Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Principles > Pharmacology > Flashcards

Pharmacology Flashcards

1
Q

Define pharmacodynamics?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define pharmacokinetics?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the medical definition of a drug?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are receptors?

A

Macromolecules that mediate the biological actions of hormones and neurotransmitters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are agonists?

A

Drug that binds to receptor to produce a response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are antagonists?

A

Drug that blocks the action of agonists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the affinity of a drug?

A

Binding step

Strength of association between ligand and receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the efficacy of a drug?

A

Activation step

The ability of an agonist to evoke a cellular response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Do agonists possess affinity or efficacy?

A

Both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Do antagonists possess affinity or efficacy?

A

Affinity only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

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

A

Slow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

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

A

Fast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

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

A

Low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

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

A

High

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the relationship between agonist concentration and receptor occupancy?

A

Hyperbolic relationship showing saturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the EC50?

A

Concentration of agonist which produces a half maximal response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the relationship between agonist concentration and response?

A

Sigmoidal, semi-logarithmic plot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

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

A

Encompasses a greater range of values

Gives a more accurate reading of the EC50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the potency of a drug?

A

The concentration of a drug required to produce an effect

i.e. the more drug needed, the less potent it is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

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

A

It will have less than 100% maximal response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How does competitive antagonism occur?

A

Agonist and antagonist bind to the same site (orthosteric)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does non-competitive antagonism occur?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

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

A

No shift
Maximal response depressed
Slope clearly flattened

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

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

A

Parallel shift to the right

No depression of maximal response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the four phases involved in drug disposition?

A

Absorption
Distribution
Metabolism
Excretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is absorption?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is distribution?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is metabolism?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is excretion?

A

The processes that remove the drug from the body

30
Q

How does solubility affect drug absorption?

A

Drug must dissolve in order to be absorbed

31
Q

How does chemical stability affect drug absorption?

A

Protein based drugs would be digested before absorption and so cannot be given orally

32
Q

How does the lipid to water partition coefficient affect drug absorption?

A

Drug must be able to dissolve in both lipid and water (amphipathic)
Drugs with higher lipid solubility will have a higher membrane concentration and so cross the membrane quicker

33
Q

How does the degree of ionisation of a drug affect drug absorption?

A

Only unionised forms will diffuse readily across membrane

34
Q

What is the Henderson-Hasselbalch equation?

A

Acid
pKa - pH = log(HA/A-)

Alkali
pKa - pH = log(BH+/B)

Calculates the proportions of ionised and unionised drugs

35
Q

In what environment do acid drugs become less ionised?

A

In an acidic environment

36
Q

In what environment do basic drugs become less ionised?

A

In a basic environment

37
Q

What factors affect GI absorption?

A 
GI motility 
pH of absorption site 
Blood flow to site 
Way in which the tablet has been manufactured 
Physiochemical interactions 
Presence of transporters in the membrane
38
Q

What is the oral availability of a drug?

A

The fraction go the drug that reached the systemic circulation after oral ingestion

39
Q

What is the systemic availability of a drug?

A

The fraction of the drug that reaches the systemic circulation after absorption

40
Q

What are the enteral routes of drug administration (GI)?

A

Oral
Sublingual
Buccal
Rectal

41
Q

What are the parenteral routes of drug administration (non GI)?

A 
Intravenous 
Intramuscular 
Subcutaneous 
Inhalation 
Topical
42
Q

What is the therapeutic ratio?

A

Maximum Tolerated Dose / Minimum Effective Concentration

The higher the ratio, the safer the drug

43
Q

What is Kabs?

A

The absorption rate constant

44
Q

What is Kel?

A

The elimination rate constant

45
Q

How is the initial dose of an IV drug calculated?

A

Mass / Volume

C0 = D / Vd

46
Q

By how many half lives will the majority of drugs have left the body?

A

Five

47
Q

What drives the rate at which drugs leave the body?

A

Drug concentration

48
Q

For drugs exhibiting first order kinetics, what is the effect of doubling the dose of a drug?

A

Adds one half life to its duration of therapeutic effect
Doubles the steady state plasma concentration
Does not alter the time for a drug to reach steady state

49
Q

What is the clearance of a drug?

A

The volume of plasma cleared of drug in unit time

50
Q

Why is clearance important?

A

Determines the maintenance dose rate

51
Q

How is rate of elimination calculated?

A

Clearance x Plasma Concentration

52
Q

What is the steady state of a drug, and how long does it generally take to reach?

A

Rate of drug administration = rate of drug elimination

Approximately 5 half lives

53
Q

What is the volume of distribution of a drug?

A

The volume into which a drug appears to be distributed with a concentration equal to that of the plasma

54
Q

What is the loading dose?

A

An initial higher dose of drug given at the start of treatment before stepping down to a lower maintenance dose

55
Q

Why is a loading dose used?

A

To decrease the time to steady state for drugs with long half loves

56
Q

What is the half life of a drug?

A

The time taken for the concentration of drug in the plasma to halve

57
Q

What are first order kinetics?

A

Where the rate of elimination is directly proportional to drug concentration

58
Q

What are zero order kinetics?

A

Where the rate of elimination is constant, rather than proportional to the concentration of the drug

59
Q

What are the aims of drug metabolism?

A

Convert drugs to more polar metabolites which are not readily absorbed in the kidney, and so are excreted
Convert drugs to metabolites that are usually less pharmacologically active

60
Q

What is the main organ of drug metabolism?

A

Liver

61
Q

What occurs during phase 1 of metabolism in the liver?

A

Oxidation, reduction, hydrolysis
Makes drugs more polar
Adds chemically active group permitting conjugation in phase II

62
Q

What occurs during phase 2 of metabolism in the liver?

A

Conjugation

Adds an endogenous compound increasing polarity

63
Q

What are the cytochrome P450 family of Monooxygenases and what is their role in metabolism?

A

Haem proteins located in the ER of the liver

Mediate oxidation reactions in phase I of metabolism

64
Q

How does the Monooxygenase P450 cycle cause oxidation?

A

Drug enters as substrate
Molecular oxygen enters cycle
One atom of oxygen is added to drug to yield the hydroxyl product
The other oxygen atom gives water

65
Q

What is glucuronidation?

A

Common phase II reaction involving the transfer of gulcuronic acid to electron wish atoms of the substrate

66
Q

What three basic processes are involved in renal excretion of drugs?

A

Glomerular filtration
Active tubular secretion
Passive reabsorption by diffusion across the tubular epithelium

67
Q

How can a drug avoid glomerular filtration?

A

By binding to a large plasma protein

68
Q

What are the two independent transporter systems which actively secret drugs into the lumen of the nephron?

A

Organic anion transporter = Acidic drugs

Organic cation transporter = Basic drugs

69
Q

What is potentially the most effective mechanism for drug elimination by the kidney?

A

Tubular secretion

70
Q

How can drugs which are highly protein bound be excreted?

A

Tubular secretion

71
Q

What factors influence tubular reabsorption of a drug?

A

Lipid solubility
Polarity
Urinary flow rate
Urinary pH

Principles (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions