Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

1st Year - Principles > Pharmacology 1, 2 and 3 - Intro to drug action, drug movement in the body, elimination > Flashcards

Pharmacology 1, 2 and 3 - Intro to drug action, drug movement in the body, elimination Flashcards

1
Q

What are the 2 compromises of pharmacology and what do they mean?

A

Pharmacodynamics - what a drug does to the body (biological effects and mechanisms of action)Pharmacokinetics - what the body does to a drug (absorption, distribution, metabolism and excretion)

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

What selectively of drugs result from?

A

chemical structure of drugTarget recognising only ligands of a precise type

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

Examples of targets of drugs? (5)

A

enzymes, carrier molecule, ion channels, receptors, RNA/DNA

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

2 types of drugs acting on receptors and meaning?

A

Agonists - a drug that binds to a receptor and produces a cell responseAntagonists - a drug that blocks the actions of agonists

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

What is a ligand?

A

A molecule that binds to a receptor

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

Out of affinity and efficacy, what does an agonist and antagonist posses?

A

Agonist = affinity and efficacyAntagonist = affinity

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

How does an agonist work?

A

A conformational change occurs due to the presence of an agonist molecule making it act and therefore producing a biological response

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

Affinity?

A

Strength of association between ligands and receptor

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

Dissociation rate compared to affinity

A

Low affinity = high dissociation rate

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

What are the 2 things that determine affinity

A

Closer the fitNumber of bonds

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

Efficacy?

A

Ability of agonist to provoke a cellular response

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

Low efficacy?

A

Low ability to produce a cellular response

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

Relationship between receptor occupancy and agonist concentration?

A

As agonist conc. increases, receptor occupancy also increases

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

EC50?

A

Concentration of agonist which elicits a half maximal response

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

Concentration (or dose) response relationship - linear plot - relationship shape

A

Hyperbolic

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

Why is it easier to plot the concentration response relationship as the log of the agonist concentration?

A

It allows you to present data over a wider range of concentrations It is easier to see the max70% of the curve is a straight line

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

What shape is the response when the concentration response relationship is plotted as a semi-logarithmic plot?

A

Sigmoidal

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

What can a highly potent drug do?

A

Evoke a larger response at lower concentrations

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

What are partial agonists

A

Drugs that bind to receptors but only have partial efficacy meaning they cannot evoke the same response as a full agonist

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

Competitive antagonism?

A

Binding of agonist and antagonist occur at same (orthosteric) site

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

Non-competitive antagonism

A

Agonist binds to orthosteric site and antagonist binds to allosteric site (activation cannot occur if antagonist is bound)

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

Drug disposition?

