Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

FOM 3 wks 7-9 > quantitative pharmacokinetics > Flashcards

quantitative pharmacokinetics Flashcards

1
Q

characteristics of a Compartment

A

-NOT a real anatomical region
-group of tissues w similar blood flow / drug affinity
-an open system (bc the drug can be eliminated from it)
-rapid mixing
-uniform distribution of drug within space

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

within a Compartment, the drug is _____ & _____

A

-uniformly distributed
-mixed rapidly & homogenously

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

what do rate constants represent in a Compartment

A

drug entry / exit from Compartment

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

what is 1CM

A

1-compartment model

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

what is 2CM

A

2-compartment model

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

factors of a 1CM

A

-single well-mixed container
-drug in blood is in rapid equilibrium w drug in extravascular tissues
-rapid mixing
-linear model- first order elimination

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

factors of a 2CM

A

-NO instantaneous distribution of drug within body
-has peripheral compartment

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

central compartment is comprised of _____

A

the vascular system (highly perfused tissues)

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

peripheral compartment is comprised of _____

A

poorly perfused tissues

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

the drug distributes to the peripheral compartment based on _____

A

the rate of transfer from the central compartment

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

what is zero-order kinetics

& example of drug(s)

A

a constant amount of drug is absorbed / eliminated per unit time

ethanol

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

what is an example of a zero-order process

A

a constant rate IV infusion

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

what is first-order kinetics

& example of drug(s)

A

a fraction of drug is absorbed / eliminated per unit time

most drugs

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

what is mixed-order kinetics

A

at low drug concentrations = first-order (dose-dependent)

at high drug concentrations = zero-order (dose-independent)

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

zero-order kinetics is dose-_____

A

independent

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

first-order kinetics is dose-_____

A

dependent

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

2 examples of drugs w mixed-order kinetics

A

phenytoin
&
salicylic acid (active metabolite of aspirin)

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

rate of change of amount of drug in the body is independent of _____

A

the quantity/concentration of drug in the body

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

why does drug concentration increase during the absorptive phase

A

bc rate of absorption is greater than rate of distribution / elimination

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

what happens at Cmax (drug concentration max)

A

rate of absorption falls

rate of distribution & elimination rises

-> and rate of absorption becomes = rate of elimination

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

what is peak concentration

A

the point where rate of absorption = rate of elimination

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

what is happening at stage 4 on the graph

A

there is a negative net balance & blood levels decline (bc very little drug is still available at the absorption site)

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

drug levels that fall into therapeutic window are considered _____

A

pharmacologically effective

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

what is true for drugs that fall in upper threshold of therapeutic window

A

they produce more side effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what is the "duration of effect"
the time during which the drug concentration lies within the therapeutic window
26
what is true of the AUC (area under the curve) on the plasma-drug concentration time curve
AUC = the actual body exposure to the drug (mg/L x hr)
27
AUC is dependent on _____ AND _____
rate of elimination of drug from body dose administered
28
AUC is directly proportional to _____ when _____
the dose, when drug follows linear kinetics
29
AUC is inversely proportional to _____
clearance of the drug
30
what is the elimination rate constant (k e)
a constant that links "rate of elimination" to available mass of drug in the body
31
equation for rate of elimination
rate of elim = mass x (k e) mass: of drug in body
32
2 equations to find elim rate constant (k e)
(k e) = rate of elim / mass (k e) = drug clearance / Vd Vd: apparent volume of distribution
33
elim rate constant (k e) is a _____ per drug per patient
fixed value
34
what is the half life of a drug
the time it takes for plasma concentration of drug to decrease by 50% (same amount of time per interval, and same fraction (50%) of drug eliminated, but amount of drug eliminated decreases)
35
half life equation
half life = 0.693 / (k e)
36
equation for "apparent volume of distribution" (Vd)
Vd = dose / Cp Cp: drug concentration in blood
37
equation to find dose from blood concentration of drug
dose = Vd x Cp Vd: apparent volume of distribution Cp: drug concentration in blood
38
what shortens half life
decreased volume of distribution increased clearance
39
what lengthens half life
increased volume of distribution decreased clearance strong plasma protein binding
40
what does not affect half life
dose administered
41
why do (oral dose) drug concentrations reach Cmax
(to get to Cmax) rate of absorption > rate of elimination (at Cmax) rate of absorption = rate of elimination
42
what is steady state (in continuous IV infusion)
when rate of drug entry into the body is balanced by rate of elimination & no further drug accumulation occurs
43
equation that relates (R inf) and (C ss), and what is this equation independent of
(C ss) = (R inf) / clearance (C ss): [drug] at steady state (R inf): rate of infusion *independent of # of compartments
44
why should an IV infusion have a loading dose
bc drugs w longer half-lives take longer to reach steady state -> loading dose brings drug to therapeutic window quicker
45
what is a loading dose
an extra dose
46
equation for loading dose (drug has no absorption component)
loading dose = target Cp x Vd target Cp: desired [plasma] Vd: volume of distribution
47
bioavailability (F) of drug given by IV
= 1.0
48
equation for loading dose (drug HAS absorption component)
loading dose = target Cp x Vd/F target Cp: desired [plasma] Vd: volume of distribution F: bioavailability
49
a drug w short half-life will reach Css _____ vs a drug w long half-life
quicker
50
as long as system is linear, increasing dose will _____ AUC
increase AUC
51
absolute oral bioavailability equation
absolute oral bioavailability = AUC oral / AUC iv
52
what is absolute bioavailability
the bioavailability when extravascular route is compared to IV route
53
what is relative bioavailability
% of test dosage that becomes bioavailable compared to reference dosage
54
what can relative bioavailability NOT tell you
how much drug test dosage delivers systemically (can only be determined when test dosage is compared to IV dose)
55
relative bioavailability for capsule equation (tablet vs capsule)
relative bioavailability for capsule (relative to tablet) = AUC capsule / AUC tablet
56
how many half-lives does it take to reach 93.8% of the target concentration
4
57
what is pharmacokinetic accumulation
during multi-dose regimen, when a drug has SLOW rate of elimination
58
equation for avg Css (concentration of drug at steady state)
Css avg = (F x D) / (Cl x t) F: bioavailability D: dose Cl: clearance t: dosing interval independent of compartment #
59
Css avg units
mg/ml
60
time to reach steady state depends ONLY on _____
half-life
61
t (dose interval) if drug is given twice daily
12 hrs
62
t (dose interval) if drug is given 4x daily
6 hrs
63
increasing dosing rate will ONLY increase _____
avg steady state concentrations (does NOT shorten time taken to get to steady state)
64
in first-order kinetics, the rate of elimination (ROE) is directly proportional to _____
mass of the drug
65
which drugs should have a loading dose
drugs with the longest half-life
66
loading dose only changes _____, it does NOT change _____
changes time to get to therapeutic window does NOT change time to get to steady state
67
the only factor that determines time to reach steady state
half-life

FOM 3 wks 7-9 (24 decks)

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