7343 PK Test 3 Flashcards
(141 cards)
1
Q
antiarrythmics metabolized by what CYP?
A
2D6
2
Q
fluoxetine and paroxetine metabolized by what CYP?
A
2D6
3
Q
antipsychotics metabolized by what CYP?
A
2D6
4
Q
metoprolol and carvedilol metabolized by what CYP?
A
2D6
not atenolol
5
Q
codeine and tramadol metabolized by what CYP?
A
2D6
6
Q
CYP2D6 metabolizes what % of drugs?
A
25-30
7
Q
2D6 poor metabolizer genotype?
A
4/4 or 4/6
5-10% of whites
1% of asians
8
Q
What % of whites are 2D6 UMs?
A
5%
9
Q
duplication of gene metabolizer?
A
UM
10
Q
2D6 PM have what symptoms with antipsychotics?
A
extrapyridimal
11
Q
CYP2C9 poor metabolizer genotype?
A
- 2, *3 in whites
* 5 only in blacks
12
Q
What gene is key factor explaining dose variability of warfarin?
A
VKORC1
13
Q
phenytoin is metabolized by what CYP?
A
2C9
14
Q
warfarin is metabolized by what CYP?
A
2C9
15
Q
NSAIDS (ibuprofen, diclofenac) are metabolized by what CYP?
A
2C9
16
Q
ARBs are metabolized by what CYP?
A
2C9
17
Q
glipizide, glyburide metabolized by what CYP?
A
2C9
18
Q
CYP2C19 UM genotype?
A
*17
25% of whites
19
Q
CYP2C19 PM genotype?
A
*2, *3
1-3% whites
13-23% asians
20
Q
clopidogrel metabolized by what CYP?
A
2C19
prodrug
21
Q
PPIs metabolized by what CYP?
A
2C19
22
Q
diazepam is metabolized by what CYP?
A
2C19
23
Q
citalopram, escitalopram metabolized by what CYP?
A
2C19
24
Q
cyclophosphamide metabolized by what CYP?
A
2C19
25
bupropion metabolized by what CYP?
2B6
26
efavirenz metabolized by what CYP?
2B6
27
nevirapine metabolized by what CYP?
2B6
28
propofol metabolized by what CYP?
2B6
29
methadone metabolized by what CYP?
2B6
30
CYP2B6 PM genotype?
*6, *16
31
Which has higher conc. of nevirapine/efavirenz?
516GG or 516TT
516TT
PM genotype
32
CYP3A4 PM genotype?
*22
33
CYP3A4 UM genotype?
*1B, Por*28
34
CYP3A5 wild type genotype?
*1/*1 (normal expression)
80% african American
highest activity, highest dose requirement
35
CYP3A5 PM genotype?
*3/*3
85% whites
lowest activity, lowest dose requirement
36
caffeine, theophylline metabolized by what CYP?
1A2
37
clozapine, olanzapine metabolized by what CYP?
1A2
38
heterocyclic amines metabolized by what CYP?
1A2
39
What CYP is inducible by smoking 1PPD?
CYP1A2
40
What genes code for P-gp?
ABCB1, MDR1
41
What P-gp SNP is a silent mutation?
C3435T
TT less active (impaired efflux)
42
P-gp:
3435TT
more or less drug gets into blood?
more
43
P-gp:
3435CC or 3435CT
more or less drug gets into blood?
less
44
What CYP2C19 genotype is UM?
*17
white 25%
45
What CYP3A4 genotype is UM?
*1B, Por*28
46
What CYP3A5 genotype is UM?
*1/*1
80% african American
47
What CYP2D6 genotype is UM?
duplication of gene
white 5%
48
How is fosphenytoin dosed?
phenytoin sodium equivalents (PE)
1PE = 1mg phenytoin sodium = 1.5mg fosphenytoin sodium
49
Which dosage forms of phenytoin have salt factor (S) of 0.92?
capsules and injection
50
Which dosage forms of phenytoin have salt factor (S) of 1?
suspension and chewable tabs
51
Is phenytoin highly protein bound?
yes
90%
52
What CYPs metabolize phenytoin?
