PHARMACODYNAMICS 4

Question 1

Physiologic antagonist occurs when drugs act independently at different receptors. Examples of this are:

Answer 1

Histamine + Epinephrine
Histamine + Salbutamol
Glucocorticoid + Insulin

Question 2

Also known as true antagonist because no receptor is involved

Answer 2

Chemical antagonist

Question 3

Examples of Chemical agonist

Answer 3

Paracetamol + N-Acetylcysteine
Warfarin + Vitamin K

Question 4

(T/F) Competitive antagonism is irreversible, and Non-Competitive antagonism is reversable

Answer 4

False (Competitive ago = reversable)

Question 5

(T/F) Competitive antagonist competes in same site, non-competitive binds to allosteric binding site.

Answer 5

True

Question 6

Examples drugs for non-compe antagonism

Answer 6

Phenoxybenzamine
DNA alkylating agent

Question 7

Refers to the regulation of an enzyme or other protein by binding an effector molecule at proteins allosteric site

Answer 7

Allosteric Modulation

Question 8

Type of allosteric modulation that occurs when binding one ligand enhances the attraction between substrate. AKA Allosteric activation

Answer 8

Positive allosteric modulation (ex. Hemoglobin + oxygen) 4 oxygen each

Question 9

Type of allosteric modulation that occurs when binding decreases the affinity for substrates. AKA allosteric inhibition

Answer 9

Negative Allosteric Modulation

Question 10

Example of Negative Allosteric Modulation

Answer 10

Strychnine block Glycine receptors

Question 11

Caused by continuous prolonged exposure of receptors to drugs leading to desensitization

Answer 11

Down regulation

Question 12

Caused by prolonged/continuous use of receptor blockers that causes denervation

Answer 12

Sensitization / Up-regualtion

Question 13

Caused by long term exposure then sudden cessation of drug use that causes upregulation

Answer 13

Hyperactivity/Supersensitivity

Question 14

Theory by langley from 1905 known as “Fit into a receptor”

Answer 14

Lock and Key theory

Question 15

Theory that states that it alters the conformation of its binding site / causes change in the shape.

Answer 15

Induced fit theory

Question 16

Theory that states that drug effect is directly proportional to the number of receptors occupied. it describes the behavior of agonist and antagonist “greater no. greater effect”

Answer 16

Occupancy theory

Question 17

Maximal drug is response is not equal to the maximal tissue response. (existence of partial agonist drugs)

Answer 17

Ariens theory 1954

Question 18

Theory added the concept of stimulus and efficacy

Answer 18

Stephenson’s theory 1956

Question 19

theory that describes relationship between dose and response “behaviour of full agonist”

Answer 19

Clark’s theory 1934

Question 20

Also known as paton theory “collision between drug and receptor”

Answer 20

Rate Theory