ADME lab

Question 1

organ clearance of a drug is influenced by:

Answer 1

• organ blood flow
• plasma protein binding
• organs intrinsic ability to eliminate the drugs
  (so larger drug dose does not change the clearance values)

Question 2

if a drug has high renal clearance - what does it imply about the filtration through the kidney

Answer 2

will probably be both filtered and actively transported from the blood to the urine

Question 3

what is the difference between pharmacokinetic half life and the normal half life of a drug

Answer 3

pharmacokinetic half life - the half life of the drug in the plasma
half life - the half life of the drug in the body

Question 4

if drug A is eliminated from the body slower than drug B, what would you expect the half life of drug A to be compared to drug B

Answer 4

longer

Question 5

how do we measure drug clearance

Answer 5

(fractional single pass elimination) x (blood flow rate of the organ)

Question 6

what is the bioavailability of a drug

Answer 6

the proportion of the drug that reaches the systemic circulation in an active form

Question 7

does oral or IV administration lead to longer lasting drug concentrations and why

Answer 7

oral - because the release is delayed

IV will have higher and faster conc, but oral will have longer effect

Question 8

what are three ways in which a drug may have bioavailability of less than 100%

Answer 8

• first pass metabolism in the liver
• incomplete drug absorption
• bacterial metabolism in the intestine (if via oral absorption)

Question 9

what is the volume of distribution

Answer 9

the volume into which the total amount of drug in the body would need to be dissolved to achieve the conc that is observed in the blood