Exam 1 Definitions

Question 1

Ka

Answer 1

affinity –> measures the effectiveness with which a drug binds to a receptor

Question 2

absorption

Answer 2

rate at which the drug leaves its site of administration and the extent to which this occurs

Question 3

F

Answer 3

bioavliability –> the fraction of the unchanged drug reaching the systemic circulation

Question 4

distribution

Answer 4

movement of drugs from blood to the site of action

Question 5

Vd

Answer 5

volume of distribution –> a theoretical index of drug distribution between plasma and tissues

Question 6

Vc

Answer 6

volume of distribution at time zero

Question 7

Varea

Answer 7

volume of distribution under pseudo-equlibrium

Question 8

Vss

Answer 8

volume of distribution at a steady state

Question 9

metabolism

Answer 9

biotransformation of a drug to inactivate metabolites or active compounds

Question 10

excretion

Answer 10

irreversible elimination of the drug from the body

Question 11

clearance

Answer 11

volume of blood from which all drug appears to be removed in a given time

Question 12

t1/2

Answer 12

half life –> time for 50% disappearance of a drug

Question 13

Kd

Answer 13

affinity –> the drug concentration at which 50% of the receptors are bound

Question 14

EC50

Answer 14

potency –> represents the agonist concentration at which 50% of the maximal response is achieved

Question 15

Emax

Answer 15

represents the agonist concentration at which the maximal response is achieved

Question 16

competitive antagonist

Answer 16

shifts the dose response curve to the right (increases the EC50), same Emax; can be outcompeted by the agonist at high enough concentrations

Question 17

noncompetitive antagonist

Answer 17

lowers the Emax, same EC50

Question 18

action of a drug

Answer 18

initial consequence of the drug-target interaction

Question 19

drug effect

Answer 19

biochemical and physiological changes that occur as a consequence of drug action

Question 20

selectivity

Answer 20

the ability of a drug to affect a particular target in preference to others; often concentration dependent

Question 21

specificity

Answer 21

the capacity of a drug to cause a single action on a target

Question 22

therapeutic window

Answer 22

the concentration range over which a drug produces its therapeutic effect

Question 23

pharmacophore

Answer 23

abstract description of features needed for receptor-ligand interactions

Question 24

agonist

Answer 24

a drug that binds to and activates a receptor

Question 25

full agonist

Answer 25

creates the maximal response while occupying a relatively low number of receptors

Question 26

partial agonist

Answer 26

sub-maximal effect when occupying all of the receptors in the population

Question 27

antagonist

Answer 27

a drug that inhibits or prevents receptor-mediated agonist effects; can be competitive or noncompetitive

Question 28

inverse agonist

Answer 28

produces an effect opposite the agonist while binding to the same receptor as the agonist

Question 29

fractional occupancy

Answer 29

what dose you should aim for to occupy a certain number of receptors to achieve a certain response

Question 30

efficacy

Answer 30

maximal response of the drug; the degree to which different agonists produce varying responses, even when occupying the same proportion of receptors

Question 31

k

Answer 31

constant of proportionality

Question 32

E

Answer 32

extraction ratio --> the fraction of the concentration of blood going to an organ that is eliminated by some mechanism

Question 33

total body clearance

Answer 33

the sum of all the clearances of a drug in each organ

Question 34

P

Answer 34

permeability coefficient --> characterizes the physical interaction of the drug with the barrier

Question 35

partition coefficient

Answer 35

characterizes the equilibrium state to which the system will eventually evolve to, in which the net flux across the barrier is zero