ADR's Flashcards
What % of admission to hospital are ADR’s?
5%
What are type A ADR’s?
Predictable dose related effects
What are type B ADR’s?
Non predictable/bizarre long term effects
What are type A’s usually due to?
- A pharmacokinetic/pharmacodynamic abnormality
What does this pharmacodynamic or kinetic abnormality result in?
An excess pharmacological effect
What is an example of a type A ADR?
- Insulin induced hypoglycaemia
- Beta blocker induced bradycardia
What can be the reason for the pharmacoKINETIC variation in type A?
- Altered metabolism through disease or pharmacogenetics
- Drug - drug interactions
What can be the reason for the pharmacoDYNAMIC variation in type A?
- Hepatic disease
- Dehydration
What is the nature of type B ADR’s?
- Unpredictable
- Immunological
What are examples of delayed effects of type B
- Tardive dyskinesia (involuntary jerks of the face and trunk)
- Carcinogenesis
What are examples of ADR surveillance methods?
- Anecdotal reporting
- Voluntary reporting
- Intensive event recording
- Cohort studies
- Pop statistics
What percentage of inpatients get ADR’s?
10-20%
How many deaths result from ADR’s?
5000-10000
What are augmented ADR’s?
- Predictable
- Dose dependent
- Recognised before drug is available
When do augmented ADR’s resolve?
When the drug is stopped
What are bizarre ADR’s?
- Unpredictable
- Rare
- Unrelated to dose
What can bizarre ADR’s result in?
Death
What is an example of augmented ADR’s?
Galactorrhoea with domperidone
What are chronic ADR’s related to?
- Dose
- Length of treatment
Are chronic ADR’s predictable?
To a certain extent
What are delayed ADR’s?
- Occur years after treatment
- Can occur in the children of the patient
What is an example of a delayed ADR?
Cancer in immunosuppressed individuals
End of treatment ADR example?
Seizure after anti-epileptics are stopped
Example of a chronic ADR?
Latrogenic Cushings Disease
What is the mechanism of a pharmacodynamic interaction?
- Antagonistic
- Additive or synergistic interaction
- Interactions from changes in drug transport
- Interactions due to fluid and electrolyte disturbances
What is an additive/synergistic interaction?
Two drugs with the same pharmacological effect
What are the 4 mechanisms of pharmacokinetic interactions?
- Absorption
- Distribution
- Metabolism
- Elimination
When is an absorption pharmacokinetic interaction important?
- When the drugs have a short half life
- Rapid results needed
What is the distribution mechanism a result of?
Another drug displacing the bound drug to increase the bioavailability
What protects patients from distribution mechanisms usually?
Metabolism and excretion
What is the process of metabolic mechanisms of ADR’s?
The drug influences the metabolism of another
What drugs inhibit the Cytochrome P450 pathway?
- Cimetidine
- Ketoconazole
- Omeprazole
What is the elimination pathway
Changes to GFR or tubular secretion
What drugs inhibit excretion?
- Verepamil
- Digoxin
What factors may make it easier for patients to have drug drug interactions
- More drugs
- Age
- Critical illness
- Surgery
- Chronic underlying conditions
