Pharmacodynamics

Question 1

What do drugs do?

Answer 1

• alter the rate of bodily functions

- modulate intrinsic physiological functions

Question 2

Law of Mass Action

Answer 2

-rate of association of a molecule to a surface is equal to the rate of dissociation of the molecule from the surface

Question 3

Adsorption isotherm depends on the interaction of which 2 molecules?

Answer 3

ligand and receptor

Question 4

Receptor occupation theory

Answer 4

a bimolecular interaction where a drug binds reversibly to the receptor so equilibrium is reached

Question 5

Orthosteric agonist

Answer 5

a drug agonist activating the same receptor site as that acted upon by a physiological agonist

Question 6

What happens to a dose-response curve when transferred to a logarithmic plot?

Answer 6

sigmoidal

Question 7

How do you find potency of drug using a dose response curve?

Answer 7

50% response across and then down to the dose concentration

Question 8

What is the intrinsic activity of a drug?

Answer 8

the ability of a ligand to activate a receptor and the signal transduction system linked to that receptor

Question 9

What is the equation for intrinsic activity and how can you interpret the results?

Answer 9

Emax of an agonist/Emax of full agonist
alpha=1 – full agonist
alpha >0,<1 – partial agonist
alpha=0 – antagonist

Question 10

Why would an agonist be classified as a partial agonist?

Answer 10

• slow on/off receptor kinetics

- partial receptor activation

Question 11

What are spare receptors?

Answer 11

The percentage of receptors that are left over after reaching maximal efficacy

Question 12

Which has more of an effect on signal transduction activation: affinity for receptor or intrinsic activity?

Answer 12

affinity

Question 13

The potency of a drug is dependent on what?

Answer 13

• affinity (binding of the receptor)

- efficacy (response elicited by drug-bound receptor)

Question 14

What are common allosteric antagonists?

Answer 14

activating antibodies (IgG)

Question 15

Allosteric antagonists have uniformly ______ intrinsic activity.

Answer 15

less

Question 16

What is an allosteric antagonist’s potency compared to agonists?

Answer 16

can be more or less potent

Question 17

Clinical dose range

Answer 17

20-80% of dosage curve

Question 18

All competitive antaganists are __________

Answer 18

orthosteric

Question 19

Antagonists are generally ______ lipid soluble, higher relative ________, and _______ molecular weight

Answer 19

more; affinity (for receptor); larger

Question 20

what is DR10?

Answer 20

dose required to increase ED50 by 10-fold

Question 21

What are the 2 forms of non-competitive agonists?

Answer 21

orthosteric irreversible antagonism: “suicide molecule”

allosteric antagonism: conformational change that does not allow binding of ligand (hormone or drug)

Question 22

“Suicide molecules” are _______-dependent

Answer 22

concentration

Question 23

What kind of drug has pharmacological effects than far outlast their duration in the plasma?

Answer 23

“suicide” molecules/orthosteric irreversible antagonism

Question 24

How can the body reactivate its receptor after an orthosteric irreversible antagonist/”suicide” molecule binds?

Answer 24

using lysosomal degradation of the covalently bound receptor and synthesize new receptors

Question 25

How do you calculate therapeutic index?

Answer 25

LD50/ED50

Question 26

How do you calculate margin of safety?

Answer 26

LD01/ED99

Question 27

What is a constitutively active receptor?

Answer 27

receptor has a basal activity level that can be increased in presence of agonist, but not needed

Question 28

What is an inverse agonist?

Answer 28

binds to constitutively active receptor causing an uncoupling and decrease in signal transduction in a dose-dependent manner

Question 29

What are the types of bias in signal transduction pathways?

Answer 29

• balanced signaling bias
• Agonist (ligand) bias
• Receptor bias
• Tissue bias