Adverse Drug Reactions Flashcards
What is an adverse drug reaction (ADR)
Any response to a drug which is noxious, unintended and occurs at doses used in man for prophylaxis, diagnosis or treatment
An appreciably harmful or unpleasant reaction
What does an ADR result in
An intervention related to the use of a medicinal product, which predicts hazard from future administration and warrants prevention or specific treatment, or alteration of the dosage regimen, or withdrawal of the product
How many people are admitted annually due to ADR’s
1,000,000 (6.5% of all hospital admissions)
How many inpatients suffer an ADR
10-20%
How many deaths a year are due to ADR
5000 - 12,000
What is the 4th leading cause of death
ADR
What type of onset can ADR show
Acute
Sub-acute
Latent
Describe acute ADR
Occur within 60 minutes (e.g. bronchoconstriction)
Describe sub-acute ADR
Occurs within 1 to 24 hours
Can present with rash and serum sickness
Describe latent ADR
Occurs after 2 days
May show eczematous eruptions
What are the three classes of severity of ADR
Mild
Moderate
Severe
Describe a mild ADR
It is bothersome but requires no change in therapy (e.g. metallic taste with metronidazole)
Describe a moderate ADR
It requires change in therapy, additional treatment and hospitalization (e.g. amphotericin induced hypokalemia)
Describe a severe ADR
Causes a disabling or life-threatening condition (e.g. kidney failure)
How are ADRs classified (6)
Type A - Augmented Type B - Bizarre Type C - Chronic Type D - Delayed Type E - End of treatment Type F - Failure of treatment
Describe a type A ADR
It causes normal but augmented response to the pharmacological actions of a drug
It is dose related and predictable
Describe a type B ADR
It causes Bizarre effects
It is idiosyncratic and unpredictable
What are predisposing factors to ADRs
Multiple Drug Therapy Inter-current Disease (e.g. renal and hepatic impairment) Race and Genetic Polymorphisms Age (e.g. elderly and neonates) Sex (e.g. ADRs more common in women)
What are type A ADRs due to
Excess pharmacological action (e.g.
Bradycardia with beta-blockers or Hypoglycaemia with sulphonylureas or insulin)
The secondary pharmacology of a drug unrelated to the therapeutic effect.
What type of ADR is the most common
Type A (account for 80% of all ADRs)
How can type A be treated
Its easily reversible by reducing the dose or stopping the drug
Not usually life threatening
What types of type A ADRs are there
Augmentation of the primary effect
Secondary effect
What are the reasons for a type A ADR
Too high a dose
Pharmaceutical variation
Pharmacokinetic variation
Pharmacodynamic variation
When do pharmacokinetic variation and pharmacodynamic variation occur
Normally due to a result of disease
What can pharmacokinetic variation involve
Absorption (e.g. dose, formulation, GI motility, first pass metabolism)
Distribution
Metabolism (e.g. enhanced or impaired hepatic function)
Elimination (e.g. renal disease, reduced GFR)