2C9 and 2C19
95% hepatic
53
Non-Linear PK of phenytoin:
enzyme induction has what effect on Vmax?
increased Vmax
54
Non-linear PK of phenytoin:
hepatic cirrhosis has what effect on Vmax?
decreased Vmax
55
Non-linear PK of phenytoin:
competitive inhibition has what effect on KM?
increased Km
56
Non-linear PK of phenytoin:
decreased plasma protein binding has what effect on Km?
decreased Km
57
Do children have different Vmax and Km than adults for phenytoin?
yes
58
What is phenytoin adult Vmax and Km?
Vmax: 7 mg/kg/day
Km: 4mg/L
59
Which is relatively water insoluble?
phenytoin or fosphenytoin?
phenytoin
fosphenytoin water soluble
60
Phenytoin IV injections should not exceed what rate?
50mg/min
risk of hypotension
61
fosphenytoin max IV infusion rate is what?
150mg PE/min
100mg PE fosphenytoin = 100mg phenytoin sodium
62
Which has more rapid absorption?
phenytoin capsules or tabs
tabs
multiple doses/day required
capsules extended release
63
What is bioavailability of oral phenytoin?
100%
64
Phenytoin loading dose?
15-20mg/kg
1000mg/day
65
phenytoin maintenance dose?
children: 5-10mg/kg/day
adults: 4-6mg/kg/day (300-400max/day)
older adults: 200 mg/day max
66
What is the "magic" dose for phenytoin?
there is no magic dose
67
nystagmus occurs with what phenytoin conc.?
> 20ug/mL
68
ataxia occurs with what phenytoin conc.?
> 30ug/mL
69
seizures occur with what phenytoin conc.?
> 50-60ug/mL
70
phenytoin therapeutic range (total con.)?
10-20ug/mL
71
phenytoin unbound therapeutic range?
1-2ug/mL
72
Low albumin causes of increased unbound phenytoin:
```
liver disease
pregnancy
burns
trauma
malnourishment
```
can cause unbound phenytoin to be as high as 30-40%
73
endogenous compound displacement causes of increased unbound phenytoin:
hyperbilirubinemia
jaundice
liver disease
can cause unbound phenytoin to be as high as 30-40%
74
exogenous compound displacement causes of increased unbound phenytoin?
warfarin
valproic acid
aspirin (over 2g/day)
NSAIDs
can cause unbound fraction to be as high as 30-40%
75
Units of phenytoin loading dose?
mg
76
Units of phenytoin maintenance dose?
mg/day
77
warfarin inhibits what two natural anticoagulants?
proteins C and S
also inhibits activation of coagulation factors VII, IX, X, II
78
S-warfarin is metabolized by what CYP?
2C9
79
R-warfarin is metabolized by what CYP?
3A4, 2C19
80
What % of warfarin is protein bound?
99%
81
Which clotting factor has longest half-life?
II
60 hours
82
When is peak effect of warfarin reached?
72-96hrs (3-4 days)
83
Why does antibiotic use with warfarin cause increased bleeding risk?
gut flora produce vitamin K2. When these bacteria are killed there is less K2 production. Since warfarin inhibits activation of vit. K, the less there is present, the more effective warfarin is
84
grapefruit
increase or decrease warfarin effect?
increase
"F's and G's" increase
fish oil, ginkgo, fenugreek, garlic, grapefruit
85
St. John's wort
increase or decrease warfarin effect?
decrease
CYP inducers decrease:
St. John's wort
smoking
vitamin K
86
affects warfarin sensitivity?
2C9 or VKORC1?
VKORC1
more prevalent in asians
87
What CYP inducing antibiotic decreases warfarin effect?
rifampin
other CYP inducers that decrease:
barbiturates, carbamazepine, phenytoin
88
barbiturates
increase or decrease warfarin effect?
decrease
89
carbamazepine
increase or decrease warfarin effect?
decrease
90
phenytoin
increase or decrease warfarin effect?
decrease
91
SMX/TMP
increase or decrease warfarin effect?
increase
92
metronidazole
increase or decrease warfarin effect?
increase
93
fluoroquinolones
increase or decrease warfarin effect?
increase
94
azole antifungals
increase or decrease warfarin effect?
increase
95
amiodarone
increase or decrease warfarin effect?
increase
96
levothyroxine
increase or decrease warfarin effect?
increase
97
steroids
increase or decrease warfarin effect?
increase
98
fenofibrate/gemfibrozil
increase or decrease warfarin effect?
increase
99
warfarin:
INR goal for mechanical mitral valve?
