Harmful Effects of Drugs Flashcards
(40 cards)
What is the definition of an adverse reaction?
Harmful or seriously unpleasant effects at doses intended for therapeutic use and which call for a reduction in dose and/or withdrawal of drug.
(Lecture 12, Slide 4)
What is a therapeutic window?
The time range between injury and treatment in which the drug is still effective.
(Lecture 12, Slide 6)
What is the LD50 (Lethal Dose, 50%)?
The dose required to kill half the members of a tested population.
(Lecture 12, Slide 7)
What is LD50 used for?
To generally indicate a substance’s acute toxicity.
(Lecture 12, Slide 7)
What is LD50 usually expressed as?
The mass of substance administered per unit mass of test subject, e.g 5mg/kg
(Lecture 12, Slide 7)
How can Atropine cause blurred vision?
It binds to all muscarinic cholinoceptors (mACh) as a competitive antagonist, but many of these are present in the eyes, resulting in pupils dilating and causing blurred vision
(Lecture 12, Slide 12)
How can Aspirin cause gastric bleeding?
Blocks cyclooxygenase (COX) enzymes present at sites of inflammation, but these are also present in the wall of the gut, causing gastric bleeding
(Lecture 12, Slide 15)
How can Levodopa cause psychoses (losing touch with reality)?
It replaces dopamine lost in Parkinson’s disease, but excess dopamine can cause psychosis
(Lecture 12, Slide 17)
What is the definition of a side effect?
An unintended effect that can be predicted from known action of the drug
(Lecture 12, Slide 18)
What is an idiosyncratic reaction?
A genetically determined, abnormal response to a drug that cannot be predicted
(Lecture 12, Slide 21)
What is organ specific toxicity?
A side effect which is specific to a tissue or organ within the body
(Lecture 12, Slide 37)
How can chloroquine cause eye damage?
Accumulation of the drug may result in deposits that can lead to blurred vision and blindness.
(Lecture 12, Slide 43)
What correlation does drug allergy/hypersensitivity have with known actions of the drug?
None.
(Lecture 13, Slide 5)
What are 2 things drug allergy/hypersensitivity consist of?
One or more of the following;
Rash
Skin / mucous membrane swelling
Serum sickness syndrome
Asthma
Anaphylaxis
(Lecture 13, Slide 5)
What is type 1 hypersensitivity?
An allergic reaction, local or systemic provoked by re-exposure to a specific antigen
(Lecture 13, Slide 8)
What is the first step of type 1 hypersensitivity occuring?
Drug induces production of IgE immunoglobulin antibodies which then attach to mast cells.
(Lecture 13, Slide 8)
What happens after IgE immunoglobulin antibodies attach to mast cells in type 1 hypersensitivity reactions?
When drug (antigen) is re-administered, it binds to the IgE antibodies on the surface of the mast cells
(Lecture 13, Slide 8)
What does the drug (antigen) attaching to the IgE antibodies in type 1 sensitivity induce and what does this result in?
Mast cell degranulation resulting in the release of chemical mediators, such as histamine
(Lecture 13, Slide 8)
How long do type 1 hypersensitivity reactions take?
Immediate, within seconds to minutes
(Lecture 13, Slide 8)
What is anaphylaxis?
Circulatory collapse with a massive fall in blood pressure
(Lecture 13, Slide 11)
What are 3 examples of type 1 hypersensitivity?
Allergic asthma
Allergic conjunctivitis
Allergic rhinitis (“hay fever”)
Angioedema (swelling of deeper layers of the skin)
Atopic dermatitis (eczema)
Urticaria (hives)
(Lecture 13, Slide 12)
What occurs first in type 2 hypersensitivity?
Drug associates with a protein on the cells which forms a complex which acts as an antigen.
(Lecture 13, Slide 15)
What occurs after the drug forms a complex with a protein in type 2 sensitivity?
Leads to production of antibodies IgG and IgM
(Lecture 13, Slide 15)
What happens after IgG and IgM are produced in type 2 sensitivity?
Antibody and drug-protein antigen can combine to activate complex, which destroys cells
(Lecture 13, Slide 15)
