Pharmacokinetics

Question 1

what factors affect the passage drugs across membranes

Answer 1

regional blood flow
extracellular binding
capillary permeability

Question 2

define first pass metabolism

Answer 2

the fraction of drug lost during absorption and metabolism by the liver after its first cycle in the boyd

Question 3

define enterohepatic circulation

Answer 3

the movement of drugs from the gut to the liver via the hepatic portal vein, into the bile salts and then into the gut again. this repeats

Question 4

define drug half-life

Answer 4

time taken for the concentration of drug to fall to half its original volume

Question 5

define apparent volume of distribution

Answer 5

the volume in which a drug appears to be disturbed

Question 6

define bioavailability

Answer 6

the proportion of administered drug that is available within the body to exert its pharmacological effect

Question 7

define drug clearance

Answer 7

the volume of blood (plasma) which can be cleared of a drug in a certain unit of time

Question 8

what is the CYP450 enzyme system mainly involved in

Answer 8

drug metabolism

particularly phase 1 oxidation reactions

Question 9

what are the processes in phase 2 metabolism

Answer 9

glucuronidation 
acetylation 
amino acid conjugation 
sulphation 
methylation 
glutathione conjugation

Question 10

what are the processes in phase 1 metabolism

Answer 10

oxidation (the main one)
reduction
hydrolysis