Pharmacodynamics Flashcards
What is pharmacodynamics?
What the drug does to the body
What are the main ways drugs exert their effects on the body?
Receptors
Enzymes
Ion channels
Transporter molecules
How do drugs tend to work?
Mimicking signals Blocking signals Replacing missing chemicals Stimulating particular cell activity Slowing or inhibiting activity
How do receptors work?
Cells have different types of receptors
Only substances which fit the shape can interact with the cell
Like a lock and key
What is efficacy?
The measure of the bound ligand that activates a response
What is affinity?
The interaction better a drug and a binding site
The closer the fit the greater number of bounds and the higher affinity of a drug for the receptor
Essentially it is the ability a drug has to bind to a receptor
What is specificity?
The ability of a drug to combine with one particular type of receptor
No drug has complete specificity
How do receptor drugs work?
By either stimulating or inhibiting activity of the cell
What is an agonist?
The drug has the same effect on the receptor as the natural substances that normally bind and it mimics the actions of normally binging ligands
What is an antagonist?
It prevents the actions of an agonist
Stops the actions of naturally occurring ligands
What is competing receptor antagonism?
It is when a antagonist binds to a receptor to prevent the agonist from binding
What is reversible competitive antagonism?
It competes with the agonist for binding site but can be overcome by the agonist
What is non-reversible competitive antagonism?
It competes with the agonist but due to strong bonds cannot be broken
What is non competitive antagonism?
It is when a drug binds to a site other than the agonist site and blocks the natural agonist
What do drugs acting on enzymes do?
They are similar size and shape to substrate and bind to the active site to inhibit enzyme action
Can be competitive and non-competitive
