drug clearance: biotransformation

Question 1

clearance

Answer 1

rate of drug elimination

biotransformation + excretion

Question 2

biotransformation

Answer 2

chemical transformation of a drug by the body

Question 3

excretion

Answer 3

elimination of drug by body

Question 4

does clearance include metabolic and chemical transformation of drug

Answer 4

not necessarily. just chemical and maybe metabolic

Question 5

total body clearance

Answer 5

hepatic biotransformation + renal excretion

Question 6

clearance of polar drugs

Answer 6

eliminated through urine (renal excretion)

-could also be eliminated through air, sweat, saliva

Question 7

clearance of non-polar drugs

Answer 7

goes through hepatic biotransf. to become polar or non-polar metabolites

Question 8

what happens to non-polar metabolites

Answer 8

can either be biotransf. to polar metabolites or eliminated through GI

Question 9

3 ways a drug can be biotransformed

Answer 9

1. activation
2. maintenance of activity
3. inactivation

Question 10

biotransformation (activation)

Answer 10

inactive precursor (prodrug) => active drug

Question 11

biotransformation (maintenance of activity)

Answer 11

active drug => active metabolite

Question 12

biotransformation (inactivation)

Answer 12

active drug => inactive metabolite

Question 13

why is it bad to take alcohol and tylenol

Answer 13

ethanol induces CYP2E1, which will transform acetaminophen to NAPQI (toxic)

Question 14

does a substrate bind to an enzyme in a phase II reaction

Answer 14

no

Question 15

enterohepatic circulation

Answer 15

circulation of drugs from the liver -> bile-> small intestine->liver

Question 16

why is biotransformation important

Answer 16

for enzymatic expression (induction, inhibition); can favour one phase over the other

Question 17

neonates have ___ glucoronidation and renal function

Answer 17

less

Question 18

elderly have ___ CYP and renal function

Answer 18

less

Question 19

factors affecting age-dependent clearance of biotransformation

Answer 19

• body water
• body fat
• liver metabolism
• renal elimination

Question 20

drugs eliminated though the kidney would need a ___ dose for young and old people

Answer 20

lower

Question 21

grapefruit juice inhibits which type of phase transformation

Answer 21

phase I

Question 22

body water ___(decrease/increase) with age

Answer 22

decreases

Question 23

body fat ___(decrease/increase) with age

Answer 23

increases

Question 24

liver metabolism is ___ (high/low) for young and old

Answer 24

low

Question 25

renal elimination is ___ (high/low) for young and old

Answer 25

low

Question 26

solubility and polarity of phase 1 rnx

Answer 26

polar and water soluble

Question 27

what usually happens during phase 1 rnx

Answer 27

unmask or insert functional group

Question 28

most common enzyme for phase 1 rnx

Answer 28

CYP3A4/5 (from the P450 family)

Question 29

is phase 1 rnx enzymes substrate specific?

Answer 29

yes

Question 30

solubility and polarity of phase 2 rnx

Answer 30

polar and water soluble

Question 31

activity of phase 2 rnx metabolite

Answer 31

inactive

Question 32

what happens during phase 2 rnx

Answer 32

involves conjugation of a REACTIVE GROUP *substrate binds to another substrate made by an enzyme

Question 33

what type of enzymes are required for phase 2 rnx

Answer 33

specific transfer enzymes

Question 34

detoxification is usually what phase type

Answer 34

phase 2

Question 35

what happens to metabolites that are formed from phase 2 rnx

Answer 35

eliminated, but some go to bile (store for later)