Metabolism/ Biotransformation

Question 1

Sites of drug metabolism

Answer 1

Hepatic

Extrahepatic

Question 2

Main organ for drug metabolism

Answer 2

Liver

Question 3

Outcomes of metabolism

Answer 3

Changes in the drug physiochemical properties and pharmacological activity

Question 4

Most drugs are eliminated by the

Answer 4

Kidney

Question 5

Drugs are usually converted to ____________ that are more water soluble, polar and ionized than parent drugs

Answer 5

Metabolites

Question 6

Bioactivation and bioinactivation are possible changes in pharmacological activity due to

Answer 6

Metabolism

Question 7

Liver metabolism may occur in what phases

Answer 7

Phase I- Non synthetic

Phase II- Synthetic conjugation

Question 8

Reactions involved in Phase I liver metabolism

Answer 8

Oxidative reactions

Reductive reaction

Hydrolytic reactions

Question 9

Reactions involved in Phase II liver metabolism

Answer 9

Glucuronide

Sulphate

Methyl

Acetyl

Glycine

Glutamine

Question 10

T/F: All drugs undergo both Phase I and Phase II liver metabolsim

Answer 10

False

Question 11

Goal of Phase I reaction

Answer 11

To produce reactive molecules that can conjugate with a polar molecule in phase II

Question 12

Microsomal reactions occur in

Answer 12

Smooth endoplasmic reticulum

Question 13

Non-Microsomal reactions occur in

Answer 13

Cytoplasm or Mitochondria

Question 14

Most common phase I reaction

Answer 14

Oxidation reaction

Question 15

Species that have high oxidative enzyme activity

Answer 15

Horses and Cattle

Question 16

Oxidative reactions are lowest in

Answer 16

Cats and young animals

Question 17

Hydrolysis Reactions

Answer 17

Addition or loss of an electron, often can produce more reactive metabolite that than may have

Question 18

Fate of drugs that undergo phase I reaction

Answer 18

Inactivation

Active Metabolite

Toxic Metabolite

Product to undergo phase II reaction

Question 19

Phase II Reaction

Answer 19

Combination of a molecule with a reactive group capable of attaching a substituent group

Question 20

Most common phase II reaction

Answer 20

Glucuronidation

Question 21

Species deficient in glucuronidation

Answer 21

Cats

Question 22

Species deficient in acetylation

Answer 22

Dogs

Question 23

Describe the path of a drug given enterally

Answer 23

Systemic circulation > Bile > Small Intestine > Blood

Question 24

What allows fat soluble drugs to diffuse into the aqueous intestinal environment?

Answer 24

Emulsification by bile to form micelles

Question 25

Why is it a good idea to give fat soluble drugs with a meal?

Answer 25

To stimulate bile secretion

Question 26

Young animals have (more/less) metabolic capacity than adult animals

Answer 26

Less

Question 27

Factors that affect drug metabolism

Answer 27

Age

Individual

Body temperature

Liver disease

Hepatic blood flow

Plasma protein binding

Route of administration

Enzyme induction

Enzyme inhibition

Question 28

Hypothermia (increases/decreases) drug metabolism

Answer 28

Decrease

Question 29

Increased drug bound to plasma proteins (increases/decreases) meabolism

Answer 29

Decreases, only unbound drug can be metabolized

Question 30

Enzyme Induction

Answer 30

Drugs that increase synthesis, decrease degradation and or activate pre existing compounds _________________________________

Microsomal enzymes only

Question 31

Enzyme induction and inhibition can lead to

Answer 31

Drug-Drug interactions

Question 32

Enzyme Inhibition

Answer 32

Drugs that inhibit the liver production of certain metabolic enzymes

Question 33

Drugs that are enzyme inducers

Answer 33

Phenobarbital

Rifampin

Phenylbutazone

Question 34

Drugs that are enzyme inhibitors

Answer 34

Chloramphenicol

Cimetidine

Ketoconazole

Question 35

Metabolism

Answer 35

Chemical alteration of the drug by different body tissues