pharmacokinetics

Question 1

renal excretion terminates actions of what drugs?

Answer 1

small hydrophilic
fully/nearly fully ionized at physiological ph
not protein bound

Question 2

most pharmacologically active drugs are..

Answer 2

lipophilic
unionized / partially ionized
bound to plasma proteins

Question 3

what is the primary determinant of duration and intensity of drug action?

Answer 3

rate of drug metabolism

Question 4

drug metabolism mainly occurs where?

Answer 4

liver in er

Question 5

what other organs can also metabolize substances?

Answer 5

gi mucosa = lower bowel 
kidneys 
lungs 
nasal mucosa 
skin

Question 6

first pass effect

Answer 6

drugs are extensively metabolized during initial pass though the liver

Question 7

what enzymes are involved in phase I ?

Answer 7

CYP450

oxidases

Question 8

what is the most common phase ii rxn?

Answer 8

glucuronidation

Question 9

conjugation using what?

Answer 9

glucorunic acid
sulphate
glutathione

Question 10

what are examples of phase ii rxns?

Answer 10

glucuronidation

methylation

sulfation

n-acetylation

Question 11

codeine, a prodrug, is demethylated to produce

Answer 11

morphine

Question 12

inducers of metabolism

Answer 12

increase synthesis of p450 and reduce degradation

Question 13

inhibitors of metabolism

Answer 13

bind to cytochrome oxidase and inhibit metabolism of other drugs

Question 14

CYP2D6 affects

Answer 14

beta blockers –> alter effect

Question 15

CYP2C9

Answer 15

warfarin –> change dose

Question 16

CYP2C19

Answer 16

omeprazole –> variable response in peptic ulcers

Question 17

what are the most imp routes of drug elimination?

Answer 17

urine and feces

Question 18

what drugs follow zero order kinetics?

Answer 18

ethanol and aspirin

Question 19

ethanol is excreted in …

Answer 19

sweat

Question 20

what’s penicillin?

Answer 20

an acidic antibiotic

Question 21

how are penicillin and aspirin excreted?

Answer 21

via proximal tubular secretion (renal excretion)

Question 22

what is used in the excretion of penicillin and aspirin?

Answer 22

anion transport system

Question 23

what may prolong effects of penicillin?

Answer 23

competition for secretion with probenecid

Question 24

what is aspirin?

Answer 24

acidic salicylate

Question 25

what is given to prevent gout?

Answer 25

aspirin is given to compete with uric acid during distal tubular active reabsorption

Question 26

drug clearance

Answer 26

apparent volume of blood that is cleared of drug per time period

Question 27

clearance equation

Answer 27

U x V / P

Question 28

clearance equation what everything stands for

Answer 28

``` U = urine drug concentration V = rate of urine flow P = plasma drug concentration ```

Question 29

lamda equation

Answer 29

drug in lung blood / drug in lung air

Question 30

what does low / small lambda mean?

Answer 30

short DOA | rapid elimination

Question 31

what does high/large lambda mean?

Answer 31

long DOA | slow elimination

Question 32

rate of elimination equation

Answer 32

plasma drug concentration x clearance

Question 33

general rate equation

Answer 33

``` rate = k x C ^n k = rate constant n = order if zero = 0 if first = 1 ```

Question 34

one compartment model

Answer 34

body is a single compartment drug is rapidly distributed elimination = first order

Question 35

Vd equation

Answer 35

Vd = dose / Co

Question 36

Clearance equation

Answer 36

CL = Vd x ke

Question 37

t 1/2 equation

Answer 37

0.0693 / ke

Question 38

ka aka

Answer 38

absorption

Question 39

ke aka

Answer 39

elimination

Question 40

graph of log plasma drug concentration vs time in one compartment model when drug given via IV dose looks like ?

Answer 40

its linear and negative slope

Question 41

graph of log plasma drug concentration vs time in one compartment model when drug given via oral dose looks like ?

Answer 41

first it rapidly increases ( bc being absorbed) then its linear with a negative slope

Question 42

true or false. t 1/2 depends of dose

Answer 42

false it doesn't depend on dose

Question 43

in 2 compartment model what are the two phases and what do they rep?

Answer 43

S phase = elimination rate constant | F phase = distribution rate constant

Question 44

at steady state what's true about about dosing rate?

Answer 44

dosing rate = elimination rate

Question 45

dosing rate equation

Answer 45

dosing rate = clearance x Css ( steady state concentration)

Question 46

for drugs with first order elimination what does the time to reach Css depend on?

Answer 46

half life of elimination

Question 47

Css is a function of what?

Answer 47

dose dosing interval clearance

Question 48

how many half lives to reach Css 94-97%?

Answer 48

4-5

Question 49

infusion rate equation

Answer 49

CL x Css ( unit = mg/min)

Question 50

dosing rate equation ( maintenance dose)

Answer 50

clearance x desired plasma concentration

Question 51

kinetics for multiple iv ( iv bolus)

Answer 51

dose / T = CL x Css

Question 52

kinetics after multiple oral administration

Answer 52

dose x f ( bioavailability) / T = CL x Css

Question 53

maintenance dose equation

Answer 53

CL x Css x T

Question 54

loading dose equation

Answer 54

loading dose = vd x Css

Question 55

non compartmental clearance eq

Answer 55

cl = dose / auc or cl = Vd x kel

Question 56

non compartmental t1/2 eq

Answer 56

0.693 / k el

Question 57

non compartmental Vd eq

Answer 57

2 (1) dose / Co (2) CL / kel

Question 58

non compartmental bioavailablity eq

Answer 58

auc oral / auc IV x 100