Exam III: Things to memorize Flashcards
1
Q
Define absorption
A
the RATE and extent drug enters body
2
Q
define distribution
A
which tissues drug enters and HOW RAPIDLY that occurs
3
Q
define metabolism
A
which enzymes metabolize drug and HOW FAST drug is converted
4
Q
define excretion
A
route of excretion and HOW RAPIDLY drug leaves body
5
Q
define pharmacokinetics
A
study of ADME
6
Q
define clinical pharmacokinetics
A
the application of PK for patients
7
Q
define kinetic homogeneity
A
relationship between plasma drug concentration and concentration at the receptor site
8
Q
define pharmacodynamics
A
relationship between drug concentration at site of action and resulting effect (time and intensity)
9
Q
what are the four factors of pharmacodynamics?
A
- # of receptors
- mechanism of signal
- gene transcription
- protein production
10
Q
what is the abbreviated unit for defining the maximum effect?
A
Emax
11
Q
What is EC50?
A
describes when a drug is at 50% effective concentration
12
Q
the lower EC50 is, what does that mean about the drug?
A
the longer it takes a drug to reach 50% concentration the more potent the drug is
13
Q
what does chromatography do?
A
separates drugs from other materials
14
Q
what does mass spectrometry do?
A
detects molecules based on their mass-to-charge ratio
15
Q
what is the toxic dose of caffeine in grams?
A
10g
16
Q
how many mg of caffeine is in a cup of coffee?
A
80-175mg
17
Q
how many cups of coffee would it take to reach a lethal dose of caffeine?
A
50-100 cups
18
Q
what is the primary metabolite caffeine converts into?
A
paraxanthine
19
Q
what are the three main metabolites of caffeine?
A
paraxanthine, theobromine, theophylline
20
Q
what does MTC stand for?
A
maximum tolerated concentration
21
Q
what does MEC stand for?
A
minimum effective concentration
22
Q
what does tmax mean?
A
the duration of time it took for a drug to reach maximum concentration in plasma
23
Q
a drug must reach a minimum concentration at the receptor site to be _____
A
effective
24
Q
T/F For most drugs, there is no
absolute set of boundaries that
divide sub-therapeutic, therapeutic,
and toxic drug concentrations
A
True
25
define tolerance
a diminished response to drug over repeated use and body adaptation
26
T/F drug metabolism has no influence over drug tolerance
False
27
T/F changes in receptor status has no influence over drug tolerance
False
28
how does the body build up tolerance to nitroglycerin?
blood vessels become desensitized to vasodilation
29
what was the solution to nitroglycerin tolerance?
spaced dosing with patch : 12 hours on and 12 hours off
30
what is theophylline used to treat? what does it do?
COPD and asthma
| smooth muscle relaxation and suppression of response of airway to stimuli
31
what does TDM stand for? define it
therapeutic drug monitoring: methods for measuring drug conc in plasma
32
T/F TDM is useful for wide plasma concentration ranges
False
33
T/F TDM is useful when toxic effects can occur at high or low concentrations
False
34
what does the one-compartment model mean?
drug distribution to all body tissues are considered
35
what does two-compartment model mean?
drug distributes to selective body sites initially before distributing to an equilibrium
36
what are the steps in order for real world measurement of drug concentration?
1. Dose administered
2. Sample collected
3. Sample analyzed for drug/metabolites
4. Data analysis
37
what is the average human blood volume in liters?
5L
38
what was gentamicin initially used for?
topical burns
39
Gentamicin is a good treatment for?
sepsis
40
Is gentamicin heat stable?
yes
41
how do you determine the Volume of Distribution? units?
amount of drug in body (X measured by mg or g, etc.) divided by concentration of drug in plasma (C measured by mg/L)
units of Vd is liters
42
X=
amount of drug in body
43
VD=
volume of distribution
44
C=
concentration of drug in plasma
45
Volume of distribution only accounts for all of the drug in the body if?
the concentration in all tissues are the same as the plasma concentration
46
If Vd is 15-18L, where is the drug concentrated?
extracellular fluid
47
if Vd is 40L, where is the drug concentrated?
all body water
48
if Vd is greater than 40L, where is the drug concentrated?
tissues outside plasma and interstitial fluid
49
what is the relationship between dose and volume of distribution?
... the higher the dose?
the higher the dose is, the higher the volume of distribution will be
50
what is the relationship between concentration of drug and volume of distribution?
they are inversely related: the greater the drug concentration the lower volume of distribution will be
51
define clearance
measures the removal of drug from the body, aka the volume of plasma from which all drug is removed in a given time period
52
what does the unit Q represent?
blood flow (mL/min)
53
what does the unit E represent?
extraction ratio
54
in zero-order elimination how is the amount of drug eliminated determined?
amount of drug eliminated is a constant rate
| ex. 100g of drug given, 10g (10%) is eliminated every hour
55
in first-order elimination, the amount of drug eliminated is proportional to...
the amount of drug in body
56
equation of clearance? units?
