Pharmacodynamics 1 (ppt 7)

Question 1

Molecular response

Answer 1

Enzyme activity/movement of ion across plasma membrane

Question 2

Cellular response

Answer 2

Secretion of hormones or neurotransmitters or modulation of cell motility

Question 3

Organ response

Answer 3

I.e. smooth m. contraction (ach)

Question 4

Whole animal response

Answer 4

• Behavior changes/response
• Can be lethal

Question 5

Therapeutic index

Answer 5

• TI=TD50/ED50
• ex: warfarin (small TI) and penicillin (larger TI)

Question 6

Efficacy vs potency

Answer 6

• efficacy= maximal effect
• potency= strength of dose (ADME factors; drug’s affinity for receptors)

Question 7

Potency

Answer 7

• EC50 measures it
• x axis

Question 8

Full agonist

Answer 8

• intrinsic activity= 1
• ex: isoprenaline mimics beta-adrenoreceptors

Question 9

Partial agonist

Answer 9

• partial response
• intrinsic activity <1

-ex: buprenorphine is partial opioid agonist

Question 10

Antagonist

Answer 10

• aka “blockers”
• inhibit agonist action
• ex: ranitidine is H2 agonist
• IA=0

Question 11

Inverse agonist

Answer 11

• produce opposite response to agonist
• intrinsic activity= 0 to -1

Question 12

Agonist-antagonist

Answer 12

• simultaneously agonist on one set and antagonist on another set
• ex: nalorphine (opioid) activates k-opioid receptor & blocks mu-opioid receptor

Question 13

What determines the degree of constitutive activity in the absence of drugs

Answer 13

Equilibrium between Ri (inactive r receptor) and Ra (active r receptor)

Question 14

Affinity of full agonist drugs for Ra compared to Ri

Answer 14

• stronger

-b maximal effect prod. @ sufficiently high drug concentration

Question 15

Neutral antagonist

Answer 15

• Dant
• equal affinity to both receptor conformations
• prevents binding of agonist

Question 16

Inverse agonist

Answer 16

• Di
• higher affinity for Ri receptor conformation
• prevents conversion to Ra state
• reduces constitutive activity

Question 17

Chemical antagonism

Answer 17

Ex: antacids

Question 18

Functional antagonism

Answer 18

• physiological antagonism
• ex: effects of insulin & glucagon on blood sugar

Question 19

Dispositional antagonism

Answer 19

• pharmacokinetic antagonism

Question 20

Receptor antagonism

Answer 20

• pharmacological antagonism
• competitive and non-competitive antagonisms

Question 21

Receptor binding competitive vs. noncompetitive

Answer 21

• competitive: reversible (van der waals or H2 bonds)
• non competitive: irreversible due to covalent bonds

Question 22

Competitive vs. noncompetitive antagonism receptor binding sites

Answer 22

• competitive: antagonist binds same receptor site as agonist
• non-competitive: antagonist binds w/ same receptor site as agonist or to allosteric site

Question 23

Efficacy for competitive vs. non-competitive antagonists

Answer 23

• competitive: remains same
• non competitive: decreases

Question 24

Slope for competitive vs. non-competitive antagonists

Answer 24

• competitive: remains same
• non-competitive: decreases

Question 25

Position of competitive vs. non-competitive antagonists on interaction dose response curves

Answer 25

• competitive: shifts right
• non-competitive: remains same

Question 26

Intensity of response competitive vs. non-competitive antagonists

Answer 26

• competitive: depends on agonist and antagonist conc.
• non-competitive: depends on antagonist conc.

Question 27

Antagonism comparison between competitive and non-competitive antagonism

Answer 27

• competitive: surmountable
• non-competitive: unsurmountable

Question 28

Duration of actions for competitive vs. non-competitive antagonists

Answer 28

• competitive: short, depends on drug clearance
• non-competitive: long, depends on new receptor synthesis

Question 29

Examples of competitive and non-competitive antagonists

Answer 29

• competitive: morphine-naloxone
• non-competitive: diazepam-bicuculline