4: Pharmacodynamics

Question 1

Pharmacokinetics vs pharmacodynamics

Answer 1

Kinetics: effects of body on drugs
Dynamics: effects of drug on body

Question 2

Emax vs ED50

Answer 2

Emax: max effect that can be produced by a drug
ED50: dose of drug that produces 50% of max effect

Question 3

What does the graded dose response curve represent?

Answer 3

Mean value within a population or a single subject

Question 4

What does a quantal dose response curve show

Answer 4

Does the response occur or not, and in how many people? Is a yes/no binary response

Question 5

Two axes on a quantal dose response curve

Answer 5

X: drug dose
Y: % of individuals that respond to the drug at that dose

Question 6

Non-cumulative vs cumulative quantal dose response curve

Answer 6

Non-cumulative: number of individuals responding to a drug only at that dose (bell shaped)
Cumulative: number of individuals responding to a drug at that doses and all doses lower (sigmoidal shaped)

Question 7

How to interpret therapeutic index

Answer 7

Higher index = safer drug

Question 8

Therapeutic window

Answer 8

Range of doses of a drug in a body that provides for the safe and effective therapy

Question 9

Potency

Answer 9

Amount of drug required to produce a specific pharmacological effect

Question 10

What does a low ED50 mean?

Answer 10

More potent drug

Question 11

Efficacy

Answer 11

Max pharmacological effect a drug can produce

Question 12

What does higher Emax mean?

Answer 12

More efficacious drug

Question 13

Covalent vs non-covalent bonds in drug receptor binding

Answer 13

Covalent: irreversible

Non-covalent: reversible, most drugs use this

Question 14

Three non-covalent bonds, from strongest to weakest

Answer 14

1. Ionic bonds
2. Hydrogen bonds
3. Hydrophobic interactions

Question 15

With high affinity, does one need more or less drug to produce a response?

Answer 15

Less drug needed

Question 16

KD

Answer 16

Equilibrium dissociation constant - describes affinity of a drug

Question 17

What does lower KD mean?

Answer 17

Higher affinity of a drug for a receptor

Question 18

What happens to the KD ratio with a more selective drug?

Answer 18

Higher ratio (KD off target / KD target)

Question 19

Do more or less selective drugs have more side effects

Answer 19

Less selective -> more side effects

Question 20

Intrinsic activity

Answer 20

Ability of a drug to change a receptor function and produce a physiological response upon binding to receptor

Question 21

Antagonists

Answer 21

Bind receptor but do not change its function, only prevent activation (dont have intrinsic activity)

Question 22

When all receptors are full with partial agonists, what happens?

Answer 22

Sub-maximal pharmacological effect

Question 23

Inverse agonists

Answer 23

Produce an effect opposite to an agonist

Question 24

Three types of antagonism and describe them

Answer 24

1. Pharmacologic: action at same receptor as endogenous ligand
2. Chemical: chemical makes other drug unavailable
3. Physiologic: occurs between endogenous pathways regulated by different receptors

Question 25

Two types of non-competitive antagonists

Answer 25

1. Irreversible

2. Allosteric

Question 26

Why would you use an antagonist as a drug?

Answer 26

Block actions of endogenous ligands at receptors

Question 27

Five major classes of drug targets

Answer 27

1. Membrane receptors
2. Nuclear receptors
3. Ion channels
4. Transport proteins
5. Enzymes

Question 28

Most common receptor type targeted by drugs

Answer 28

GPCRs