Chapter 4: Drug Metabolism

Question 1

[_____] reactions include oxidation, reduction, deamination, and hydrolysis.

Enzymes are found in high concentrations in the smooth endoplasmic reticulum of the liver.

Answer 1

Phase I reactions

Question 2

Examples of phase I drug-metabolizing reactions.

Answer 2

Oxidations, P450 dependent
Oxidations, P450 independent
Reductions
Hydrolyses

Question 3

Reaction type: Oxidations, P450 dependent

Answer 3

Hydroxylation
N-dealkylation
O-dealkylation
N-oxidation
S-oxidation
Deamination

Question 4

Reaction type: Oxidations, P450 independent

Answer 4

Amine oxidation

Dehydrogenation

Question 5

Reaction type: Hydrolyses

Answer 5

Esters

Amides

Question 6

[_____] reactions are synthetic reactions that involve addition (conjugation) of subgroups to —OH, —NH2, and —SH functions on the drug molecule.

The subgroups that are added include glucuronate, acetate, glutathione, glycine, sulfate, and methyl groups.

Most of these groups are relatively polar and make the product less lipid-soluble than the original drug molecule.

Answer 6

Phase II Reactions

Question 7

Examples of phase II drug-metabolizing reactions

Answer 7

Glucuronidation
Acetylation
Glutathione conjugation
Glycine conjugation
Sulfation
Methylation

Question 8

Of the drugs metabolized by phase I cytochrome P450s, approximately 75% are metabolized by just two:

Answer 8

CYP3A4/5 or CYP2D6