Cl=VdK
| L/t
57
equation for elimination rate constant? what is the symbol?
K = change in ln concentration/ change in time
58
e^-Kt =
percent or fraction remaining after time
59
1-e^-Kt=
percent or fraction excreted after time
60
Both T1/2 and K express?
how quickly a drug is removed from the plasma
61
assumptions of multiple IV bolus dosing
1 drug at same dose given multiple times by IV
62
what is T?
dosing interval, time between administration of doses
63
Cmax2 is proportional/equal to?
Cmax1 + Cmin1
64
IV bolus steady state means the drug is administered until the rate of drug....
rate of drug going in = rate of drug going out
65
how many half lives does it take to reach steady state?
4-5
66
if K increases, how does that affect the time it takes to reach steady state? why?
takes a shorter amount of time the higher K is
since higher K = shorter half life, this means it takes less time to reach steady state since steady state is proportional to the time it takes for 4-5 half lives to occur
67
if a drug has a low K rate, is the half life longer or shorter?
longer (inversely proportional)
68
if you double the dose, how would this look on the [ ] vs time graph? (interval, rate, concentration, time between doses)
same interval, same rate, higher concentration, same time between doses
69
if you increase the frequency of dosing, how would this look on the [ ] vs time graph? (interval, rate, concentration, time)
decrease interval, increase rate, higher concentration, less time between doses
70
what does the accumulation factor relate?
drug concentration after a single dose to drug concentration after n doses
71
would you administer vancomycin orally?
no
72
what is vancomycin a first-line treatment for?
MRSA
73
what is average steady state concentration?
| what is the symbol?
the average concentration level between the maximum Cs and minimum Cs
c̅
74
if K decreases, how does this affect Cpeak at steady state and Ctrough at steady state?
they both become higher *remember lower K means drug is eliminating slower, so concentration will increase quicker with multiple doses)
75
if T decreases, how does this affect Cpeak at steady state and Ctrough at steady state? how does this affect K?
they both become higher. K stays the same
76
if X increases, how does this affect Cpeak at steady state and Ctrough at steady state? how does this affect K?
they both become higher. K stays the same
77
If Vd decreases (Xo, T, and Cl remain the same). how does this effect CpeakSS?
it increases (CpeakSS is inversely proportional to Vd)
78
If Cl decreases (Xo, T and Vd remain the same), how does this affect Cpeak at steady state and Ctrough at steady state?
they both become higher (Cl relates to Vd, lower Cl means lower Vd which is inversely related to Cpeak and Ctrough so they both increase)
79
how do you calculate ko?
mass/time (mg/hr)
80
what is ko?
| what is it equal to?
the rate of drug infusion
| Ko=X/t
81
For the equation Ct= Ko/VdK (1-e^-kt), is it used prior to steady state or after drug reaches steady state?
the same equation also determines what concentration?
calculate concentration before steady state
| peak concentration
82
what does Ct=Css(e^-kt) calculate?
plasma drug concentration after infusion stopped (after reaching steady state)
83
define loading dose
an initial higher dose of drug given at the start of infusion to create an immediate therapeutic effect of the drug (plasma drug concentration starts high and stays constant)
84
what is t' and how is is calculated?
time after peak concentration, t'= T-t
85
T/F Because we cannot practically measure drug concentration in specific tissues, we measure it in the plasma and assume that this concentration is the same as that in tissue.
False, we cannot assume the concentration is the same in tissue
86
T/F a drug must reach a minimum concentration at the receptor site to be effective
True
87
T/F more side effects occur when you give a drug below therapeutic range
False, above therapeutic range
88
T/F tolerance occurs when your body adapts to repeated drug use
True
89
T/F tolerance can be affected by drug metabolism and receptor status
True
90
```
The most commonly used model in clinical
pharmacokinetic situations is the:
A. One-compartment model
B. Two-compartment model
C.Multi-compartment model
```
A. One-compartment model
91
T/F your total body water makes up 60% of your total body weight
True
92
```
If the elimination rate constant is 0.2 hr-1 the
percent of drug eliminated per hour is:
A. 2%
B. 20%
C. 0.2%
D. 10%
```
B
93
To calculate how long it takes to reach steady state, you can multiply the half-life value by what to get the answer?
5
94
generally speaking, after 4-5 half lives the percent remaining drug plasma concentration is?
95%
