Pharmacokinetics

Question 1

What is the therapeutic index?

Answer 1

a measure of drug safety, ratio between the drug/ concentration of the drug producing toxicity and the dose/ concentration that produces a therapeutic effect

Question 2

What does a large therapeutic index mean?

Answer 2

more favourable margin of safety in the drug

Question 3

What does the area under the curve mean?

Answer 3

overall exposure of the body to the drug, reflects the amount absorbed into the bloodstream and how long the drug stays in the system
‘bioavailability’

Question 4

What is volume of distribution defined as?

Answer 4

the theoretical volume needed to dilute the total amount of drug in the body at a given time to acheive the measured plasma concentration

Question 5

What is drug clearance defined as?

Answer 5

the volume of plasma that is completely cleared ofa drug per unit time

Question 6

What is steady-state concentration?

Answer 6

concentration of the drug in the plasma reached when the rate of drug absorption is equal to the rate of drug elimination following repeated or continuous dosing

Question 7

What do zero and first order kinetics refer to?

Answer 7

changes to the amount of a drug as a function of time

Question 8

What is zero order elimination?

Answer 8

a constat amount of drug eliminated per unit of time

Question 9

What is first order elimination?

Answer 9

a constant fraction of a drug is eliminated per unit time- as the concentration drops, the elimination rate drops as well

Question 10

What is the drug elimination half life?

Answer 10

the time taken for the drug plasma concentration to decrease by 50%, calculated during the elimination phase

Question 11

What is drug bioavailability?

Answer 11

Drug Bioavailability is the fraction of administered dose
of the parent drug that reaches the systemic circulation.

Question 12

What kind of administration will have the highest bioavailability?

Answer 12

iv (100%)

Question 13

What is volume of distribution?

Answer 13

is defined as the theoretical volume needed to dilute the total amount of drug in the body at a given time to achieve the measured plasma concentration

Question 14

What is the volume of distribution calculation?

Answer 14

Administered dose over the plasma concentration

Question 15

What is the definition of drug clearance?

Answer 15

efficiacy of drug elimination

Question 16

What is overall drug clearance the sum of?

Answer 16

the sum of hepatic clearance + renal
clearance + clearance by other routes

Question 17

What is steady-state concentration?

Answer 17

is the concentration of drug
in the plasma reached when the rate of drug absorption is equal to the
rate of drug elimination following repeated or continuous dosing

Question 18

What is the function of a loading dose?

Answer 18

• Loading dose administered at the start of therapy
• Steady-State is then reached quicker

Question 19

What is the one-compartment model?

Answer 19

drug is absorbed from its site of administration into a single central
compartment

Question 20

What is the two compartment model?

Answer 20

All drugs are distributed, to some extent, into tissues
* Two-compartment models describe the pharmacokinetics of
most drugs