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Flashcards in Pharmacology Deck (71)
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1

Define pharmacodynamics?

What a drug does to the body (biological effects and mechanisms of action)

2

Define pharmacokinetics?

What the body does to a drug (absorption, distribution, metabolism and excretion of drugs and their metabolites)

3

What is the medical definition of a drug?

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

4

What are receptors?

Macromolecules that mediate the biological actions of hormones and neurotransmitters

5

What are agonists?

Drug that binds to receptor to produce a response

6

What are antagonists?

Drug that blocks the action of agonists

7

What is the affinity of a drug?

Binding step
Strength of association between ligand and receptor

8

What is the efficacy of a drug?

Activation step
The ability of an agonist to evoke a cellular response

9

Do agonists possess affinity or efficacy?

Both

10

Do antagonists possess affinity or efficacy?

Affinity only

11

What is the speed of reaction of a drug with low affinity?

Slow

12

What is the speed of reaction of a drug with high affinity?

Fast

13

What is the level of response of a drug with low efficacy?

Low

14

What is the level of response of a drug with high efficacy?

High

15

What is the relationship between agonist concentration and receptor occupancy?

Hyperbolic relationship showing saturation

16

What is the EC50?

Concentration of agonist which produces a half maximal response

17

What is the relationship between agonist concentration and response?

Sigmoidal, semi-logarithmic plot

18

Why is the sigmoidal plot better than that of the hyperbolic plot?

Encompasses a greater range of values
Gives a more accurate reading of the EC50

19

What is the potency of a drug?

The concentration of a drug required to produce an effect
(i.e. the more drug needed, the less potent it is)

20

How would a partial agonist be distinguished on a sigmoidal plot?

It will have less than 100% maximal response

21

How does competitive antagonism occur?

Agonist and antagonist bind to the same site (orthosteric)

22

How does non-competitive antagonism occur?

Antagonist binds to a separate allosteric site
Causes a conformational change in receptor change - even if agonist binds, receptor remains inactive in presence of antagonist

23

What is the effect of adding a non-competitive antagonist on the agonist-response curve?

No shift
Maximal response depressed
Slope clearly flattened

24

What is the effect of adding a competitive antagonist on the agonist-response curve?

Parallel shift to the right
No depression of maximal response

25

What are the four phases involved in drug disposition?

Absorption
Distribution
Metabolism
Excretion

26

What is absorption?

The process by which a drug enters the body, where the GI tract is considered outside

27

What is distribution?

The process by which a drug leaves the circulation an d enters the tissues perfused by blood

28

What is metabolism?

The process by which tissue enzymes catalyse the chemical conversion of a drug to a more polar form that is more readily excreted

29

What is excretion?

The processes that remove the drug from the body

30

How does solubility affect drug absorption?

Drug must dissolve in order to be absorbed