1: Introduction to drug action Flashcards
What is pharmacodynamics?
What the drug does to the body
What is pharmacokinetics?
What the body does to the drug
shifts it - kinetic
What is a drug?
Any substance used in the treatment, prevention or diagnosis of disease
For a drug to be useful as a therapeutic agent, it needs to act with a degree of ___.
selectivity
Drugs act by ___ to molecules.
binding
Name some proteins which drugs can bind to.
Enzymes
Carrier molecules
Channels
Receptors
Drugs also bind to which acids?
DNA / RNA
Under normal circumstances, which signal molecules bind to receptors?
Hormones
Neurotransmitters
What are the two main classes of drug?
Agonists
Antagonists
What is an agonist?
A molecule which binds to a receptor to produce a response
What is an antagonist?
A molecule which blocks the action of an agonist
Agonists bind to receptors which ___ them.
activates
Is binding to a receptor the same as activating it?
No
Activation usually occurs as a result of binding, but they’re two separate steps
What is affinity?
The strength of association between a ligand and a receptor
Drugs with ___ affinity will dissociate from their receptor quickly.
low
Drugs with ___ affinity will dissociate from their receptor slowly.
high
What is efficacy?
The ability of an agonist to produce a cellular response
___ efficacy produces a big cellular response.
High
___ efficacy produces a small cellular response.
Low
Do antagonists activate receptors?
What does this say about their efficacy?
No - only block them
Low efficacy
Antagonists have ___ but not ___.
(affinity / efficacy)
affinity , efficacy
Antagonists block receptor activation by ___.
agonists
As agonist concentration increases, receptor occupancy ___.
Does this happen indefinitely?
increases
No - eventually saturation of all available receptors occurs
What is EC50?
The concentration of agonist which produces a HALF MAXIMAL RESPONSE