2.5-3.5
2-3 for VTE TX and prevention, and bioprosthetic valves, aortic valves
100
What is a standardized prothrombin time that represents what you'd expect from a healthy adult pt?
international normalized ratio (INR)
higher than 1 = bleeding risk
lower than 1 = clotting risk
101
How often is warfarin monitored if pt stable for 6+ months?
q 8-12 weeks
102
How often is warfarin monitored initially?
q 2-3 days until INR achieved
then q 1-2 weeks until INR achieved x 2, then q 4 weeks until INR stable for 2 readings
103
Do you give vitamin K if pts's INR is <10 and they aren't bleeding?
no
104
anticoagulant reversal:
contains clotting factors, protein C and S, and heparin
PCC (Kcentra)
105
anticoagulant reversal:
promotes synthesis of clotting factors?
vitamin K
do not use IM (causes hematoma)
106
What do you give if warfarin pt has INR 10+ with major bleeding?
PCC
with or without vitamin K
107
aminoglycoside BBW for?
ototoxicity
nephrotoxicity
pregnancy
108
What is aminoglycoside spectrum?
gram (-) only
can be used for synergy against gram (+)
109
are aminoglycosides bactericidal or bacteriostatic?
bactericidal
110
are aminoglycosides concentration or dose dependent?
concentration
peak:MIC
111
AG extended interval optimizes ___ dependent killing.
concentration
higher doses with more time in between
reduces toxicity by using PAE
uses nomogram to determine intervals
112
AG synergy uses what kind of dosing?
weight based
1mg/kg IV q8h
gentamicin trough < 2
max 3mg/kg/day
113
What kind of dosing is used for plazomicin?
extended interval
114
What is preferred AG dosing strategy?
extended interval
Unless:
pregnant, ascites, or other fluid abnormality, changing renal fxn, CrCl < 20, or hemodialysis
115
Extended interval dose for tobramycin/gentamicin?
7mg/kg
116
Extended interval dose for amikacin?
15mg/kg
don't forget to divide amikacin level by 2 to plot on nomogram!!
117
infusion time for plazomicin?
30mins
other Ads 1hr
118
population data for AG Vd calculation?
0.25-0.35L/kg
119
population data for AG Ke calculation?
0.00293(CrCl) + 0.014
120
Cap CrCl at what # for AG calculations?
120ml/min
121
What weight is used for vanc dosing?
TBW
122
What parameter determines effectiveness of vanc?
bioavailability
AUC:MIC
123
What is goal AUC24 for vanc?
400-600 with MIC of 1
124
AEs of vanc?
red man syndrome
nephrotoxicity
ototoxicity
125
What Vd is used for vanc dosing?
0.7-0.8L/kg
126
MSSA bacteria developed what mutation to become MRSA?
MecA
127
Vanc population PK loading dose?
20-35mg/kg
| TBW
128
VAnc population PK maintenance dose?
15-20mg/kg
q8-12hrs
TBW
129
Vanc population PK Ke calculation?
0.00083(CrCl) + 0.0044
130
Bayesian modeling Vanc monitoring:
Collect how many levels after 1st and 2nd dose?
2
131
2 level PK approximation Vanc monitoring:
Collect how many levels after 4th dose?
2
don't forget to add up AUCs to tao 24 hrs in calculation
132
indications for hemodialysis in ESRD pts: AEIOU
```
acidemia
electrolyte abnormalities
intoxication (methanol, lithium, aspirin)
overload
uremia
```
133
Are SCr and BUN reliable in hemodialysis?
no
accumulate in dysfunction
134
what is sieving coefficient ?
how well drug is dialyzed
```
0 = does not cross
1 = freely crosses
```
135
Vanc in renal replacement therapy, focus on what?
pre-dialysis serum conc.
136
What is goal vanc. conc. in RRT?
15-20mg/L
137
When to take vanc level with RRT?
day of dialysis prior to HD
138
What is max dose of vanc in RRT?
3g
use TBW
139
Administer vanc before or after HD?
after
140
AG in RRT:
re-dose when level is less than 1?
pulse dosing
141
Use what weight for AG RRT?
ABW, IBW, TBW
IBW
traditional dosing only
