Dose-Response Relationships

Question 1

Dose-response relationships:

Answer 1

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

Question 2

Occupation theory:

Answer 2

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

Question 3

Rate theory:

Answer 3

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

Question 4

Kd

Answer 4

Dissociation constant.

Question 5

Efficacy:

Answer 5

Maximal effect produced by a drug.

Question 6

Potency:

Answer 6

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

Question 7

Specificity:

Answer 7

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

Question 8

Selectivity:

Answer 8

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

Question 9

Competitive antagonist curves:

Answer 9

Parallel shift to the right of logarithmic curve when competitive antagonist is added.

Question 10

Noncompetitive antagonist curves:

Answer 10

Smaller logarithmic curve when noncompetitive antagonist is added.

Question 11

ED50:

Answer 11

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

Question 12

LD50:

Answer 12

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

Question 13

TD50:

Answer 13

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

Question 14

Therapeutic ratio/index:

Answer 14

LD50/ED50

- The larger the ratio the safer the drug.

Question 15

Certain safety factor:

Answer 15

LD1/ED99 ratio for a drug.

• < 1 the two curves overlap.
• > 1 the two curves do not overlap.

Question 16

Standard safety margin:

Answer 16

(LD1 - ED99)/ED99 x 100

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

Question 17

Tachyphylaxis:

Answer 17

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

Question 18

Additive effects:

Answer 18

The combination of two drugs induces an effect equal to the sum of the effect of the two drugs.

Question 19

Synergism:

Answer 19

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

Question 20

Potentiation:

Answer 20

Administration of a drug with little or no efficacy enhances the biological response induced by an agonist.
- Parallel shift to the left of the dose-response curve for the agonist.