Pharmacokinetics

Question 1

What does ADME stand for?

Answer 1

absorption
distribution
metabolism
elimination

Question 2

Equation for concentration you need to know

Answer 2

[C] = Mass/Volume

Question 3

define plasma

Answer 3

blood without cells

Question 4

define serum

Answer 4

plasma without clotting factors

Question 5

What’s the makeup of blood?

Answer 5

50% cells

50% plasma

Question 6

Tissues are perfused with?

Answer 6

blood not plasma

Question 7

What kind of drugs are concentrated in RBCs

Answer 7

highly lipophilic drugs

Question 8

Name these terms Cb, Cp, Css, Cu

Answer 8

Cb = [blood]
Cp = [plasma]
Css = [steady state]
Cu = [unbound]

Question 9

Significance of knowing the [unbound protein]

Answer 9

only unbound proteins are active

Question 10

Pharmacokinetics

Answer 10

what the body does to the drug

how does the drug concentration change as it moves through the different compartments of your body

Question 11

Pharmacodynamics

Answer 11

what the drug does to the body

how does the drug exert its effect on your body

Question 12

Fundamental hypothesis of PK

Answer 12

there is a predictable relationship between plasma (or serum) concentration of a drug and its effect

Question 13

General goals of pharmacokinetics

Answer 13

establishing/adjusting dosage regimens
diagnosis of toxicoses
withdrawal times for food safety in babies

Question 14

Absorption

Answer 14

the process of a drug entering the blood/systemic circulation

Question 15

Distribution

Answer 15

the dispersion of a drug throughout fluids and tissues of the body

Question 16

Metabolism (biotransformation)

Answer 16

the irreversible transformation of parent compounds into daughter compounds

Question 17

Elimination/excretion

Answer 17

the removal of the drug from the body

Question 18

route of elimination/excretion

Answer 18

renal/kidney
gut
lung
skin

Question 19

Drug exposure in the body is a function of what?

Answer 19

both drug concentration and the duration time

Question 20

AUC stands for

Answer 20

area under the curve (always of a single dose)

Question 21

Bioavailability (F)

Answer 21

the fraction (%) of the amount of drug entering into the circulating system

Question 22

Which route of administration has an F of 1

Answer 22

intravenous

Question 23

Which route of administration has a low F

Answer 23

oral

Question 24

What route of administration is faster than oral, but less than 1

Answer 24

intramusclar

Question 25

Equation for F

Answer 25

the amount of a drug absorbed into systemic circulation/the amount of a drug administered

Question 26

Bioavailability is equal to

Answer 26

fraction (%) absorbed from gut lumen into the portal vein X fraction (%) escaping first pass metabolism = 1 - hepatic extraction ratio (Eh)

Question 27

hepatic extraction ratio

Answer 27

the fraction of drug extracted by the liver in the first-pass metabolism

Question 28

What does it mean when you say Eh = 0.5

Answer 28

50% of the drug will be extracted by the liver

Question 29

Eh =

Answer 29

C1 - C2 / C1

Question 30

Another equation for F

Answer 30

AUC (P.O.) / AUC (I.V.)

Question 31

For low Eh drugs

Answer 31

bioavailability is high Most of the dose reaches systemic circulation alteration of the hepatic enzyme activity would not significantly affect the plasma concentration

Question 32

For high Eh drugs

Answer 32

bioavailability is low most of the dose is eliminated by the liver alteration of the hepatic enzyme activity will significantly affect the plasma concentration

Question 33

When are drugs considered bioequivalent?

Answer 33

if the extents and rates of absorption of the drug from them are so similar that there is likely to be no clinically important difference between their effects, either therapeutic or adver

Question 34

Mathematical parameters for considering a drug bioequivalent?

Answer 34

if the 90% Cl of the AUC ratio is within the range of 0.8 - 1.25

Question 35

Relative Bioavailability (Fr) =

Answer 35

AUC generic / AUC brand | 0.8

Question 36

Distribution

Answer 36

the dispersion of the absorbed drug form the site of absorption throughout fluids and tissues of the body

Question 37

factors affecting drug distribution

Answer 37

``` size of organ blood flow solubility binding MW ```

Question 38

volume of plasma in the human body

Answer 38

~2.5 L

Question 39

total body water volume in the human body

Answer 39

40 L

Question 40

total volume of blood in the human body

Answer 40

5.6 L

Question 41

Apparent volume of distribution (Vd) is

Answer 41

the constant relating the amount of drug in the body to the plasma drug concentration

Question 42

Vd =

Answer 42

total amount of drug in the body (A) / plasma drug concentration (Cp)

Question 43

Is Vd constant or related to the drug dose/concentration?

Answer 43

For a specific drug and a specific patient, Vd is a constant

Question 44

steady state

Answer 44

the condition in which the average total amount of drug in the body remains stable over time of dosing ex. the rate of drug input = the rate of drug elimination

Question 45

maintenance dose rate (DR)

Answer 45

rate (mass/time) of drug input to maintain the drug concentration at the stead state

Question 46

what is a loading dose used for?

Answer 46

used to reach the stead state drug concentration more quickly

Question 47

What is Vd important for calculating?

Answer 47

loading dose

Question 48

Loading dose =

Answer 48

Vd * target plasma concentration

Question 49

metabolism

Answer 49

the irreversible transformation of parent compounds into daughter compounds

Question 50

how are most drugs excreted?

Answer 50

by the kidneys

Question 51

clearance (CL)

Answer 51

the efficiency that the drug (vol) is irreversibly eliminated from the volume of distribution

Question 52

elimination rate (ER)

Answer 52

the amount of the drug (mass) is irreversibly eliminated from the dose per unit time

Question 53

Elimination rate constant (K)

Answer 53

the fraction of drug vol is irreversibly eliminated from the vol of distribution per unit time

Question 54

Equation for elimination rate (mass/time) =

Answer 54

clearance (CL) * plasma concentration (Cp)

Question 55

Equation for elimination rate constant (K) =

Answer 55

clearance (CL) / vol of distribution (Vd)

Question 56

increasing the drug plasma concentration will do what to the elimination rate

Answer 56

it will proportionately increase the elimination rate

Question 57

maintenance dose rate (DR) =

Answer 57

clearance (CL) * steady state drug concentration (Css)

Question 58

When the maintenance dose rate remains the same, changing the clearance will do what to the Css?

Answer 58

changing the clearance will proportionately and inversely change the Css

Question 59

When clearance remains stable, increasing the maintenance dose rate will do what to the Css

Answer 59

increasing the maintenance dose rate will proportionately increase Css as well

Question 60

clearance is a description of

Answer 60

efficiency

Question 61

organ clearance (CL) =

Answer 61

organ extraction ratio (E) X organ blood flow (Q) | ex) hepatic: CLh = Eh * Qh

Question 62

for drugs with a high extraction ratio, CL will be mainly determined by

Answer 62

organ blood flow (Qh)

Question 63

For drugs with high hepatic extraction, increasing the hepatic metabolism will?

Answer 63

decrease bioavailability | no change to the clearance

Question 64

For drugs with low hepatic extraction, increasing the hepatic metabolism will?

Answer 64

no change to the bioavailability | clearance will increase

Question 65

What are the implications for blood flow in heart failure?

Answer 65

the blood flow is low