Adverse Drug Reactions Flashcards
Define: Adverse Drug Reactions
A response to a drug which is noxious and unintended, and which occurs at doses normally use in man for prophylaxis, diagnosis or therapy of disease
What are the 4 classes of ADRs?
Augmented (Type A)
Bizarre (Type B)
Explain: Type A reactions
Augmented Reactions
- caused by an excess of the drugs wanted pharmacological effect
- Usually when drug has a narrow therapeutic index
- Dose related ADRs usually caused altered pharmacokinetics
- mortality is low, morbidity is high
Examples of Type A ADRs?
Laxatives - diarrhoea Opiate analgesics - constipations Diuretics - incontinence Potassium supplement - hyperkalaemia Insulin - hypoglycaemia
Why do Type A ADRs affect children/elderly and renal/hepatic disease patients more?
multiple factors, but because of the different pharmacokinetics (drugs absorption/excretion)
Explain: Type B reactions?
Bizarre reaction
relatively rare, and not dose related (e.g. allergy, idiosyncratic reactions, genetically determined effects, not predictable)
Allergic reactions (hypersensitivity) do not resemble pharmacological actions reactions occurs on re-exposure to even small amount of drug
Severe reaction includes: anaphylaxis
Example of Type B reactions?
- Carbimazole - Agranulocytosis
- Paroxetine - Hepatitis
- Statins - myostis, myalgia, myopathy, rhabdo
- ACE inhibitors - Angioedema
- Penicillin - Rash
- SJS Syndrome
Example of Type C reaction?
Chronic or long-term effects
- osteoporosis with steroids and PPIs
- Thyroid dysfunction with amiodarone
Example of Type D reaction?
Delayed
- delayed skin reactions in the week following the procedure not uncommon
- flu-like illness can develop
Explain: Type E Reaction
End of dose
- withdrawal effects after long-term treatment
- rebound responses
Example of Type E reaction?
e.g. Beta Blockers, nasal sprays, PPIs
Example of Pharmacodynamic ADR
Asthmatic pt
- needs B agonist to relax airways
- if given a b blocker, may suffer severe asthma attack.
Parkinsons Pt
- needs something for N&V
- given metaclopramide, suffered worse extra-pyramidal s/e because metoclopramide affects dopamine receptors in the brain
What/where are the classification of ADR in the BNF
page 12-15 - ADRs
- Very common =>1 in 10
- Common = 1 in 100 to 1 in 10
- Uncommon = 1 in 1000 to 1 in 100
- Rare = 1 in 10000 to 1 in 1000
- Very rare = less than 10000`
What is a Serious Reaction?
Fatal Life threatening Disabling or incapacitating Result in prolonged hospitalisation Congenital abnormalities OR Medically significant - may not be life threatening but for pt it is extreme, e.g. headache
CHECK YELLOW CARD AT BACK OF BNF
What ADR can be caused by: NSAIDs
Dyspepsia
What adverse effects do Antipsychotics cause?
Extra-pyramidal (motor control and co-ordination)
WHat ADR do Iron Preps cause?
Nausea & Vomiting
What ADRs do ABx cause?
Rash/Allergy
What ADRs do Calcium Channel Blockers cause?
Oedema
What ADRs do opiate analgesics cause?
Constipation
What ADRs do diuretics cause?
Hypokalaemia
What ADRs do ACEi cause?
Cough
What ADRs do Cephlasporins cause?
Pseudomembranous colitis
Which groups are at high risk of ADRs?
- very young and >70
- females > men
- End stage organ failure (renal/hepatic)
- polypharmacy
- multiple disease states
