Pharmacodynamics - Part 1

Question 1

What is the definition of pharmacodynamics?

Answer 1

The study of the impact of drugs on the body or drug actions.

Question 2

No drug produces a _______ effect.

Answer 2

single

Question 3

Drug actions occur because _______ binds to _______ ______.

Answer 3

drugs - cellular targets

Question 4

When drugs bind to cellular targets this:

• initiates ________ ________
• pharmacological effect is due to the alteration of an intrinsic physiological process and ___ the creation of a _____ process.

Answer 4

biochemical reactions

NOT - new process

Question 5

Every drug tends to have more than one ______, and thus more than one _____.

Answer 5

target

action

Question 6

In this class, the term cellular target can be used interchangeably with what?

Answer 6

receptor

Question 7

In drug action, we cannot create ____ ________.

We can either ______ the process or ________ it.

Answer 7

new processes

enhance or inhibit

Question 8

Drug action essentially alters what?

Answer 8

Intrinsic physiological processes

Question 9

Where are drug targets present?

Answer 9

Cell surface
Organelle within the cell
In the cytoplasm

Question 10

There is a _______ number of receptors in a given cell.

This means that _______-mediated responses _______ upon ________ of all receptors.

Answer 10

finite
receptor
plateau
saturation

Question 11

What are different drug targets?

Answer 11

Proteins/glycoproteins
Nucleic acids
Carbohydrates
Lipids

Question 12

What are the different protein/glycoprotein drug targets?

Answer 12

Enzymes

receptors

Question 13

What are the different nucleic acid drug targets?

Answer 13

DNA and RNA

Question 14

What are the different Carb drug targets?

Answer 14

Glcyogen

Cell surface receptors

Question 15

What is the lipid drug target?

Answer 15

Cell membranes

Question 16

Most receptors or drug tragets are of what kind?

Answer 16

Proteins/glycoproteins.

Question 17

Drug action occurs:
- when the concentration or quantity of the drug at the site of responsive tissue attains a certain _______ ________ level

Answer 17

critical minimal

Question 18

The certain critical minimal level which equates “effective” level can be determined by __ general factors?
What are they?

Answer 18

4

• affinity of the drug to the targets
• Ability of the drug to cause changes
• Responsiveness of the target to the changes
• adaptability of the target-tissues/organs to the changes

Question 19

The 4 general factors for determinign the effective level of drug concentration for drug action:

• ______ of the drug to the targets
• Ability of the drug to cause ______
• ____________ of the target to the changes
• ___________ of the target-tissues/organs to the changes

Answer 19

Affinity
changes
responsiveness
adaptability

Question 20

What is critical for drug action to occur?

Answer 20

Drug needs to be present near the receptor, and in sufficient quantity

Question 21

Describe a drug that would not cause a change.

Answer 21

Diagnostic compound that binds to receptor to track changes but doesnt cause any change.

Question 22

Describe adaptability to drug action.

Answer 22

Change occurs, but cell adapts to the change.

- body might produce more receptor

Question 23

Why is drug adaptability important for drug action?

Answer 23

If the cell adjusts too quickly, drug action may not occur

Question 24

The affinity of drug targets refers to:

- the ______ of binding between the drug and receptor

Answer 24

strength

Question 25

What does the affinity of drug targets mean?

Answer 25

The strength of binding between the drug and receptor

Question 26

The number of occupied receptors is a function of the balance between ______ and _______ drug

Answer 26

free and bound

Question 27

What are the different intermolcular interaction important for drug affinity to a target?

Answer 27

Ionic, H-bond, VdW, Covalent

Question 28

Describe not easily breakable covalent bonds.

Answer 28

Some drugs bind to targets irreversibly and remove the target from its natural action completely - ex: tamoxiffen cancer drug

Question 29

The majority of drug binding to targets is ________.

Answer 29

reversible

Question 30

For the majority of drugs, they _______ with natural compounds for the natural _______.

Answer 30

compete | target

Question 31

When a drug binds covalently and the bond is not easily breakable, this means?

Answer 31

The action is permanent

Question 32

Affinity is used to describe how ______ the interaction between the ______ and the _______ is.

Answer 32

strong ligand receptor

Question 33

What is the measure of drug affinity?

Answer 33

Dissociation constant - Kd

Question 34

kd is reciprocally related to what?

Answer 34

ka

Question 35

Using the standard A = B --> AB nomenclature, provide Kd and Ka.

Answer 35

``` ka = AB/A + B kd = A+B/AB ```

Question 36

The association constant can be thought of as the eqb constant in the ______ direciton; the dissociation constant can be thought of the eqb constant in the ______ direction.

Answer 36

forward | reverse

Question 37

At equilibrium, what is Kd equal to?

Answer 37

kd/ka = Kd

Question 38

Experimentally, related to Kd, a _______ ______ can be plotted.

Answer 38

binding curve

Question 39

What are the axes of the binding curve?

Answer 39

Y - fraction B bound | X - Concentration of A free

Question 40

How can one determine Kd from a binding curve?

Answer 40

When 50% of B (receptor) is bound by A (ligand), the binding curve value is equal to Kd.

Question 41

A translation to the right of the binding curve means what? | Left translation?

Answer 41

Right - binds worse, less affinity | Left - more affinity

Question 42

What is an issue with the binding curve?

Answer 42

Hard to determine the 50% mark by eye-balling

Question 43

What is the linear plot equivalent of a binding curve?

Answer 43

Scatchard plot

Question 44

What are the different parts of a scatchard plot?

Answer 44

Y - [fraction bound B/A] X - [Fraction bound B] y-intercept = 1/Kd slope = -1/Kd

Question 45

Define the dissociation constant.

Answer 45

Measure of a drug's affinity for a given receptor | Defined as the concentration of a drug required in solution to achieve 50% occupancy of its receptors.

Question 46

A higher affinity shows ______ concentration of drug required in solution to achieve 50% occupancy of its receptors.

Answer 46

less

Question 47

Define efficacy.

Answer 47

Degree to which a drug is able to produce the desired response.

Question 48

Define potency

Answer 48

Amount of drug required to produce 50% of the maximal response the drug is capable of inducing

Question 49

What is potency used for?

Answer 49

Compare compounds within the SAME class of drugs

Question 50

What is effective concentration 50% (ED50)?

Answer 50

Concentration of the drug which induces a specified clinical effect in 50% of subjects

Question 51

What is the Lethal dose 50% (LD50)?

Answer 51

concentration of the drug which induces death in 50% of subjects

Question 52

What is the therapeutic index?

Answer 52

Measure of the safety of a drug. - provides the margin of safety Margin between the therapeutic and lethal doses of a drug

Question 53

How is the therapeutic index calculated?

Answer 53

LD50/ED50