Adverse Drug Reactions Flashcards
What is the definition of an adverse drug reaction?
Any response to a drug which is unintended
What is an adverse drug event?
Any event that occurs when a patient is on medication
What are the different classifications of Onset?
Acute (within 60 minutes, bronchoconstriction)
Sub-acute (1-24 hours, rash, serum sickness)
Latent (more than 2 days Eczematous eruptions)
Describe Mild, Moderate and Severe classifications of severity of Adverse Drug Reactions
Mild - Bothersome but requires no change in therapy
Moderate - Requires change in therapy, additional treatment, hospitalization
Severe - Disabling or life-threatening
What are the classifications of ADR’s?
Type A - Augmented Type B - Bizarre Type C - Chronic Type D - Delayed Type E - End of treatment Type F - Failure of treatment
What are the predisposing factors to ADR’s?
Multiple drug therapy Age Sex Intercurrent Disease Race and genetic polymorphism
What causes type A reactions?
They are normal but augmented response to a drug
Due to excess pharmacological action
How do you resolve a type A drug reaction?
Resolve when the drug is stopped
What are the reasons for a a type A ADR?
Too high a dose Pharmeceutical variation (consistent brand of strand of drug needed for consistent treatment)
PHARMACOKINETIC VARIATION
PHARMACODYNAMIC VARIATION
Describe the ways Pharmacokinetic variation can arise
Absorption (dose, formulation, GI motility, First pass metabolism ) Distribution Metabolism (enhanced or impaired) Liver disease Elimination
How can your genetics alter metabolism of drugs?
Some drugs are metabolised via acetylation which is under genetic control
Slow metabolisers are prone to drug toxicity
What is the result of renal impairment?
Toxic levels may build up
What is the effect of cardiac failure on drug absorption?
Reduced drug absorption from the gut due to oedema
Poor renal perfusion and decreased GFR
Hepatic congestion
What are some of the reasons ADR’s are as a result of pharmacodynamic variation?
Natural variability in pharmacodynamic response
Disease states can seriously alter the response
Describe type B ADR’s
Bizarre, unpredictable, rare, cause serious illness or death
Are Type B ADR’s related to the does?
NO
What is the primary mechanism of a type B ADR?
Immunological - there is no correlation between the pharmacological action of the drug and the effects seen in the patient
When is a person more likely to suffer from a type B adverse reaction?
When macromolecules are used (proteins, vaccines, polypeptides)
If the patient suffers from asthma, excema
HLA (human leukocyte antigen, codes for the MHC protein) presence of particular HLA increases the risk of a type B reaction.
Why do two different people respond to drugs in different ways?
Genetic reasons (abnormalities can lead to abnormal and unpredicatable responses to drugs) Immunological reasons
What is type C ADR?
Related to the duration of treatment as well as the dose and does not occur in a single dose
Is type C ADR predictable?
Semi-predicatable
What are type D ADR’s?
They occur some time after treatment
Who is affected by Type D ADR’s?
The children of the treated patients
The treated patients themselves after the treatment has stopped
Give examples of type D delayed effects
Second cancers - for those treated with alkylating agents or immunosuppressive agents
Craniofacial malformations in children whose mothers were treated with isotretinoin
When to type E ADR’s occur?
When a drug treatment is stopped (especially suddenly)
What is meant by the rebound phenomena?
Occurs when the drug is suddenly withdrawn
What is a type F ADR?
Failure of therapy
Is a type F ADR dose related?
Yes
What is the frequent cause of a type F ADR?
Drug interacions
What are the risk factors of ADR?
Age (children and the elderly) Multiple Medications Multiple co-morbid conditions Inappropriate medication prescribing, use or monitoring End-organ dysfunction Altered physiology Prior history of ADR's Dose and duration of exposure Genetic predisposition
How are ADR’s reported?
Using the Yellow Card Scheme - Collects information on ADR’s
Medical device adverse incidents, defective/fake medicines
