TEST 2 Dose-Response Relationship

Question 1

Define dose:

Answer 1

The amount of drug administered

Question 2

Define response?

Answer 2

A change in biological activity.

Question 3

Define Dose-response relationships?

Answer 3

The relationship between the amount of a drug administered and the observed change in a biological function.

Question 4

What are the two response theories?

Answer 4

Occupation and Rate Theory

Question 5

Describe Occupation Theory?

Answer 5

The magnitude of a response is proportional to the number of receptors occupied by a drug.

Question 6

Describe Rate theory?

Answer 6

The magnitude of a response is proportional to the rate of formation of the D-R complex.

Question 7

Define the Dissociation constant mathematically.

Answer 7

K_D=K₂/K₁

Question 8

Define Intrinsic Activity?

Answer 8

The ability of a drug to induce a biological response.

Question 9

Define Efficacy?

Answer 9

Maximal effect produced by a drug

Question 10

Define Potency?

Answer 10

Determined by the dose needed to produce a particular effect of given intensity

Question 11

Define Agonist?

Answer 11

A drug which possesses affinity and intrinsic activity.

Question 12

Define Partial Agonist?

Answer 12

An agonist with lower efficacy than a full agonist

Question 13

Define Antagonist?

Answer 13

A drug which possesses affinity but little or no intrinsic activity.

Question 14

Define Specificity?

Answer 14

Ability of a drug to exert its effect through a single mechanism of action

Question 15

Define Selectivity?

Answer 15

Ability of a drug to induce one effect in preference to another effect.

Question 16

What type of graph does an Competitive antagonist create?

Answer 16

Logarithmic curve

Question 17

What effect does a competitive antagonist have on the agonist effect graph.

Answer 17

Moves the curve to the left.

Question 18

What type of graph does an Non-competitive antagonist create?

Answer 18

Logarithmic curves

Question 19

What effect does a competitive antagonist have on the agonist effect graph?

Answer 19

Lowers peak % maximal effect

Question 20

What effect on the agonist do different antagonists have on a double reciprocal plot.

Answer 20

• Non-competitive antagonist:
  
  • x-intercept doesn’t change
  • y-intercept moves up.
• Competitive antagonist
  
  • x-intercept moves right.
  • y-intercept doesn’t move.

Question 21

Define Median Effective Dose (ED₅₀)

Answer 21

Dose required to produce specific therapeutic effect in 50% of test subjects.

Question 22

Define Lethal Dose (LD₅₀)?

Answer 22

Dose required to produce death in 50% of test subjects.

Question 23

Define Median Toxic Dose (TD₅₀)?

Answer 23

Dose required to produce a toxic effect in 50% of test subjects.

Question 24

Define Therapeutic ratio or index?

Answer 24

The LD₅₀/ED₅₀ ratio for a drug. The larger the ratio, the safer the drug.

Question 25

Define Certain Safety Factor?

Answer 25

• The LD1/ED99 ratio for a drug.
  
  • If the ratio is:
    
    • <1, the two curves overlap
    • >1, little or no overlap.

Question 26

Define Standard safety margin?

Answer 26

(LD1-ED99)/ED99 X 100 =

Represents the percent that the ED99 must be increased to be lethal in 1% of the test subjects.

Question 27

What are the three decreased response relationships?

Answer 27

Tolerance, Tachyphylaxis, Resistance

Question 28

What are the three increased response relationships?

Answer 28

Additive effects, synergism, potentiation.

Question 29

Define Tolerance:

Answer 29

A decrease in efficacy with repeated drug administration.

Question 30

Define Tachyphylaxis

Answer 30

An acute form of tolerance due to rapid, repeated administration of a drug.

Question 31

Define Resistance:

Answer 31

A decreased or complete lack of responsiveness to drugs that normally inhibit or cause cell death.

Question 32

Define Additive effects:

Answer 32

The combination of two drugs induces an effect equal to the sum of the effects of the two drugs when administered individually.

Question 33

Define Synergism:

Answer 33

The combination of two drugs induces an effect which is greater than the sum of the effects of the two drugs when administered individually.

Question 34

Define Potentiation:

Answer 34

Administration of a drug with little or no efficacy enhances the biological shift to the left of the dose-response curve for the antagonist.