5.4: Adverse Drug Reactions Flashcards
What is an adverse drug reaction?
Any undesirable reaction (whether expected/predictable or not) that results in the detriment to the wellbeing of the patient in anyway
True or False:
- An adverse drug reaction is the same as a side effect?
FALSE
An adverse drug reaction is not the same as a side effect
What are the types of adverse drug reactions?
Type A = Augmented Pharmacological Effects
Type B = Bizarre Effects
Type C = Chronic Effects
Type D = Delayed Effects
Type E = End of treatment Effects
Type F: Failure of Therapy
Describe Type A drug reaction?
Augmented Pharmacological Effects
- Dose dependent
- Predictable
We know this is going to happen
Who are adverse drug reactions most common in?
Elderly
Multimorbidity (Renal/Hepatic Clearance affected)
Polypharmacy
What is the therapeutic index?
Tells us how risky a drug is
50% of a lethal dose/50% of the effective dose
Low therapeutic index - be very cautious
High therapeutic index - be less cautious
TI = LD50
ED50
Name some drugs with a narrow therapeutic index?
What should be done when giving these drugs?
Warfarin
Digoxin
Gentamicin
Vanomycin
Lithium
Close monitoring and caution
Describe the stages of ADR detection?
- Drug Development Stage (Pre-clinical)
- Most effiicent, least morbidity, least cost - Clinical Trials
- Often not picked up due to small sample size - Post-Marketing Surveillance
- This is when most data is available, higher risk of morbidity and mortality, highest cost
Where are most ADRs picked up?
In the post-marketing surviellance (once the drug has been licensed and distributed to the general poupulation)
What are the two phases of drug metabolism?
Where do ADRs occur (Which phase?)
Phase 1 = Cyp P450 (Oxidation, Reduction and/or Hydrolysis -BREAK THE DRUG DOWN)
Phase 2 = Conjugation (Water soluble) - ALLOWS DRUG TO BE SECRETED
Most ADRs occur in phase 1
Give some examples of pre-renal, post-renal and intra-renal drug reactions?
FOR TYPE ‘A’ DRUG FAILURE
Pre-Renal
- Diuretics causing hypovolaemia
- ACEIs and ARBs causing diarrhoea and vomiting
Renal
- Gentamicin causing sepsis
Post-Renal
- Chemotherapy causes renal stones
Describe ACE Inhibitiors/ARBs in diarrhoea and vomiting?
Patients should not take ACE Inhibitors or ARBS if they are very dehydrated
This causes decreased kidney function and renal failure
In type A drug reactions:
- You know/do not know what is going to happen to the patient?
- You should/should not make changes to accomodate this interaction?
In type A drug reactions
You know what is going to happen to the patient
You should make changes to accomodate this interaction
Name the three types of Type A Interactions?
Drug-Drug Interactions
Drug-Disease Interactions
- Drug-Food Interactions
75% of all adverse drug reactions are…?
(Which type?)
Type A
