4&5- Pharmacokinetics

Question 1

drug delivery via the GI tract

Answer 1

enteral administration

Question 2

drug delivery via a route that does not involve the GI tract. requires piercing the skin

Answer 2

parenteral administration

Question 3

advantage of sublingual and buccal over oral administration

Answer 3

sublingual and buccal enter the venous system and therefore bypass 1st exposure

Question 4

administration via an injection into the subarachnoid space for delivery of drugs into the CNS

Answer 4

intrathecal administration

Question 5

the ________ form is readily able to cross lipid membranes

Answer 5

non-ionized form

Question 6

the non-ionized form of a WA =

Answer 6

protonated WA (aka HA)

Question 7

the non-ionized form of a WB =

Answer 7

unprotonated WB (aka B)

Question 8

where are weak acids better absorbed- stomach or intestine?

Answer 8

stomach

Question 9

where are weak bases better absorbed- stomach or intestine?

Answer 9

intestine

Question 10

when pH

Answer 10

protonated form will predominate if the pH is less than the pKa

Question 11

increase cardiac output = _________ distribution

Answer 11

increase

Question 12

increase regional blood flow = _________ distribution

Answer 12

increase

Question 13

increase capillary permeability = __________ ddistribution

Answer 13

increase

Question 14

increase binding to plasma proteins = _________ distribution

Answer 14

decrease ***

*important

Question 15

increase drug molecule size = _____ distribution

Answer 15

decrease

Question 16

increase lipid solubility of drug = ______ distribution

Answer 16

increase

Question 17

goal of biotransformation

Answer 17

make the molecule more water soluble (more polar) for eventual excretion

Question 18

prodrug

Answer 18

makes use of biotransformation to activate the drug

Question 19

oxidative
reductive
hydrolytic

Answer 19

phase 1 biotransformation

Question 20

cytochrome P450 enzymes

Answer 20

phase 1 biotransformation

Question 21

glucoronidation
sulfation
acetylation

Answer 21

phase 2 biotransformation

Question 22

conjugation

Answer 22

phase 2 biotransformation

Question 23

first pass effect

Answer 23

large percentage of a drug absorbed by stomach or intestine will be carried to the liver by the portal vein and exposed to metabolism before entering circulation –> drug can be inactivated before reaching target

Question 24

primary mechanism of drug elimination

Answer 24

renal excretion

Question 25

increase GFR = ________ filtration

Answer 25

increase

Question 26

increase binding to plasma prtns = ________ filtration

Answer 26

decrease

Question 27

V =

Answer 27

volume of distribution measure of space in body available to contain the drug

Question 28

C =

Answer 28

concentration of drug in blood

Question 29

a low volume of distribution indicates...

Answer 29

most of the drug stays in the blood circulation a higher V would indicate that the drug is highly distributed throughout the body or concentrating somewhere

Question 30

CL=

Answer 30

clearance rate of elimination in relation to drug concentration capacity of drug removal by organs

Question 31

clearance that is independent of drug concentration

Answer 31

zero order elimination

Question 32

concentration of drug has saturate the elimination capacity of the system and mimics zero order kinetics

Answer 32

capacity limited elimination

Question 33

if dosing rate > elimination rate, the concentration will continue to _________ in blood

Answer 33

increase dangerous for toxic effects

Question 34

constant fraction of drug is eliminated

Answer 34

first order elimination

Question 35

the greater the flow the _______ rate of elimination

Answer 35

greater kinetics of flow-limited elimination mimic first order elimination

Question 36

rate of elimination

Answer 36

rate of elimination = k k = 0.693/ t.5

Question 37

accumulation of a drug in the body will be detectable if the dosing interval is shorter than ______ half lives

Answer 37

4

Question 38

amount of drug that reaches systemic circulation

Answer 38

bioavailability

Question 39

ER =

Answer 39

extraction ratio

Question 40

Q =

Answer 40

hepatic blood flow (usually 90)

Question 41

F =

Answer 41

bioavailability

Question 42

f =

Answer 42

extent of absorption (gut)

Question 43

TC =

Answer 43

target concentration

Question 44

what is the therapeutic window?

Answer 44

concentration range between MEC for desired effects and MEC for toxic effects

Question 45

Css =

Answer 45

steady state concentration point during a dosing regimen when elimination of a drug is equal to bioavailability of drug should be within the therapeutic window

Question 46

you will always reach the Css within ____ half lives

Answer 46

4

Question 47

the time it takes to reach Css is _________ of dose or dosing rate but is ___________ upon the half-life

Answer 47

independent dependent

Question 48

dose needed to maintain steady state concentrations

Answer 48

maintenance dose

Question 49

why is decreasing the dosing rate potentially problematic?

Answer 49

this will increase the dosing interval and the peak and trough may excede the therapeutic interval with a larger maintenance dose

Question 50

LD =

Answer 50

loading dose initial dose that can be given in order to achieve the target concentration rapidly