How do you define drug Efficacy?
it is the strength of a single drug-receptor interaction that evokes a response
What are Agonists and what do they cause?
drugs that bind to receptors and produce some effect similar to the response produced by endogenous agents, they possess intrinsic activity
What are Antagonists and what do they cause?
drugs that bind to receptors but DO NOT produce an effect, they possess no intrinsic activity.
What 2 things affect drug-receptor interactions?
Binding forces Structure Activity Relationships
What are the differences between Graded vs. Quantal Dose-Response Curves?
Quantal - based on all or none response, provides estimate of percent of subjects who will respond to any given dose
Graded - based on data from single subjects, provides info about potency and efficacy
What does a quantal dose response curve look like?
What does a graded dose response curve look like?
X is more potent, lower [x] needed to get EC50
X has a higher efficacy than Y
What are 4 key features of Competative Antagonists?
Reversible binding to receptor
Blockade can be overcome by increasing [agonist]
maximal response of agonist is not decreased
agonist dose-response curve in presence of competative antagonist is displaced to the right and parallel
What are features of Irreversible Competative Antagonists?
Typically covalently bound
Maximal response is deminished
Cannot overcome antagonist w/ increased agonist concentration
What are features of Partial Antagonists?
decrease the maximal response
Features of Non-competitive Antagonism?
antagonist does not bind to active site
What is an Inverse Agonist?
Binds to receptor site like an Agonist but has the opposite effect of the normal Agonist
Understand levels of response for Full agonists, partial agonists, inverse agonists and antagonists.
What are two types of changes in receptor sensitivity that can occur?
Desensitization - deminished response, altered binding of drug to receptor, lack or receptors, decreased coupling of drug-receptor complex & signaling
Supersentitization - increased response, can be drug induced or pathophysiological.