Pharmacokinetics - Exam 3

Question 1

definition of pharmacokinetics

Answer 1

the mathematical description of the plasma concentrations-time course

Question 2

dosage regimen

Answer 2

dosage, route of administration, frequency, duration of administration

Question 3

optimal dosage regimen

Answer 3

effective, nontoxic, without prolonged drug residues in the tissues of food animals

Question 4

systemic bioavailability

Answer 4

fraction of the dose which reaches the systemic circulation intact; F%, measures extent of absorption

Question 5

AUC

Answer 5

area under the curve;

Question 6

F% =

Answer 6

AUC extravascular / AUC IV x 100

Question 7

the concept of compartments

Answer 7

compartments refers to those tissues and organs for which the rates of uptake and subsequent clearance of are drug similar

Question 8

4 main compartments

Answer 8

blood, tissue, fat, 3rd spaces

Question 9

one compartment model

Answer 9

all tissues & organs which the drug penetrates behave as if they were in ready equilibrium with the blood, liner

Question 10

two compartment model

Answer 10

central and peripheral compartment; curved

Question 11

rate of distribution

Answer 11

estimated by the distribution phase half life in the 2 compartment model

Question 12

extent of distribution

Answer 12

measured by apparent volume of distribution (Vd)

Question 13

Vd is the

Answer 13

volume of distribution, volume of fluid, concentration in plasma in L/kg

Question 14

for IV administration, Vd=

Answer 14

dose/Cp

Question 15

for non-IV administration Vd=

Answer 15

dose * F% / Cp

Question 16

Vd < 1L/kg

Answer 16

limited distribution

Question 17

Vd = 1L/kg

Answer 17

wide distribution

Question 18

Vd > 1L/kg

Answer 18

very wide distribution

Question 19

example of small vd drug

Answer 19

heparin

Question 20

example of large vd drug

Answer 20

morphine

Question 21

elimination

Answer 21

drug elimination is measured by 1/2 life or total body clearance (CLb)

Question 22

half life

Answer 22

t 1/2; time required for the body to eliminate one half of the drug it contains, independent of dose given & route of administration

Question 23

elimination of most drugs follows

Answer 23

first order kinetics

Question 24

first order kinetics

Answer 24

means the rate of removal of the drug from the plasma is proportional to the concentration present at a given time, constant percentage, curved

Question 25

constant percentage

Answer 25

of drug is eliminated per unit time

Question 26

zero order kinetics

Answer 26

means the rate of elimination remains constant regardless of the amount of drug in the body, constant amount, straight line

Question 27

after how many half lives is the drug almost all the way excreted

Answer 27

5th

Question 28

steady state

Answer 28

rate at which plasma concentration of a drug rises to reach a steady state concentration

Question 29

Cp(ss) is the

Answer 29

steady state [plasma], maintenance rate of drug administration is equal to the rate of elimination

Question 30

Cp(ss) achieved when

Answer 30

CRI maintenance = rate of elimination

Question 31

a faster rate does not achieve cpss any faster, only

Answer 31

increase dose does this

Question 32

plasma clearance (CLp)

Answer 32

volume of plasma cleared of the drug per unit time

Question 33

renal clearance (CLr)

Answer 33

volume of the plasma cleared of the drug by the kidneys per unit time

Question 34

CLp equation =

Answer 34

rate of elimination (ml/min)/ plasma drug concentration (mg/ml)

Question 35

total body clearance CLb

Answer 35

rate of drug elimination from the body by all routes, relative to the concentration of the drug in plasma

Question 36

increased Vd results in

Answer 36

decreased clearance

Question 37

increased half life results in

Answer 37

decreased clearance

Question 38

CLb =

Answer 38

Vd x 0.693 / t 1/2

Question 39

t 1/2 =

Answer 39

0.693 x Vd / CLb

Question 40

Cl organ =

Answer 40

Q (blood flow to organ) x E (extraction ratio)

Question 41

examples of drugs with high hepatic extraction ratio

Answer 41

lidocaine & diazepam

Question 42

T/F: high first pass effect = high extraction ratio

Answer 42

true

Question 43

maintenance dose:

Answer 43

dosing rate = CLb x Cp(ss)

Question 44

loading dose

Answer 44

Vd x desired Cp

Question 45

if renal disease (insufficiency) present, this will cause ______ in excretion

Answer 45

decrease

Question 46

change dose or dose interval will help prevent

Answer 46

accumulation

Question 47

adjusted dose calculation

Answer 47

normal dose x (patient renal clearance / normal renal clearance) smaller

Question 48

adjusted dose interval calculation

Answer 48

Dose x F% / CLb x Cp(ss) larger

Question 49

renal clearance estimated by

Answer 49

creatinine clearance

Question 50

rate of elimination equation

Answer 50

mg/min; urine flow (ml/min) x [drug] in urine (mg/ml)