1: Introduction to drug action

Question 1

What is pharmacodynamics?

Answer 1

What the drug does to the body

Question 2

What is pharmacokinetics?

Answer 2

What the body does to the drug

shifts it - kinetic

Question 3

What is a drug?

Answer 3

Any substance used in the treatment, prevention or diagnosis of disease

Question 4

For a drug to be useful as a therapeutic agent, it needs to act with a degree of ___.

Answer 4

selectivity

Question 5

Drugs act by ___ to molecules.

Answer 5

binding

Question 6

Name some proteins which drugs can bind to.

Answer 6

Enzymes

Carrier molecules

Channels

Receptors

Question 7

Drugs also bind to which acids?

Answer 7

DNA / RNA

Question 8

Under normal circumstances, which signal molecules bind to receptors?

Answer 8

Hormones

Neurotransmitters

Question 9

What are the two main classes of drug?

Answer 9

Agonists

Antagonists

Question 10

What is an agonist?

Answer 10

A molecule which binds to a receptor to produce a response

Question 11

What is an antagonist?

Answer 11

A molecule which blocks the action of an agonist

Question 12

Agonists bind to receptors which ___ them.

Answer 12

activates

Question 13

Is binding to a receptor the same as activating it?

Answer 13

No

Activation usually occurs as a result of binding, but they’re two separate steps

Question 14

What is affinity?

Answer 14

The strength of association between a ligand and a receptor

Question 15

Drugs with ___ affinity will dissociate from their receptor quickly.

Answer 15

low

Question 16

Drugs with ___ affinity will dissociate from their receptor slowly.

Answer 16

high

Question 17

What is efficacy?

Answer 17

The ability of an agonist to produce a cellular response

Question 18

___ efficacy produces a big cellular response.

Answer 18

High

Question 19

___ efficacy produces a small cellular response.

Answer 19

Low

Question 20

Do antagonists activate receptors?

What does this say about their efficacy?

Answer 20

No - only block them

Low efficacy

Question 21

Antagonists have ___ but not ___.

(affinity / efficacy)

Answer 21

affinity , efficacy

Question 22

Antagonists block receptor activation by ___.

Answer 22

agonists

Question 23

As agonist concentration increases, receptor occupancy ___.

Does this happen indefinitely?

Answer 23

increases

No - eventually saturation of all available receptors occurs

Question 24

What is EC₅₀?

Answer 24

The concentration of agonist which produces a HALF MAXIMAL RESPONSE

Question 25

When agonist concentration is plotted against % response, what shape is the graph?

Answer 25

Hyperbolic

Question 26

When agonist concentration is plotted logarithmically against % response, what shape is the graph?

Answer 26

Sigmoidal

Question 27

What is competitive antagonism?

Answer 27

Agonist and antagonist bind at the same orthosteric site - mutually exclusive and competitive

Question 28

What is non-competitive antagonism?

Answer 28

Antagonist binds to an allosteric site - no competition, but receptor is inactivated when antagonist binds