pharmacokinetics

Question 1

Describe the difference between pharmacokineitics and pharamcodynamics

Answer 1

kinetics - the fate of the drug in the body
dynamics - the effect the drug has on the body

Question 2

What factors effect the blood concetration fo a drug?

Answer 2

size of abminstered dose, Rate of absorption, extent of absorption, extent of distribution, extent of elimination, rate of elimination

Rate - quickly
extent - how much of it

Question 3

What is dependent on the rout?

Answer 3

rate of absorption

Question 4

who takes drugs?

Answer 4

chronic condition or one offs

Question 5

What is the manner that is used to take a drug?

component of this is depednent on what?

Answer 5

dosage regime

duration of therpay and dosage regime is depedent on therapeutic objectives

Question 6

describe pharmacokinetics in more detail

Answer 6

ADME

Question 7

describe pharmacodynamics in more detail

Answer 7

1. relationship between drug concentration at the site of action and pharmacologic response
2. effects include biochemcial or phsyciological effects
3. interaction of drug molecule with recpetor whihc causes initiation of a sequence of molecular events resulting in pharamcologic or toxicological response

Question 8

what is the optimal range for a drug called?

Answer 8

therapuetic window

Question 9

what happens when we have to much or too less of a drug

Answer 9

much - toxic range
less - ineffective range

Question 10

outline the time course of a drug

Answer 10

drug in - concentrtaion in plasma - conctration at site of action - intensity of effect - drug out (if nescessary)

Question 11

in order for a drug to have an effect there must be a certain ___ level of in available in the body at the site of action

Answer 11

ACTive

Question 12

describe one way a drug can become activated?

Answer 12

metabolism

Question 13

Describe the single competment open model in pharmacokinetics

Answer 13

refer to diagram in notes slide 6

Question 14

the rate of change in cocentration over time (dC/dt) in the body (reservoir) in one comprtaemnt is depednetn on several paraemter such as : (expand on these points)

Answer 14

the amount of drug in the reservoir
- size of reservois
- dose given (D)

how well the drug is eliminated
- rate of elimination
- capacity of eliminating organs to remove drug

Question 15

what are the main elimination processes in the body?

Answer 15

zero order kinetics
- constant with no respect to time

first-order kinetics
- never constant with respect to time

Question 16

what two processes are used to predict how long drugs stay in the body

Answer 16

zero and first order kinetics

Question 17

distinuigh betwen zero order and firt order kinetics

Question 18

if we have limited enzymes recptors what order kinetics is it?

Answer 18

zero

Question 19

if we have more enzymes recptors then amount of drug what order kinetics is it?

Answer 19

first

Question 20

rate of trasmfer of drug depends on how much drug drug is availaibe?

Answer 20

first

Question 21

rate of transfer of drug does not depend on how much drug is availaibe?

Answer 21

zero

Question 22

too high a cconcetration of drug in this type leads to saturation of the enzyme

Answer 22

zero

Question 23

for which order kinetics do we use half life to predict the rate of decline?

Answer 23

firts - since delcine with respect to time is cosntant

Question 24

what order of kinetics do most drugs posses?

Answer 24

first

Question 25

what does half life tell us

Answer 25

helps us predict the length of time for a drug to leave the body

also helps us determine how long it takes to reach steady state drug levels in the body after multiple doses

Question 26

what is half life related too?

Answer 26

volume of distribution(Vd) and clearance(Cl)

Question 27

after _ half-lives more then 90% of a drug has left the body

Answer 27

4 ( only 6.25% left in body)

Question 28

Example:

drug X : half life of 2 hrs
drug Y : half life of 8 hrs

1. If miss leonard is given the same dose of these drugs whihc one will take longer to leaev the body
2. whihc drug will have to be dosed more frequently assuming patient complinace

Answer 28

1. Y
2. X

Question 29

what is half life depednt on for zero order kinetics

Answer 29

magnitude of drug concentration

Question 30

how can we alter the halflife of a drug?

Answer 30

changing plasma affinity soo more unbound drug in blood whihc will lead to change in Vd and clearance

Question 31

what is the half life of drug equation

Answer 31

t1/2 = (0.693 VD) / Cl

Question 32

why can’t we use hald life for zero order kinetics?

Answer 32

because it’s always changing same can be said for K (elimination rate constant)