Exam 1 Study Questions

Question 1

What happens to oral dose after admin?

Answer 1

ADME

A- Drug is dissolved in GIT, enters blood
D- Drug reaches various tissues from systemic circulation
E - After X time, body gets drug through elimination

Question 2

Pharmacokinetics definition

Answer 2

What the body does to the drug

Question 3

biopharmaceutics definiton

Answer 3

influence of physiochemical properties of drugs, dosage forms and physiological factors affecting plasma conc through absorption and distribution.

Question 4

disposition defintion

Answer 4

Interchangeable with Pharmacokinetics

events that occur after drug absoprtion

Encompasses distribution and elimination phases

Question 5

pharmacodynamics definiton

Answer 5

What the drug does to body

Question 6

Distinguish Pharmacokinetic vs Pharmacodynamic variability?

Answer 6

PK: due to variations in drug clearance, 500mg given to 2 ppl but plasma conc different after 2 hrs

PD: plasma conc can be same in 2 ppl but therapeutic response is different

Question 7

What is most important assumption for pharmacokinetic monitoring in patients?

Answer 7

Dose of drugs determined assuming normal functioning of major metabolizing and excretion organs

under normal circumstances, dosage of drug does not change from person to person

reduced clearance of a drug may result in drug accumulation and adverse effects

faster clearance may render the drug ineffective

Question 8

Therapeutic range defintion

Answer 8

Range between minimum effective conc and minimum toxic conc

Question 9

Onset defintion

Answer 9

time for action to start

Question 10

Duration of effect definition

Answer 10

How long drug effect remains, time its above the minimum effective concentration

Question 11

Why do we measure plasma concentration?

Answer 11

to circumvent pharmacokinetic variability and to monitor individualized dosage regimens

Question 12

What are limitations of pharmacokinetics?

Answer 12

lack of clear relation between plasma conc and therapeutic effect

some drugs have wide therapeutic window making plasma conc monitoring unnecessary

Question 13

Most common models in Pharmacokinetics?

Answer 13

one and two compartment model

Question 14

What is 1st pass metabolism?

Answer 14

Drug loss before its entry into systemic circulation

Question 15

How does different route of admin effect bioavailability?

Answer 15

different routes of admin have different onset times, and bioavailability due to either undergoing or missing the 1st pass effect, type of tissue they go through

Question 16

Difference between rate and rate constant?

Answer 16

Rate: depends on conc of reactant

Rate constant: independent of conc of reactant

Question 17

What are the differences between the first and zero-order kinetics when the amount (or concentration)-time data are plotted on linear and semilog graphs?

Answer 17

1st: Normal graph curved, semi log is straight

Zero: Normal is straight, semi log is curved down

Question 18

How is the rate of the process dependent on the amount (or concentration) for zero and first-order processes?

Answer 18

Zero: constant, doesn’t change. flow is same

First: changes with time, faster and first and then gets slower. variable flow

Question 19

What are the assumptions of compartmentalization models?

Answer 19

Drug conc is homogenous

Drug elimination starts immediately after IV bolus injection

Druc conc represent plasma conc

Drug amount represents drug amount in body

Vole equals about/conc in compartment

Question 20

What is apparent volume of distribution?

Answer 20

its not a real volume

Alleged or supposed, its hypothetical

Question 21

What is the significance and application of V?

Answer 21

can show if drug is mostly in plasma (low distribution ~3, <5) or in fat (way higher, 100s+…no upper limit)

Question 22

What are the different routes of drug elimination?

Answer 22

Renal excretion
Metabolism (Primarily Liver)
~~~~~~~~~~~~ 90% ~~~~~~~~~~~~
< 10% excretion into bile
some into sweat and exhaled-air

Question 23

What is the appropriate length of urine collection time in order to estimate the total amount excreted in the urine?

Answer 23

4 half-lives

Question 24

What is renal clearance?

Answer 24

efficacy of the kidneys in excreting the drug

Question 25

What are the advantages and disadvantages of the cumulative method versus the urinary excretion rate method?

Answer 25

Advantage:
Deals with real time points
incomplete bladder emptying does not impact outcome much
Avoid frequent sampling when you want to estimate Au

Disadvantages:
Sampling should be for at least 4 1/2 lives in order to estimate Au

Au cannot be estimated in case of accidental sample loss

Question 26

What are the applications of kinetic parameters obtained from the urine data?

Answer 26

Half0life and elim rate-constant
total amount of drug excreted in urine
unchanged fraction-drug excreted in urine
urinary excretion rate.

Question 27

zero-order reaction Rate and Rate constant

Answer 27

Rate: Doesn’t change with time

Rate constant: Changes with times as the conc changes

Question 28

1st-order reaction Rate and Rate constant

Answer 28

Rate: changes with time as the conc changes

Rate constant: does not change with time