Pharmacodynamics

Question 1

Receptor

Answer 1

Binds drugs, transduces binding into a response

Question 2

Ligands

Answer 2

Drugs, bind to receptors

Question 3

K_D

Answer 3

K_D = k₂/k₁ = [L] * [R]/[LR]

• Equilibrium, dissociation constant
• Describes the goodness of fit between ligand and receptor
• Inversely related to the affinity of ligand for the receptor
• Has units of concentration

Question 4

Affinity

Answer 4

The ability of the drug to bind to a receptor

Question 5

R_T

Answer 5

R_T = [LR] + [R]

Total number of receptors in a cell or tissue (bound and unbound)

Question 6

Intrinsic activity

Answer 6

(α), measure of the ability of the LR complex to elicit the effect being measured, also called efficacy

• Is the ratio of the Emax of the ligand of interest to the Emax of a full agonist
• Full agonist, α = 1
• Antagonist, α = 0

Question 7

Agonist

Answer 7

Drug with an intrinsic activity (α) of 1

Question 8

Antagonist

Answer 8

Drug with an intrinsic activity (α) of 0

Question 9

Partial agonist

Answer 9

Drug with an intrinsic activity (α) between 0 and 1

Question 10

Spare receptors

Answer 10

Increase the sensitivity of the cell to a low concentration of ligand

Allows for high sensitivity without long activation time

Question 11

Potency

Answer 11

The relationship between the amount of drug administered and its effect, determines the position of the curve on the x-axis

Determined by:

• Affinity for the site of action
• Ability to reach site of action

Question 12

Efficacy

Answer 12

Intrinsic activity, the relative ability of a drug-receptor complex to produce a maximum functional response

Determined by:

• Intrinsic activity
• Characteristics of the effector
• Limitations on the amount of drug that can be administered

Question 13

Maximum efficacy

Answer 13

Maximal effect that is produced by a drug, it is the maximum point on the y-axis that is reached

Question 14

ED50

Answer 14

the dose that produces the desired effect in half of the population

Question 15

Hypersensitivity

Answer 15

allergic or inflammatory response to a drug

Question 16

Hyperreactive

Answer 16

an unusually low dose of drug produces its expected pharmacologic effects

Question 17

Hyporeactive

Answer 17

require exceptionally large doses of drug to evoke expected pharmacologic effects

Question 18

Therapeutic index

Answer 18

Ratio of TD50/ED50

The ratio of the dose that produces a toxic effect in half of the population to the dose that produces the desired effect in half of the population

Question 19

TD50

Answer 19

Median toxic dose

the dose that produces a toxic effect in half of the population

Question 20

LD50

Answer 20

Median lethal dose

the dose that kills in half of the population

Question 21

Log-normal distribution

Answer 21

You know what it is.