Pharmacology Flashcards

1
Q

Define pharmocokinetics

A

What the body does to the drug

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

Define pharmoacodynamics

A

What the drug does to the body

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

What are different methods of drug transfer across membranes

A
Aqueous diffusion
Passive lipid diffusion
Facilitated diffusion
Pinocytosis (budding of membrane to ingest into cell)
Active transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What factors affect rate of membrane transport according to ficks law?

A
Diffusion coefficient
Surface area
Membrane thickness
Partition coefficient (how drug distributes in liquid vs oil)
Concentration gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the methods of drug disposition?

A

Absorption
Distribution
Metabolism
Excretion

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

Define bioavailability

A

Fraction of dose reaching systemic circulation after administration compared to same dose given intravenously

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

What factors affect drug absorption?

A

Route of administration

Formulation

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

How does ionisation affect absorption of drugs?

A

Drugs are weak acids or bases, with ionisation affected by their pKa and surrounding pH
pH changes with infection etc
Non-ionised drugs- cross by passive diffusion
Ionised drugs- cross by transport mechanisms, facilitated diffusion or pinocytosis

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

List routes of drug administration and how it affects drug absorbtion

A

Intravenous- rapid absorption as directly into systemic circulation
Intramuscular- speed dependent on local blood flow and diffusion of muscle
Subcutaneous- slower and less predictable, depends on site, temperature, hydration etc.
Oral- mainly absorbed in small intestine, effected by GI motility, splanchnic blood flow, drug size etc., will undergo first pass metabolism
Inhalational- causes local effect or absorbed into circulation
Epidural, transmucosal, transepithelial- effects at site of admin, can be taken up systemically

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

What is meant by first pass metabolism?

A

Concentration of drug given orally is reduced before entering systemic circulation

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

What determines volume of drug distribution?

A

Amount administered and concentration of the drug in plasma

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

How does protein and tissue binding of a drug affect its distribution?

A

Albumin binds weak acids
Alpha-1-acid glycoprotein binds weak bases
Only unbound drugs can interact and cause effect on the body
(Tissue binding can be specific or non-specific)

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

How does organ blood flow, membrane permeability and drug solubility effect drug distribution?

A

Drugs initially go to tissues with high blood flow

Highly lipid soluble drugs will accumulate in fat

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

Define clearance

A

Volume of plasma from which drug is completely removed per unit of time

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

Define half-life

A

Time taken for plasma concentration to fall 50% of original level

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

What factors affect drug metabolism and excretion?

A

Clearance and half life

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

Define biotransformation

A

Alteration of substance within the body

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

Name the stages of drug metabolism

A

Biotransformation

Excretion

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

Why do most drugs need to undergo biotransformation before they can be excreted by the kidneys?

A

Lipophilic and highly bound

Kidneys excrete polar water soluble compounds most easily

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

What is the main organ of metabolism and how does it work?

A

Liver
Phase one- convert drug to polar metabolites allowing renal excretion
Phase two- conjugation/combining with substrates

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

What can be the effects when drugs are activated by metabolism?

A

Become active drug
Produces active metabolites causing further effects
Produces toxic metabolites

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

What is the most common excretion of drugs and how does it work?

A

Renal
Active- tubular secretion
Passive- glomerular filtration

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

What other methods of drug excretion are there other than renal?

A

Biliary system
Exhalation
GI system

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

What is meant by enterohepatic circulation?

A

Pathway drugs take until plasma concentration drops

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

Describe the pathway taken by drugs in enterohepatic circulation

A
Drug metabolised by liver
Biliary excretion
Deglucorinidation/reverse metabolism by gut microflora
Reabsorption in gut
Drug metabolised by liver
26
Q

List the stages a drug takes when causing an effect on the body

A

Drug site of action
Pharmacological effect
Clinical response- therapeutic effect and toxicity

27
Q

Define clinical response

A

What is seen due to drug

28
Q

Define therapeutic effect

A

Desired effect of a drug

29
Q

Define toxicity

A

Side effects of a drug

30
Q

List non-cellular mechanisms of effect of drugs

A

Physical
Chemical
Physiochemical
Modification of body fluid composition

31
Q

List cellular mechanisms of effects of drugs

A

Alter physicochemical mechanisms of the body
Cell membrane structure and function modification
Enzyme inhibition
Receptor mediation

32
Q

Define therapeutic index

A

Maximum non-toxic/minimum effective dose of a drug based off 50% of animals

33
Q

Why is using therapeutic index for drugs flawed?

