pharmacokinetics

Question 1

pharmacokinectics

Answer 1

quantitative expression of relationship between absorption, distribution and elimination of drugs as a function of time

Question 2

the effect of the drug is related to what

Answer 2

blood [drug]

Question 3

One compartment model

Answer 3

drug rapidly equilibrates between plasma and tissue relative to elimination rate

Question 4

semi-log plot of [plasma] over time, describe graph when drug follows first order kinetics for one-compartment model

Answer 4

straight line with

Question 5

changes in [plasma] reflects proportional change in concentration of drug where

Answer 5

tissue

Question 6

does drug distribute to all tissues

Answer 6

no

Question 7

how long does it take for drug to equilibriate in 2-compartment model

Answer 7

longer

Question 8

what are the two compartments in the model

Answer 8

central and peripheral

Question 9

in 2 compartment model, where does elimination occur

Answer 9

central compartment.

Question 10

what are the 2 phases in semi-log plot when drug follows first order kinetics for 2 compartment model

Answer 10

initial distribution

elimination phase

Question 11

definition of elimination kinetics first order

Answer 11

rate of decrease in [drug] is directly proportional to the amount of drug in body

Question 12

elimination kinetics first order, what fraction of the drug is eliminated

Answer 12

constant

Question 13

most drugs follow what order of kinetics

Answer 13

first

Question 14

define elimination rate constant (ke)

Answer 14

fraction of drug removed at any given time is constant and independent of dose

Question 15

semi-plot for one compartment first order kinetics will look like

Answer 15

straight linear line

Question 16

define zero order for elimination kinetics

Answer 16

constant amount of drug eliminated independent of dose

Question 17

describe the enzymes involved in zero order elimination kinetics

Answer 17

saturated

Question 18

define bioavailability

Answer 18

fraction of unchanged drug reaching systemic circulation after drug administration

Question 19

drugs administered by intravenous route have a bioavailability of what

Answer 19

1

Question 20

all other routes besides IV of administration have a bioavailability of

Answer 20

less than or equal to 1

Question 21

what letter represents bioavailability

Answer 21

F

Question 22

how is bioavailability determined after IV or other administration

Answer 22

measure [plasma] as function of time

Question 23

name two drug examples for 0 order kinetics

Answer 23

asprin

alcohol

Question 24

graph of 0 order kinetics on linear graph

Answer 24

linear line

Question 25

The area under the curve (AUC) vs. time for bioavailability plots indicates what

Answer 25

index of extent of drug that enters the bloodstream and thus the body

Question 26

for oral administration, bio-availabilty indicates what

Answer 26

extend of absorption and/or first pass effect

Question 27

define half-life elimination

Answer 27

time needed for a 50% decrease in [ drug plasma]

Question 28

half-life is expressed in units of

Answer 28

time, hours

Question 29

equation for half life for 1 compartment model when Ke is known

Answer 29

.693/ke

Question 30

half life can be used to measure what

Answer 30

how long it takes for a drug to be totally eliminated from body

Question 31

four half lives rule

Answer 31

following 4 half lives, 94% of drug is eliminated and 6% remains in body

Question 32

equation for fraction of drug elminated from body

Answer 32

= 1- 1/(2)^n

Question 33

equation for fraction of drug remaining in body

Answer 33

1/(2)^n

Question 34

definition for volume of distribution

Answer 34

apparent volume that a drug would be distributed within once an equilibrium is established with plasma

Question 35

units for volume distribution

Answer 35

liters/kg

Question 36

what type of volume is volume of distribution

Answer 36

apparent volume

Question 37

large volumes of distribution are indication of a drug that is

Answer 37

highly lipophilic or low protein binding

Question 38

formula for volume distribution

Answer 38

Dose(iv)/ C0

Question 39

volume of distribution can be graphically determined by using what

Answer 39

plasma concentration at time 0

Question 40

define clearance

Answer 40

volume of plasma from which a drug is totally removed per unit of time

Question 41

units for clearance

Answer 41

L/hr or ml/mn

Question 42

formula for clearance

Answer 42

CL - (Ke)(Vd)

Question 43

What is half life of a drug dependent on

Answer 43

clearance and Vd

Question 44

can you use half life along to predict Vd or CL

Answer 44

no

Question 45

assuming single drug administration, [plasma] is directly proportional to what

Answer 45

dose of adminstration

Question 46

formula for calculating amount of drug (A)

Answer 46

A = (C)(Vd)

Question 47

formula for bioavailitbility (F)

Answer 47

AUC oral/ AUC iv

Question 48

if taking drug a second time, how much total drug is in the body

Answer 48

amount of second dose will be added to amount remaining from first dose

Question 49

concentration at steady state (Css) is defined as

Answer 49

average [plasma] maintained at Stead state

Question 50

when Css attained

Answer 50

after 4 half lives

Question 51

flucations between peak and trough and dependent on what

Answer 51

dosing interval

Question 52

longer the dosing interval, what happens to peak and trough

Answer 52

greater variation ini peak and trough values

Question 53

formula for Css

Answer 53

= MD (maintaned dose)/ Cl

Question 54

Maintained dose (MD)

Answer 54

(Dose)(F) / (Dosing interval)

Question 55

what is Css for constant IV infusion

Answer 55

Css = (infusion rate) / (CL)

Question 56

define loading dose

Answer 56

single large dose to produce immediate rise in [drug plasma]

Question 57

formula for loading dose

Answer 57

(Css)(Vd) / (F)

Question 58

dosing interval will have the greatest effect on which parameter for a drug which follows first order kinetics

Answer 58

peak and troughs

Question 59

to obtain stead state of a drug, what is it dependent on

Answer 59

half life