Basic Principles of Pharmacology Flashcards Preview

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Flashcards in Basic Principles of Pharmacology Deck (40):
1

How does a drug work

By binding to something (e.g. receptors, enzymes, ion channels or transporters)

2

Define pharmacodynamics

The study of how drugs act on the living body

3

Define agonist

A ligand that binds and induces a response

4

Define full agonist

An agonist that produces a maximal effect. It has high efficacy

5

Define partial agonist

An agonist that produces a submaximal effect. It has an intermediate efficacy

6

What is the difference between a full and partial agonist

A full agonist produces a maximal effect, whilst a partial agonist produces a submaximal effect

7

What shaped dose-response curve does a full agonist give

Sigmoidal (S shaped)

8

What shaped dose-response curve does a partial agonist give

Sigmoidal (S shaped), but more shallow than a full agonist

9

Define a competitive antagonist

A ligand that competes with the agonist to bind to the receptor

10

Define a non-competitive antagonist

A ligand that binds to a site that is not the active site and alters the receptor such that the agonist cannot bind

11

Define a reversible antagonist

An antagonist that can be washed out. Binding is not permanent

12

Define an irreversible antagonist

An antagonist that cannot be washed out. Binding is permanent.

13

What is the dose-response curve for a reversible competitive antagonist

Parallel shift to the right. No change in maximal response

14

What is the dose-response curve for an irreversible competitive antagonist

No shift. Maximal response reduced

15

What is the dose-response curve for a reversible non-competitive antagonist

No shift. Maximal response reduced. No change in EC50 value

16

What is the dose-response curve for an irreversible non-competitive antagonist

No shift. Maximal response reduced. No change in EC50 value. Maintains sigmoidal shape.

17

Define physiological antagonism

A ligand that acts in a different place. Causes a different bodily function to counteract the undesirable one

18

Define chemical antagonism

An antagonist that reduces the concentration of an agonist by forming a chemical complex with it

19

Define pharmacokinetic antagonism

An antagonist that affects absorption, distribution, metabolism or elimination

20

Define affinity

The ability of the drug to bind to the target

21

Define efficacy

The ability of the drug to induce a conformational change (activation)

22

What is the affinity and efficacy of an agonist

Full agonists have high efficacy. Partial agonists have intermediate efficacy

23

What is the affinity and efficacy of an antagonist

They have no efficacy because no response is induced.

24

How does a ligand gated ion channel initiate a biological response

Agonist binding causes a conformational change which causes the ion channel to open

25

Give an example of a ligand gated ion channel

Nicotinic acetylcholine receptor

26

How does a GPCR initiate a biological response

Agonist binding causes stimulation of a secondary messenger signalling cascade

27

How does a receptor tyrosine kinase initiate a biological response

Similar to a GPCR. Except the intracellular domain contains tyrosine kinase

28

How does an intracellular hormone receptor initiate a biological response

Ligand activates transcription factors. Factors regulate gene expression by interacting with specific DNA sequences

29

What are the four key stages of pharmacokinetics

Absorption, Distribution, Metabolism, Excretion

30

Define drug absorption

How a drug enters the blood stream

31

What does drug distribution depend on

Physical and chemical properties of the drug. The drugs ability to penetrate cell membranes

32

Define the first pass effect and its importance

When drugs pass through the liver they tend to be converted to less active alternatives. Most drugs need to be able to be active after the first pass

33

Define EC50 value

The concentration of agonist needed to produce 50% of the maximal response

34

Define IC50 value

The concentration of antagonist needed to inhibit 50% of maximal response

35

Define ED50 value

Minimum dose required to show desired activity in half of the tested population after a specific duration of time

36

Define LD50 value

The dose required to kill half of the members of the tested population (LD = lethal dose)

37

Define therapeutic index

The ratio of ED and LC.

38

What is the importance of the therapeutic index

Defines a useable drug dose which will show activity, but not kill.

39

What are the four stages of a clinical trial

1 - check for safety
2 - check for efficacy
3 - confirm findings in a larger population group
4 - test long-term safety in diverse patient population

40

Define 'drug'

A substance of known chemical structure, which when administered to a living organism produces a biological effect