Pharmacodynamics cont. Flashcards
What is a competitive antagonist?
Agonist and antagonist compete for the same binding site
What happens to the EC50 when a competitive antagonist is introduced?
Shifts to the right
Is the maximal effect still achieved with a competitive antagonist?
Yes
What happens to the maximal effect when a noncompetitive antagonist is introduced?
Decrease in maximal effect
What is the effect on the EC50 of a noncompetitive antagonist?
Stays relatively constant
What is a partial agonist?
Drug that produced a lower maximal response, as compared to the agonist
What are the EC50 and the Bmax for a partial agonist, relative to the full agonist?
Lower Bmax
EC50 shifts right
If a partial agonist has an EC50»_space;» full agonist, what effect will predominate?
partial agonist response
True or false: a single drug can be both an agonist, and an antagonist
True–depends on the tissue it is found in.
When deciding which drug is the most potent, what should you look at: the EC50, or the Bmax?
EC50
When deciding which drug is the most efficacious, what should you look at: the EC50, or the Bmax?
Bmax
What is the ED50?
Median effective dose–dose at which 50% of individuals exhibit a specific quantal effect
What is the TD50?
Median toxic dose–dose at which a specific toxic effect occurs 50% of the individuals tested
What is the LD50?
Dose that is lethal for 50% of individuals tested
What is the therapeutic index?
TD50/ED50
