Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Phase I Medicine > Pharmokinetics > Flashcards

Pharmokinetics Flashcards

1
Q

What is pharmacology?

A

Branch of medicine and biolgy concerned with the study of drug action.Interactions that occur between a living organisms that affect normal/abnormal biochemical function

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

What is a drug?

A

Any man-made, natural or endogenous molecule that exerts a biochemical/ physiological effect on a cell/tissue/organ/organism

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

What does endogenous mean?

A

(Made) within the body

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

What do drugs usually act on?

A

Target proteins

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

What is a receptor?

A

Protein molecules whose function is to recognise and respond to endogenous chemical signals

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

What is the difference between a receptor and a drug target

A

Receptor - recognise and respond to chemical signals

Drug target -other macromolecules that drugs interact with to produce their effects

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

What is the importance of pinpointing the receptor locations?

A

Allows drugs to target specific tissues

Allows predictions of side effects (if the receptors are found in other parts of the body too)

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

How much does the chemical nature of the drug have to match that of the target molecule?

A

Almost perfectly

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

Drug-receptor interactions are dynamic. What does this mean?

A

Drugs bond to the receptor molecules (non-covalently) to form the active form of the complex. After this itcan dissociate for the cycle to repeat itself.

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

What is the definition of specificity?

A

How many receptors can the drug bind to and how many drugs can the receptor molecules bind? The greater the number, the lower the specificity.

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

What is the definition of affinity?

A

How strong is the (non-covalent) bonding between the drug and the receptor molecule?

Measured by the dissociation constant of the DR complex.

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

What is the definition of the dissociation constant?

A

The concentration at which half the drug is bound to the receptor at equilibrium.

Like rate constant/ half-life

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

what is the name of the law thatstates that the rate of a chemical reaction is proportional to the product of themassesof the reactants?

A

Law of mass action

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

If all the receptors for the drug are bound, will increasng dosage increate the rate of binding?

A

No - No additional positive effects

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

If the drug is able to bind to other receptor molecules, what effect would this have on the free solution?

A

Concentration of drug in free solution decreases

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

What is an agonist?

A

Drug that produces a positive effect when bound to a receptor

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

What is an antagonist?

A

Drug that reduces the effect of an agonist at a given receptor

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

What is an inverse agonist?

A

A drug that produces a negative effect when bound to a receptor.

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

What is efficacy (Emax)?

A

The maximum response achievable from a drug

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

What is potency?

A

The dose of a drug required to produce a specific effect of given intensity

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

What 2 things does the potency of a drug depend on?

A

Efficacy and affinity

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

True or false? The rate that a drug binds to receptor molecules can be linked to the activity that we can see (response)

A

True - Response/ Effect equation

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

How can the concentration of the agonist bound to the receptor be displaced?

A

An artificially introduced antagonistCompetitive antagonism

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

What is non-competitive antagonism?

