Adverse Drug Reactions Flashcards
How many hospital admissions are as a result of an ADR
- 3.6% of hospital admissions are the result of an ADR
How long are patients who suffer an ADR likely to stay in hospital
- patients who suffer an ADR are likely to stay in hospital for over twice as long as those who do not
How much do ADRs cost the NHS
- cost the NHS around 600 million every year
What does rhabdomylsis look like
- rare, acute and potentially fatal muscle condition that results from the destruction of muscle cell membranes and the release of intracellular contents
- muscle swelling, tenderness and wekaness
- urine is grey to brown due to myoglobin
- CK is raised - usually by up to 10-100 times the normal limit
- associated with renal failure because myoglobin precipitates in the renal tubules
- associated with hyperkalemia because potassium is released when muscle cells. break down - this can be fatal
what can cause rhabdomyolysis
- increased age
- female sex
- pre-existing renal impairment
- high dose
- combination of statins with dilitiazem which inhibits the metabolism of statins by inhibiting cytochrome P450 isoenzyme
What is the maximum recommended dose of simvastatin with dilitiazem or amlodipine
20mg per day in order to prevent toxicity
what should you do in rhabdomylosis
- stop the statin
- if renal failure is established consider urgent dialysis
- IV fluids to prevent renal failure
- consider sodium bicarbonate to alkalinize the urine and reduce the precipitation of myoglobin in the renal tubules
- monitor serum potassium concentration and correct if necessary
How do you define an adverse drug reaction
- Use of a medicinal product within the terms of marketing authorisation as well as from use outside the terms of marketing authroisation including overdose, misuse, abuse and medication errors and suspected adverse reactions associated with occupational exposure
What is an adverse event
- is any harmful of unpleasant event that the patient experiences while using a drug whether or not it is related to the drug
What is an adverse drug reaction
- This is an adverse event where it is suspected to be caused by the drug
All ADRs are
All ADRs are adverse events but not all adverse events are ADRs
What is a type A ADR
Reactions that are generally
- dose related
- common, predictable
- related to the pharmacology
- unlikely to be fatal
Give examples of type A ADRs
- digoxin toxicity
- constipation with opioid analgesics
- bruising with warfarin
Give examples of type B ADR
Type B (bizarre) reactions are generally
- not dose related
- uncommon, unpredictable
- not related to the pharmacology
- often fatal
Name some examples of type B ADRs
- penicillin hypersensitivity
- malignant hyperthermia
- hepatitis caused by anaesthetic agents
describe type C ADRs and examples
- uncommon
- related to cumulative dose
- time related
examples
- suppression to the hypothalamic pituitary adrenal axis with long term corticosteroids
Describe type D ADRs and examples
Delayed
- uncommon
- usually dose related
- occurs or becomes apparent some time after use of drugs
Examples
- carcinogensis
Describe type E ADRs and examples
End of Treatment
- uncommon
- occurs soon after withdrawal of the drug
examples
- opiate withdrawal syndrome
Describe type F ADRs and examples
Failure
- common
- dose related
- often caused by drug interactions
Examples
- failure of the oral contraceptive in the presence of an enzyme inducer
- failure of therapeutic effect in patients taken anticoagulants leading to stroke
What is the new system used to look at ADR
DoTS
How does DoTS look at ADRs
- Dose
- Timing
- Susceptibility
What are the types of ADRs divided by dose (DoTS)
- Hyper-susceptibility reactions = occur at doses much lower that therapeutic
- Collateral effects - occur at therapeutic doses
- Toxic effect - occur at doses higher than those used therapeutically
How can ADRs be divided by time (DoTS)
- time dependent = those which are dependent on the time the patient has been taking the drugs
- Time independent = those which can occur at any time during the drug treatment
What are the things that make you susceptible to ADRs (DoTS)
- immunological reactions
- genetics
- age
- sex
- physiology
- exogenous
- disease states affecting the patient e.g. renal dysfunction, liver disease
IGASPED
Are harmful drug interactions adverse drug reactions
True