What is EC50?
The EC50 is the concentratin of the agonist that causes 50% of the maximum response
What is afinity?
The affinity is the tendency of the drug to bind to its receptor
What is efficacy?
The efficacy is the tendency for the drug (once bound) to activate its receptor.
What is the Therapeutic Index?
Therapeutic dose ED 50% (experimental dose)
What does a HIGH therapeutic index mean?
That the drug has a wide safety margin e.g penicillin
What is an agonist?
An agonist is a substance/drug that binds to recpetors and produces a response.
What is an antagaonist?
An antagonist binds to a receptor, therefore preventing the agonist from binding, but it does not cause a response.
Does an agonist have affinity and efficacy?
What about antagonists?
AGONIST..... affinity AND efficacy
ANTAGONIST... affinity but NO efficacy
What does a competitive agonist do?
It occupies the recpetors so that more agonist is needed to produce any given response.
Causes the log concentration/response curve for the agonist to be shifted to the right.
What is potency?
The potency of the agonist refers to the concentration casuing a particular magnitude of response. It is measured using the EC
= less potent
= more potent
What is a partial agonist?
A partial agonist is an agonist that fails to produce a maximum response even when it occupies 100% of the receptors.
Pharmacology terms revision