A

Where an antagonist may not bind to the same part of the target siteAnon-competitive antagonistbinds to an allosteric (non-agonist) site on the receptor -prevents activation of the receptor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is inverse agonism?
An agent (inverse agonist) binds to the same receptor as an agonist but induces an opposite response to that of the agonist.
26
What is the difference between an antagonist and an agonist?
Antagonist usually blocks the receptor thus reducing the effect of the agonistInverse agonists do result in an effect but it'sthe opposite to the agonist
27
True or false? You can antagonise inverse agonism just as much as normal agonism?
True
28
What type of receptor is responsible for the largest number of prescriptions given out in the UK?
Nuclear receptors
29
What is the most important thing to remember when thinking about drug targets?
The type of receptor and effector system
30
What is the structure of nuclear receptors?
Monomeric; separate receptor and DNA-binding domains
31
What is the effector and coupling for nuclear receptors?
Gene transcriptionCoupling via DNA
32
Give a positive and negative or inverse agonists
+ They have less of an effect in comparision to normal agonists- The receptor is actually doing something as a result of their binding (negative effect)
33
What is pharmokinetics?
Factors that determine the active concentration of the drug at the active site
34
What is absorbtion?
The mechanism of accumulation of the drug in a body compartment following administration
35
What is distribution?
The way in which a drug reaches each organ of the bodyDrugs get 'all over the place' in varying degrees
36
What is metabolism?
The chemical alteration of a drug into (ultimately) its inactive formsThe body will get rid of the foreign stuff
37
What is excretion?
Removal of the drug and/or its metabolites from the body
38
What is the importance of plasma in pharmacology?
A key measurement of how much drug is active in the patient's systemThe least invasive way to get a good measurement
39
Where is the main site of metabolism?
The liver
40
What is the difference between ionised and unionised drugs in terms of absorption?
Ionised - Will not pass through membrane unless there's a specific transport molecule Unionised - Will pass through lipid membrane (speed/ ease dependent on lipophilicity)
41
What is the relationship between pH and pKa for drug ionisation?
Drugs will be ionised when pH is opposite to pKa 
42
What proteins do drugs bind to?
Plasma/ tissue proteins
43
What is 'volume of distribution'?
Theoretical volume that the total amount of administrated drug would have to occupy (if it were uniformly distributed), to provide the same concentration as is in blood plasma.
44
What does liver metabolism usually do to drugs?
Inactivates drugs Metabolites may remain active Even before the substance accumulates, the liver is trying to get rid of it
45
What is a prodrug?
An inactive/ weakly active substance that has an active metabolite
46
How can the liver metabolise drugs?
``` Oxidation Reduction Hydrolysis Hydration Conjugation CondensationIsomerization ```
47
What are the 3 main mechanistic processes that allow the kidneys to regulate the chemical constituents in the blood?
Glomerular filtration Tubular Secretion Tubular Resorption
48
What is Cp?
Drug concentration in plasma; assumed to relate to extracellular fluid surrounding cells
49
What is Cmax?
Maximum plasma concentration following a given dose
50
What is Tmax?
The time between drug dose and achieving Cmax
51
What is used to adjust dosing regimen, based on experimental estimates and patient data.
Parameters
52
What is Kabs?
A rate constant which governs the transfer of the drug to its central compartment 
53
Kabs is assumed to be directly proportional to what?
The amount of drug that is still unabsorbed
54
What happens as a result of slow absorption?
Cmax is reduced | Duration of action is increased
55
What happens to Cp once absorption is complete?
It declines with the same t1/2 | This happens irrespective of the rate of absorption
56
What is important to note about the description of Vd?
It is an apparent volume rather than a specific anatomical compartment
57
What is C0?
Initial concentration
58
What is the term used to describe the time taken for Cp to fall by 50%?
Elimination half-life
59
What is a 'loading dose'?
A dose of medication, often larger than subsequent doses, administered for the purpose of establishing a therapeutic level of the medication.
60
What are the limitations of the single compartment model?
* Over simplification * Assumes rate of absorption, metabolism and excretion are directly proportional to drug concentration in the compartment. * Different tissue compartments may affect time courses of drug distribution
61
What is the difference between the single-compartment model and the two-compartment model?
Two-compartment model has a peripheral compartment represented by tissues Drugs enter second compartment via central (plasma) compartment An extra exponential component is added to the Cp time course
62
Double exponential kinetics features two phases. What are they?
``` Fast phase (alpha) Slow phase (ß) ```
63
What is the fast phase of the Cp time course?
Represents transfer between central and peripheral compartments (plasma-> tissues)
64
What is the main limitation of double exponential kinetics?
Some drugs are not equally soluble across all tissues
65
What is saturation kinetics?
Alternative explanation for elimination from plasma - disappearance is linear, irrespective of dose or Cp
66
What are the implications of saturation kinetics?
Duration of action is more depedent on dose - the first probably saturated the enzymes involved Relationship between dose and steady state Cp is steep and unpredictable - more likely to experience side effects because it is easy to pass the therapeutic window Drugs with these kinetics are difficult to administer effectively so may be rejected in development
67
What are the cytochrome P450 enzymes?
Haem proteins, 3 of which are involved in drug metabolism Differ from one another and in the specificity of the reactions they catalyze Induced/ inhibited by many substances resulting in drug interactions- one drug enhances the toxicity or reduces the therapeutic effect of another drug.
68
What is irreversible binding?
An antagonist binding covalently to the receptor and cannot be displaced by competing ligands or washing.

Phase I Medicine (46 decks)

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