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MBBS - Year 1 > Intro to pharmacology > Flashcards

Flashcards in Intro to pharmacology Deck (73)
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1
Q

Pharmacology

A

Science of drug action

2
Q

Drug

A

Anything w/ positive or desired effect

Substance used in diagnosis, treatment or prevention of disease or as a component of a medication

3
Q

Poison

A

Anything w/ negative or undesired effect

4
Q

Legal status of drugs

A

POM
PM
GSL

5
Q

POM

A

Prescription only medication

6
Q

PM

A

Pharmacy medication

7
Q

GSL

A

General sales medication

8
Q

Branches of pharmacology

A

Pharmacokinetics

Pharmacodynamics

9
Q

Pharmacokinetics

A

How the body affects the drug

10
Q

Pharmacodynamics

A

How the drug affects the body

11
Q

Drugs can be …

A

Agonist

Antagonist

12
Q

Agonist

A

Activate receptors and elicit a response e.g. drugs, hormones, neurotransmitters bitter, signalling molecules

13
Q

Antagonist

A

Prevent (block) effect of agonist; can be competitive or non-competitive

14
Q

Examples of agonist/antagonist interactions

A

Morphine is released at a synapse (agonist) and naloxone fits into the dips on the other neurone (antagonist) blocking the morphine

15
Q

Receptors

A

Proteins located on cell membranes, respond to endogenous compounds (hormones)

16
Q

Transport systems

A

Ion channels, either voltage gated (Ca2+, K+, Na+) or ligand gated

17
Q

G coupled proteins

A

Located in cell membranes and bounds extracellular substances to an intracellular molecule

18
Q

Affinity

A

How well does the drug bind to receptor

19
Q

What does drug affinity depend on

A

Conc of drug [D]

20
Q

What does removal of a drug depend on

A

How well it bound in 1st place

21
Q

Receptor binding

A

How many receptors are occupied

22
Q

How is rship between drug conc and receptor binding calculated

A

p = [D]/ [D] + Kd

23
Q

Dose

A

How much drug is needed for therapeutic response

24
Q

What should drug + receptor =

A

Chemical response but this depends on efficacy

25
Q

Efficacy

A
2 drugs 
Same concept 
Same receptor binding ability (affinity)
Different efficacy 
Diff chemical effects
26
Q

Examples of drugs w/ diff efficacy

A

Benzodiazepines, lorazepam and temazepam have a 10-fold diff in dose

27
Q

Key point about efficacy and dosage

A
Not all drugs in the same class and receptor site will have similar doses 
As a result, medication ha sits own currency
28
Q

Stages of pharmacokinetics

A

Absorption
Distribution
Metabolism (after body realises drug is exogenous)
Excretion

29
Q

Absorption in pharmacokinetics

A

Getting drug into body - so it can work
Everything given via mouth will go through dissolution phase
Pass through gut wall into bloodstream —> even distribution around the body

30
Q

What does absorption depend on

A

Drug solubility - lipophilic or hydrophilic

31
Q

Why is drug solubility important

A

Allows us to decipher how to get the drug into the body

32
Q

Lipid soluble drugs

A

Pass through the gut and enter the bloodstream a lot quicker e.g. hormones

33
Q

What happens when drugs are distributed unto water compartments in the blood

A

Exposed to plasma proteins - where once bound can become ineffective (unable to traverse cell membranes)

34
Q

Routes of administration

A
Oral (po)
Inhaled (inh)
Topical (top)
Sub lingual (s/l)
Rectal (pr)
Parental
35
Q

Oral administration

A

po

Most common, ease of administration

36
Q

Inhaled administration

A

Volatile anaesthetics/ local delivery in asthma

37
Q

Topical administration

A

Skin/eyes/ears - local delivery

38
Q

Sub lingual administration

A

Rapid onset action

Under tongue

39
Q

Example of drug given sub lingually

A

GTN - Glyceryl trinitrate

Used to treat angina

40
Q

Rectal administration

A

Bypass portal circulation

41
Q

Parental administration

A

Bypassing GI system

Straight into blood stream

42
Q

Types of parental administration

A
Subcutaneous 
Intramuscular
Intravenous 
Transdermal
Implantation
43
Q

Subcutaneous parental administration

A

Drug infected into fat at 90 degrees, usually in stomach

44
Q

Drugs given by subcutaneous parental adminstarion

A

Insulin

LMWH

45
Q

LMWH

A

Low molecular weight heparin

46
Q

Intramuscular parental administration

A

Less common mode of administration
Usually done in big muscles e.g. thigh
Not many licensed to do
Used when we want to give drugs slowly i.e. give the drug in a neuroleptic preparation (depressing nerve functions)

47
Q

Transdermal parental administration

A

Continual drug release

48
Q

Examples of drugs given by transdermal parental administration

A

Morphine

NRT

49
Q

NRT

A

Nicotine replacement therapy

50
Q

Intravenous parental administration

A

100% bioavailability

Good for infusions, rapid access and drug delivery in large volumes

51
Q

Bioavailability

A

% unchanged drug that reaches the systemic circulation

52
Q

Implantation parental administration

A

Hormones/steroids

Targeted and continual drug release

53
Q

What allows us to figure out the dose of a drug

A

Half life
Vd
Clearance

54
Q

Half life

A

Time it takes drug conc to drop to half of orig

55
Q

Vd

A

Volume of distribution

How much volume the drug has to distribute itself into

56
Q

Clearance

A

Volume of plasma/ blood cleared of drug

57
Q

Metabolism in pharmacokinetics

A

Occurs throughout body - usually in liver (lipophilic)

Important because determines therapeutic and toxic effects of drugs and allows you too optimise therapy, minimise harm

58
Q

Metabolites

A

Products of metabolism

Commonly less potent than the drug but can be more potent - prodrugs

59
Q

Prodrugs

A

The drug given to patient is partially active, once metabolised becomes a more potent agent that can provide local relief
Offshoots are active drugs

60
Q

Excretion in pharmacokinetics

A

Principally occurs in kidneys
Kidney = hydrophilic agents
Clearance via glomerular filtration

61
Q

Why do we aim to make drugs more hydrophilic

A

More water soluble –> more easily excreted by the kidneys

62
Q

Kinase linked receptors

A

Ligand binding activates an intracellular protein that triggers a cascade of phosphorylation reactions

63
Q

Selectivity

A

Propensity for a drug to bind to one target rather than an other

64
Q

Partial agonists

A

Activate the receptor but cannot produce a maximal signalling effect equivalent to that of a full agonist, even when all receptors are occupied

65
Q

Potency

A

Amount of drug required for a given response

66
Q

What do more potent drugs produce

A

Biological effects at lower doses

67
Q

ED 50

A

Dose producing half the value of the maximum response

68
Q

Therapeutic index

A

Ratio of the ED50 for therapeutic efficacy and for a major adverse effect
Indicates how much margin prescribers have when choosing a dose that will provide beneficial effects w/ out causing adverse effects

69
Q

Toxic effects

A

Adverse effects that occur at doses above the therapeutic range

70
Q

Side effects

A

Adverse effects that occur within the therapeutic range

71
Q

Hyper-susceptible effects

A

Adverse effects occurring below the therapeutic range

72
Q

Why do we have to give drugs on a frequent basis

A

The body will wash it out

73
Q

Factors to consider when choosing a drug

A
Absorption 
Distribution 
Metabolism 
Excretion
Efficacy 
Avoiding adverse effects and drug interactions 
Features of the disease 
Severity of disease 
Coexisting disease
Cost 
Patient adherence to therapy

Decks in MBBS - Year 1 Class (93):