Introduction to pharmacokitentics 2

Question 1

2 main kinetic properties of drugs

Answer 1

first order

zero order

Question 2

first order drugs

Answer 2

rate of elimination proportional to Cp
percentage of the total amount of the Cp change remains constant over time
its blood level drops the same percentage every time interval–even though the amount lost is smaller each time

Question 3

zero order drugs

Answer 3

saturable (max) can’t metabolize after a certain amount
percentage of total amount of the Cp change is not constant
lose the same amount each time interval–not the same percentage

Question 4

onset?

Answer 4

time it takes to get the MEC (minimal effective conc)

IV-onset of activity is shorter–hits MEC faster

Question 5

TMax?

Answer 5

time it takes to get to Cmax

Question 6

duration of action?

Answer 6

where drug is effective (MEC to MEC)

Question 7

CMax?

Answer 7

highest conc of drug in blood–no more absorption

peak

Question 8

Cmin?

Answer 8

lowest concentration of drug in patient that occurs before the next dose is given
dosing interval is 1 of key things that indicates Cmin

Question 9

MEC

Answer 9

minimal effective conc

lowest plasma conc that becomes effective

Question 10

MTC

Answer 10

maximal therapeutic conc

if above–toxicity occurs

Question 11

therapeutic range

Answer 11

between MEC (minimal effective conc) and MTC (maximum therapeutic conc)

Question 12

F

Answer 12

bioavailability
Fraction of a dose that enters circulation
extent of absorption
F=1 for IV route
no units

Question 13

determines bioavailability

Answer 13

ionization status, first pass, dissolution

F=AUCoral/AUCivx100

Question 14

S

Answer 14

salt factor
represents percentage of a dose that equals primary serum assessed drug
no units

Question 15

3 items determining amount of drug absorbed

Answer 15

dose, bioavailability (F) and salt factor (S)

Question 16

Vd

Answer 16

volume of distribution–units is L
volume of compartment necessary to account for total amount of drug in body and drug conc in plasma
not a physiologic value
represents extent of drug distribution

Question 17

bigger value of Vd means what?

Answer 17

larger body distribution the more places the drug goes to/goes out of bloodstreams
blood volume in our body is 5 L

Question 18

IBW

Answer 18

ideal body weight–units–kg
female=45kg +(2.3kgx inches above 60 inch)
Male=50 kg + (2.3 kg (height over 60 inch)

Question 19

Adj body weight

Answer 19

adjusted dosing body weight–for actual BW>40% than IBW

Adj BW= 0.4x (ABW-IBW)+IBW

Question 20

Cl–what is it? units?

Answer 20

units is L/hr
have to multiply its weight to book value
volume of blood per unit of time that is cleared of drug

Question 21

Tau

Answer 21

units=hrs
represents dosing interval
if q8h then tau=8

Question 22

Kel

Answer 22

elimination rate constant–units–x^hrs
a function of clearance
percentage of drug removed per unit of time

Question 23

T1/2

Answer 23

half-life–units is hrs

time required for 50% of drug to be eliminated (blood conc to lower by 50%)

Question 24

Cpss

Answer 24

steady state–units w/v
equilibrium between drug and body where Rate in=Rate out
time dependent

Question 25

how long for pts to develop steady state?

Answer 25

4-5 half lives of the drug

Question 26

At CPss what occurs?

Answer 26

DD/DL

if double the dose at steady state, you double the level of blood

Question 27

Amount of drug absorbed formula

Answer 27

(S)(F)(Dose)

Question 28

Loading dose

Answer 28

(Vd)(Cpdesired)/(S)(F)

Question 29

Supplemental Loading dose

Answer 29

(Vd)(Cpdesired-Cpinitial)/(S)(F)

Question 30

Clearance (Cl)

Answer 30

(S)(F)(Dose/Tau)/(Cp)

Question 31

Maintenance Dose

Answer 31

(Cl)(Cp)(Tau)/(S)(F)

Question 32

Elimination rate constant (Kel)

Answer 32

(Cl)/(Vd)

Question 33

Half life (t1/2)

Answer 33

0.693/(Kel)

Question 34

Creatinine Clearance (eGFR)

Answer 34

[(140-age)XIBW (in kgs)]/(72xSCr)

x0.85 if pt is female

Question 35

Dose of diff dosage Form=

Answer 35

Amt (mg) Absorbed for current form/[(S)(F) of New Dosage form)]

Question 36

Concentration in plasma (Cp)=

Answer 36

(S)(F)(Dose)/Vd