A

The fate of drugs in the body

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

Determinants of drug disposition

A

AdsorptionDistributionMetabolismExcretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Adsorption?
The process by which a drug enters the body from its site of administration
26
Distribution
The process by which the drug leaves the circulation and enters the tissues perfused by the blood (once inside the tissue, further blood-independant distribution may occur)
27
Metabolism
The process by which tissue enzymes (particularly in the liver-hepatic metabolism) catalyse the chemical conversion of a drug to a more polar form that is more readily excreted by the body
28
Excretion
The process that removes the drug from the body (principally the kidneys - renal exertion)
29
Aside from the liver, where does metabolism also occur?
GI tract and lungs
30
Aside from the kidneys, where does excretion also occur?
Breath, sweat and milk
31
What is elimination (sum)?
metabolism + excretion
32
Where does most absorption occur?
in the Small intestines (due to large SA)
33
Where is ethanol absorbed
The stomach
34
name for when unchanged drugs leave the body via the faeces?
Egestion
35
3 physiochemical factors controlling drug absorption
Solubility (drug must be dissolved to be absorbed)Chemical stability (some drugs are destroyed by the stomach acid or enzymes in the GI tract)Lipid to water partition coefficient (rate of diffusion increases with lipid solubility of drug)
36
What does ampithatic mean?
Has both polar and non polar parts (drugs must be ampithatic)
37
In terms of weak/ strong acids/bases, what are many drugs
Weak acids and bases existing in both the ionised and unionised forms
38
pH=
pH=-log10[H+]
39
Out of ionised and unionised forms, what readily diffuses across the lipid bilayer
Unionised forms
40
What does the degree of ionisation of a drug depend on?
pKa of drug and local pH
41
pKa?
pH @ which 50% drug is ionised and 50% is unionised
42
What equation can be used to determine the proportion of ionised drug?
Henderson-Hassleback
43
Henderson hassleback equations for acid and base
Acid: pKa - pH = log(HA/A-)Base: pKa - pH = log (BH+/B)
44
As pH increases, are acid drugs increasingly or decreasingly ionised?
Increasingly
45
What is sometimes absorbed in the stomach acid?
Weak acids
46
Where does most absorption occur?
Small intestines (even weak acids)
47
Are weak acids and weak bases or strong acids and strong bases better absorbed?
Weak acids and weak bases
48
Factors affecting GI absorption? (6)
GI motility (rate of stomach emptying and movement through intestine) - modified by drugs and foodpH @ absorption siteBlood flow to GI tract (increased by food)Way in which tablet, capsule, etc. is manufactured (can be customised to release drugs at different rates/ sites)Physiochemical interactions (e.g. rate of absorption is modified by calcium rich food)Presence of transporters in membrane of epithelial cells of GI tract
49
Oral Availability? Equation?
Fraction of drug that reaches the systemic circulation after oral ingestion amount in systemic circulation/ amount administered
50
Systemic availability? Equation?
Fraction of drug that reaches the systemic circulation after absorptionamount in systemic circulation/ amount absorbed
51
First pass/ pre-systemic metabolism?
Drugs administered orally, once absorbed can be inactivated by enzymes in the gut wall and liver
52
2 categories of routes of drug administration?
ENTERAL-via GI tractParenteral - any route not via the GI tract
53
4 enteral routes of drug administration?
OralSublingual BuccalRectal
54
4 parenteral routes of drug administration?
IVintramuscularsubcutaneousInhalationTopical
55
What kind of drugs are able to move freely between the compartments of the body?
Free drugs
56
Volume of distribution?
Apparent volume in which a drug is dissolved
57
Vd=
Dose/ plasma concentraiton (for a drug administered IV)
58
Vd
Implies that the drug is retained in the vascular compartment
59
Vd
Implies that the drug is restricted to extracellular fluid
60
Vd>15L
Indicates distribution throughout total body water (or concentration in certain tissue)
61
What is the drug concentration that must be achieved to achieve an effect
Minimum effective concentration
62
What is the concentration level that causes significant adverse affects
Maximum tolerated concentration
63
What is the phase between MEC and MTC
therapeutic window
64
Therapeutic window of safe drugs
Large
65
Therapeutic ratio =?
MTC/MEC
66
Kabs?Kel?
Absorption rateElimination rate
67
If given IV, what is the initial concentration of drug equation?
Co = D/ Vd (C=m/V)
68
What factor does concentration of drug at a later time depend on (Ct)
Kel
69
What type of kinetics do most drugs exhibit
First order
70
Ct=
Ct= Coe^-Kel-t
71
Half life
Time taken for Ct to fall by 50%
72
What is t1/2 inversely related toEquation
Kelt1/2 = 0.69/ Kel
73
What is Cp shorthand for
Plasma concentration
74
Are Kel and half life dependant on the dose administered
No
75
What is clearance (Cl)
The volume of plasma cleared of drug per unit time (a constant relating the rate of elimination to plasma concentration)
76
What type of kinetics does clearance apply to?
First order
77
Rate of elimination =
Rate of elimination = Cl X Cp
78
Maintenance dose rate?
Dose per unit time required to maintain a given plasma concentration
79
At steady state (SS)
Rate of elimination
80
Cps.s.=
Cps.s. = maintenance dose rate / Cl
81
For drugs that exhibit first order kinetics, what is the steady state (SS) plasma concentration linearly related to
infusion rate
82
What is the time to reach Css determined by?
half life (NOT the infusion rate)
83
When is Css reached?
After approx. 5 half lives
84
What is bioavailability (F)
Fraction of drug administered that enters the systemic circulation?
85
Css(average) = (oral dose)
FXdose / Clp X dosage interval
86
Volume of distribution (Vd)
Volume into which a drug appears to be distributed with a concentration equal to that of plasma (relates plasma concentration (Cp) to the amount of drug in the body (Ab)
87
Ab = ?
Ab = Vd X Cp (C=mXV)
88
Loading dose (LD)?
An initial high dose of a drug given at the beginning of a course of treatment before stepping down to a lower maintenance dose
89
LD (for IV) =
LD (IV) = Vd X target Cp
90
LD (for oral) =
LD = Vd X target Cp / F
91
In terms of Vd and Cl, what does t1/2 =?
t1/2 = 0.693 X Vd / Cl
92
What happens during zero order kinetics?Example of 2 drugs that do this?
Drugs are initially eliminated at a constant rate, rather than at a rate proportional to their concentration (straight line on graph rather than curve)Ethanol and phenytoin
93
When do drugs exhibit zero order kinetics?
When Cp > km of an enzyme that metabolises it

1st Year - Principles (37 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions