Adverse Drug Reaction Flashcards
What is a Contraindication?
A specific Situation in which a drug should NOT be used because it may be ahrmful to a person
What is Special Precaution?
A condition that may increase the risk of an adverse reaction. eg. Paracetemol overdose causing Liver Failure
What is an Adverse Drug reaction?
ADR is an unwanted/unintended and undesirable effect of a drug at doses NORMALLY USED FOR THERAPY
What is an Adverse Drug Event?
Untoward Medical Occurence of a drug which DOES NOT NECCESARILY have a causal relationship with the treatment
What are the 2 types of ADR?
Type A (Augmented) and Type B (Bizzare)
What are the characteristics of Type A ADR?
1) Common
2) Pharmacologically predictable
3) Low Mortality
4) Dose dependent
What are examples of Type A ADR?
Anti-Hypertensive Drugs - Hypotension
Blood thinner - Bleeding
Anti-histamines - Drowsiness
COX-2 Selective inhibitors - thromboembolism
What are the characteristics of Type B (Bizarre) ADR?
1) Uncommon
2) Pharmacologically unpredictable
3) High mortality
4) Dose Independent
5) Idiosyncratic (Not due to immune system)
6) Hypersensitivity
What are examples of Type B ADR?
Antibiotics (Penicillin) - Anaphylaxis
What are the differences in Management of Type A and Type B ADR?
Type A - Dose Reduction
Type B - Stop
What are the 4 types of Immune Reactions from Type B ADR (Hypersensitivity)?
Type I (Ig-E mediated)
Type II (cytotoxic)
Type III (Immune Complex)
Type IV (delayed, Cell mediated)
What is the mechanism of Type I? and Clinical manifestation?
Drug Ig-E complex binding to mast cells cause release of Histamine
Angiodema, anaphylaxis
What is the mechanism of Type II? and Clinical manifestation?
IgG or IgM directed at drug hapten coated cells
Hemolytic Anemia, Thrombocytopenia
What is the mechanism of Type III? and Clinical manifestation?
Drug Antibody complex deposition with complement activation and inflammation
Fever, Rash …
What is the mechanism of Type IV? and Clinical manifestation?
Drug molecule presentation to T cells with cytokine and mediator release
Steven- Johnson Syndrome
What is the timing of reaction for each of the Immune Reaction?
Type I (IgE mediated) - Minutes to Hours
Type II (Cytotoxic) - 12-36 Hours
Type III (Immune Complex) - 1-2 Weeks
Type IV (delayed, cell mediated) - 2-3 Days
What are the Risk factors for Drug Hypersensitivity?
Larger molecules are most likely immunogenic
Small molecule drugs (hapten) can form simple chemical-carrier protein complexes becoming immunogenic
Route of administration can induce hypersensitivty
Topical»_space;IM, IV (more serious)»_space; oral
What are Idiosyncratic ADRs?
NOT exactly Drug hypersensitivity
ADR that resembles Type1 immediate hypersensitivity, but not mediated by IGE
Occur when mast cells are activated (via Mas-related GPCR X2)
Pseudoallergic/ Anaphylactoid
What are the other 3 types of ADR?
Type C (Chronic) - related to both dose and time
uncommon, cumulative dose and long term use
(eg. NSAIDs: Nephrotoxicity)
Type D (Delayed) - Time related
Uncommon, dose related, apparent some time after use of drug
(eg. Cytotoxic anti-cancer drugs, blooth thinner)
Type E (End of Dose) - Withdrawal Syndrome
What are the populations at Greatest risks of ADR?
Pediatrics, Geriatrics, Renal/Hepatic Impaired, Genetic Variations
