation
(pharmacological variation occurs as a result of disease)
what is absorption of a drug highly dependent on in pharmacokinetic variation? (5)
- dose
- formulation
- GI motility
- first pass metabolism
- therapeutic failure
- distribution
- metabolism (hepatic; either enhanced or impaired)
- elimination (renal)
what is especially important to consider if a drug has a narrow therapeutic index?
liver function (or disease)
what is pharmacogenetic factor?
- under genetic control; such as acetylation which is used for metabolism of many drugs
- prone to drug toxicity
what 3 disease especially have a huge role in ADRs and need to be monitored?
- renal impairment (build up of toxins if less excretion)
- hepatic impairment (toxin build up if no metabolism)
- cardiac failure (if oedema from circulation, then no drug reabsorption)
what is meant by pharmacodynamic variation?
- natural variability in response
- disease states can alter response significantly
what are the properties of type B (bizarre) ADRs?
- bizarre and unpredictable
- rare
- cause serious illness or death
- unidentified for months or years
- unrelated to the dose
- can be stopped by medicine/ stopper drug
- delay between exposure and ADR