A

Effective dose will vary depending on what is being treated

Wont account for idiosyncratic drug reactions (reactions unrelated to dose)

34
Q

Define affinity

A

How well a drug binds to its receptor

35
Q

Define intrinsic activity/efficiacy

A

Magnitude of effect once bound, measured 0-1

36
Q

Define agonist and state an example

A

Generate maximal response when bound to a receptor, have high affinity and intrinsic activity/efficacy
Morphine

37
Q

Define partial agonist and state an example

A

Intrinsic activity less than 1 so cant generate maximal response even with full receptor occupancy
Buprenorphine

38
Q

Define inverse agonist and state an example

A

Drug binding exerts opposite effect compared to endogenous agonist
Antihistamines

39
Q

Define antagonist and state and example

A

Exhibits affinity without intrinsic activity

Atipamezole

40
Q

Define potency

A

How much of the drug is needed to cause wanted response

41
Q

List the molecular targets for drugs

A
Receptors
Enzymes
Transporters
Ion channels
Nucleic acid
42
Q

Define ligand

A

Substance that forms complex with boimolecule

43
Q

Define receptors

A

Protein interacting with extracellular physiological signals, converting them to intracellular effects

44
Q

Name an example of a receptor for drugs

A

Mu opioid receptor

45
Q

What is the difference in effect of agonists and antagonists on receptors?

A

Agonists- cause direct effects (ion channel opening/closing) or transduction mechanisms (enzyme activation or inhibition, ion channel modulation, DNA transcription) to cause effect
Antagonists- no effect caused or prevent agonist binding preventing or reversing effect of agonist

46
Q

List the 4 main types of receptor

A

Ligand gated ion channels (ionotropic- membrane bound)
G-protein coupled receptors (metabotropic- initiates metabolic processes to modulate cell activity)
Kinase linked receptors
Nuclear receptors

47
Q

What are the characteristics of ligand gated ion channel receptors? (Speed of action, how they cause effect, example)

A

Act in milliseconds
Hyperpolarise or depolarise
Nicotinic ACh receptor in neuromuscular junction post synaptic membrane

48
Q

What are the characteristics of G-protein coupled receptors? (Speed of action, how they cause effect, example)

A

Act in seconds
Change membrane excitability or second messengers cause effect leading to cellular effects
Muscarinic ACh receptor in smooth muscle of blood vessels

49
Q

What are the characteristics of kinase linked receptors? (Speed of action, how they cause effect, example)

A

Act in hours
Protein phosphorylation leading to protein synthesis and cellular effects
Cytokine recpetors

50
Q

What are the characteristics of nuclear receptors? (Speed of action, how they cause effect, example)

A

Act in hours
Gene transcription and protein synthesis causing cellular effects
Oestrogen receptor

51
Q

How do enzymes act as drug target and what is an example?

A

Become activated by agonists and inhibited by antagonists

Cyclooxygenase enzyme

52
Q

What effect do enzymes have on prodrugs?

A

Converts to active drug undergoing reaction to produce more effect on the body

53
Q

Define prodrug

A

Molecules converted into active drug

54
Q

How do transporters work as drug target and what is an example?

A

Agonists bind and move into cell
Antagonists bind and block transporter
Insulin

55
Q

How do ion channels work as drug targets and what is an example?

A

Agonists increase or decrease probability of opening
Antagonists block channel
Local anaesthetics on nerves channels

56
Q

How do nucleic acids work as drug targets and what is an example?

A

Alter gene transcription

Chemotherapy drugs

57
Q

How are antimicrobial agents classified?

A

Type of organisms effective against

Either bacteriostatic or bactericidal

58
Q

Define bacteriostatic

A

Prevent bacterial multiplication to remove infection by immune system

59
Q

Define bactericidal

A

Kill bacteria

60
Q

What are antibiotic dependent on to be effective?

A

Concentration- outcome related to peak antibiotic concentration at site of infection compared to minimum inhibitory concentration
Time- concentration needs to be above minimum for enough time between doses

61
Q

What are the mechanisms of action of antibiotics?

A

Cell wall- ruptures
Cytoplasmic membrane- altered structure
Nucleic acid metabolism- interfere with DNA replication or repair

62
Q

Explain the process of antibiotic therapy

A

Make diagnosis
Remove barriers which prevent antibiotics working
Decide if therapy is needed
Select best drug
Administer drug at best frequency and route
Test if drug has worked