pharmacology: pharmacokinetics

Question 1

what’s F; Cl; vd

Answer 1

F is bioavailability
cl is clearance
vd is volume of distribution

Question 2

first order kinetics vs zero order kinetics

Answer 2

first order: no accumulation

zero order: accumulation

Question 3

first order reaction equation for amount of drug, how to find rate constant

Answer 3

A=A0 - e^(-kt)
A is amount; A0 is initial amt; k is rate constant; t is time
plot ln[A] against t

Question 4

Equation for half-life in first order reactions

Answer 4

t1/2= 0.693/k

Question 5

what is absorption affected by; what order process is it

Answer 5

PH and solubility

first

Question 6

whats volume of distribution; what makes it >1

Answer 6

total amt of drug dosed/[conc of drug in plasma]

it is distributed into tissues. larger vd-> greater distribution

Question 7

how are drugs metabolised? why are they metabolised?

Answer 7

oxidation/conjugation

water-soluble-> easier to excrete

Question 8

what’s clearance
what’s it affected by
sources of clearance
3 equations

Answer 8

vol of plasma cleared of drug per unit time
limited by organ flow
liver/kidneys/metabolic processes
cl= k x vd (k is elimination rate constant)
cl= q x Eh
cl= clearance by liver + kidneys + metabolic processes
cl= dose/auc

Question 9

extraction ratio equation
clearance equation
bioavailability equation
what does it mean if cl > q (liver blood flow)

Answer 9

Eh= (amount removed by liver)/amount entering liver
cl= q x Eh
F= 1-Eh
extra-hepatic clearance present

Question 10

equation to determine oral bioavailability

Answer 10

AUC oral/AUC iv

Question 11

Therapeutic window
safety window
time of action

Answer 11

therapeutic window= c max- c min
safety window= toxicity level- c max
time of action= between onset time to time where min effective conc is reached