Drug Action Flashcards
What are the main modes of action of drugs
Activation or blocking of Receptors
Activation or blocking of Enzyme Function
Opening or blocking of Ion Channels
Facilitation of blocking Transport Systems
What may a receptor be coupled with
Ion channels
G-proteins
Enzymes
Gene transcripts
What is affinity
The tightness of the drug binding to the receptor
What is occupancy
How much time the drug spends on the receptor
What is efficiency
How effective the drug is at producing a response from the receptor
What are agonists
Bind to a receptor causing an effect
What are partial agonists
More difficult to produce the drug/receptor effect than with an agonist - only have partial efficiency
Increased concentration will improve efficiency for some
What are the different types of antagonists
Reversible
Irreversible
What are reversible antagonists
Antagonistic effect reduced by increasing the concentration of the agonist
Give an example of a reversible antagonist
Atenolol (beta blocker)
What is an irreversible antagonist
Binds and reduces the available receptors for the agonist
Give an example of an irreversible antagonist
Phenoxybenzamine (alpha blocker)
How can drugs change enzyme action
Substrate antagonism - competitive
Non-competitive substrate inhibition
Can be reversible enzyme modification or irreversible modification
What can ion channel effects change
Cell electrical activity
Ion influx
