**_💊Pharmacology💊 - Pharmacodynamics & Pharmacokinetics Flashcards

1
Q

What is the difference between pharmacology and therapeutics?

A

Pharmacology is the study of drug action, how a drug interacts with living organisms and how this influences physiological function
Therapeutics is concerned with drug prescribing and the treatment of disease, more focused on the ‘patient’

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2
Q

What is the difference between pharmacodynamics and pharmacokinetics?

A

Pharmacodynamics deals with ‘what the drug does to the body’ and pharmacokinetics deals with ‘what the body does to the drug’

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3
Q

What 3 things must be considered when evaluating the effect a drug has on the body?

A

Where is the effect produced?
What is the target for the drug?
What is the response that is produced after interaction with this target?

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4
Q

What must a drug do in order to have an effect?

A

Be bound to a target

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5
Q

Are drugs often limited to just 1 effect on the body?

A

No!

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6
Q

What effect does cocaine have?

A

Produces a euphoric high
Also, can be an effective local anaesthetic

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7
Q

Where in the body is the euphoric effect produced by cocaine?

A

The nucleus accumbens

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8
Q

What is the specific cellular target of cocaine?

A

Dopaminergic neurones in the nucleus accumbens

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9
Q

What is the specific molecular target of cocaine?

A

The dopamine reuptake protein on the pre-synaptic terminal of dopaminergic neurones

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10
Q

What is the response that is produced after cocaine’s interaction with it’s target?

A

Cocaine will BLOCK the dopamine reuptake protein. This means that dopamine is not removed from the synapse as quickly, and is thus more available to bind to the dopamine (D1) receptor. Activation of this receptor is what causes euphoria

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11
Q

What are the 4 different types of drug targets?

A

Receptors
Enzymes
Ion channels
Transport proteins

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12
Q

What type of target does aspirin bind to?

A

Enzyme

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13
Q

What is the effect of aspirin?

A

Aspirin binds to the ‘enzyme’ cyclooxygenase and blocks the production of prostaglandins

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14
Q

What type of target do local anaesthetics bind to?

A

Ion channels

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15
Q

What is the effect of local anaesthetics?

A

Local anaesthetics block sodium ‘ion channels’ and thus prevent nerve conduction

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16
Q

What is the target of Prozac (anti-depressant)?

A

Carrier proteins

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17
Q

What is the effect of Prozac?

A

Prozac (Anti-depressant) block serotonin ‘carrier proteins’ and prevent serotonin being removed from the synapse

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18
Q

What is the target of nicotine?

A

Receptor

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19
Q

What is the effect of nicotine?

A

Nicotine binds to and activates the nicotinic acetylcholine ‘receptor’

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20
Q

Why is selectivity important for a drug?

A

So that it only effects the desired target
Minimal side and adverse effects

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21
Q

Which 3 molecules are very structurally similar and are found in synapses?

A

Dopamine, noradrenaline, serotonin

22
Q

What problem does these 3 molecules being very structurally similar pose?

A

A drug that can interact with the receptor for one of them may be able to interact with receptors for the other two

23
Q

What is the significance of drug dose on its specificity?

A

The higher the dose, the more likely a drug is to have an effect at a secondary target site
Site A sees an effect at a low dose, then as dose increases a threshold is reached where an effect is now seen at site B

24
Q

What are the different types of drug-receptor interactions?

A

Electrostatic interactions
Hydrophobic interactions
Covalent bonds
Stereospecific interactions

25
Q

Describe electrostatic interactions

A

This is the most common mechanism and includes hydrogen bonds and Van der Waals forces

26
Q

Describe hydrophobic interactions

A

This is important for lipid soluble drugs

27
Q

Describe covalent bonds

A

these are the least common as the interactions tend to be irreversible

28
Q

Describe stereospecific interactions

A

A great many drugs exist as stereoisomers and interact stereospecifically with receptors

29
Q

What is the affinity of a drug?

A

The affinity of a drug determines strength of binding of the drug to the receptor, affinity is strongly linked to receptor occupancy

30
Q

What is the efficacy of a drug?

A

The ability of an individual drug molecule to produce an effect once bound to a receptor

31
Q

What is the difference between affinity and efficacy?

A

Affinity refers to the likelihood that a molecule of a drug will be bound to a receptor, the efficacy refers to whether the binding of a drug has an effect or not. When a drug occupies a receptor, it does not necessarily produce one standard unit of response

32
Q

What type of molecule would have high affinity but no efficacy?

A

A receptor antagonist
When bound to that receptor, it is effectively blocking that receptor

33
Q

What type of molecule would have affinity but sub-maximal efficacy?

A

A partial agonist
When bound it can produce a partial response, but not a maximal response

34
Q

What type of molecule would have high affinity and high/maximal efficacy?

A

A (full) agonist
When bound to a receptor, produces a maximal response

35
Q

What is the potency of a drug?

A

The concentration or dose of a drug required to produce a defined effect

36
Q

What is the standardised measure of potency?

A

The concentration or dose of a drug required to produce a 50% tissue response

37
Q

What are the 4 major pharmacokinetic factors?

A

Absorption
Distribution
Metabolism
Excretion

38
Q

Define absorption

A

The passage of a drug from the site of administration into the plasma

39
Q

What is bioavailability?

A

The fraction of the initial dose that gains access to the systemic circulation

40
Q

What is the significance of distribution in pharmacokinetics?

A

Different tissues will be exposed to different amounts of the drug depending on several factors

41
Q

What are the factors that effect distribution of a drug in body tissues?

A

Regional blood flow
Plasma protein binding
Capillary permeability
Tissue localisation

42
Q

How does regional blood flow effect drug distribtution?

A

Different tissues receive a greater proportion of blood flow, so these tissues will receive more exposure to the drug

43
Q

How does plasma protein binding effect drug distribution?

A

Drugs with a higher affinity to plasma proteins are unable to diffuse out of blood (only free drug molecules can) so are not able to reach their target sites

44
Q

Why is metabolism important in drug pharmacokinetics?

A

To make drugs less lipid soluble, allowing for easier excretion

45
Q

What are the two phases in drug metabolism?

A

Phase 1 – main aim is to introduce a reactive group to the drug
Phase 2 – main aim is to add a conjugate to the reactive group
Both stages together act to decrease lipid solubility which then aids excretion and elimination

46
Q

What is the purpose of phase 1 of drub metabolism?

A

The end result of phase 1 metabolism is to produce metabolites with functional groups that serve as a point of attack for the conjugating systems of phase 2

47
Q

What is the purpose of phase 2 of drug metabolism?

A

The attachment of a substituent group, and the resulting metabolite is nearly always inactive and far less lipid soluble than the phase 1 metabolite

48
Q

What are the main routes of drug excretion?

A

The lungs (such as alcohol, this forms the basis of the breathalyser test)
Breast milk ( this is why care needs to be taken that drugs excreted in milk do not affect the baby)
Kidneys (in urine)
Liver (in bile)

49
Q

What are the 3 major routes of excretion from the kidney?

A

Glomerular filtration
Active tubular secretion (or reabsorption)
Passive diffusion across tubular epithelium

50
Q
A