Drug action Flashcards
What are the 4 main modes of action
Activation or blocking of Receptors
Activating or blocking Enzyme function
Opening or blocking Ion Channels
Facilitation or blocking Transport systems
What do drugs bind and release from constantly
receptors
When is a receptor activated
When a drug is bound
What determines the effect of a drug response
The drug receptor interaction:
-Affinity
-Occupancy
The Drug induced response:
-Efficacy
What is meant by the affinity of a drug
the tightness of the drug binding to the receptor
What is meant by the occupancy of a drug
how much time the drug spends on the receptor
What is meant by the efficacy of a drug
how effective the drug is at producing a response from the receptor
What is meant by a agonist
Binds to a recptor and causes an effect
What is meant by partial agonists
More difficult to produce the drug/receptor effect than with an agonist
Increase partial agonist concentration will improve efficacy for some but not for others
What is meant by antagonists
A chemical substance that binds to and blocks the activation of certain receptors on cells, preventing a biological response
What types of antagonists do you get
Reversible and Irreversible
What is a reversible antagonist
Antagonist effect reduced by increasing the concentration of the agonist
What is a irreversible antagonist
Binds and reduces available receptors for the agonist
How can a drug change enzyme action
By either:
Substrate antagonism – competitive
Non-competitive substrate inhibition
What can drugs do to enzymes
Reversible enzyme modification
Irreversible modification
