Metabolism

Question 1

What is phase 1 of metabolism?

Answer 1

most frequently oxidisation, but also reduction

Question 2

What is phase 2 of metabolism?

Answer 2

conjugative or synthetic addition of a large polar molecule that renders the drug water soluable

Question 3

Which organ is the primary organ for metabolism?

Answer 3

Liver

Question 4

What are the main enzymes involved with metabolism in the liver called?

Answer 4

C-450

Question 5

What happens when CYP450 enzymes are increased?

Answer 5

metabolism increases

Question 6

What do the enzymes in the liver do to prodrugs?

Answer 6

convert prodrugs to metabolites

Question 7

What do enzymes in the liver do to active drugs?

Answer 7

convert active drugs to inactive forms

Question 8

What is a metabolite?

Answer 8

byproduct of the body breaking down, or “metabolizing,” a drug into a different substance

Question 9

What happens to lipid (fat) soluble drugs in the kidney?

Answer 9

passively reabsorbed as urine concentrates

Question 10

What are foreign compounds also known as?

Answer 10

xenobiotics

Question 11

CYP450 stand for?

Answer 11

Cytochrome P450

Question 12

What are CYP450 enzymes essential for?

Answer 12

1. metabolism
2. cholesterol
3. Steroids

Question 13

What happens when CYP450 enzymes are not as able to break down drugs?

Answer 13

The effects of the drug and side effects increase

Question 14

What is an effect of CYP450 inhibitors?

Answer 14

May result in drug levels rising in the body

Question 15

What is an effect of inducers of CYP450?

Answer 15

may result in a decrease of the drug levels (and therapeutic value)

Question 16

What does hydrophillic mean?

Answer 16

Attracted to/easily bound to water

Question 17

What does ionisation mean?

Answer 17

Adding or removal of electrons, changing/applying and electrical charge

Question 18

What is a catalyst?

Answer 18

enables a chemical reaction

Question 19

What is conjugation?

Answer 19

the attachment of a chemical group

Question 20

What is oxidisation?

Answer 20

the gain of oxygen, the loss of a hydrogen, or the loss (or partial loss) of electrons

Question 21

What is reduction?

Answer 21

The opposite chemical reaction of oxidisation (the gain of oxygen, the loss of a hydrogen, or the loss (or partial loss) of electrons

Question 22

endogenous

Answer 22

substance that arises from within the body

Question 23

what is metabolism?

Answer 23

the chemical alteration of a substance within the body. lipid (fat) soluable, non-polar compounds into water soluble, polar compounds to enable excretion

Question 24

what is first pass metabolism?

Answer 24

Goes to the liver first

Question 25

what are two consequences of first pass metabolism?

Answer 25

larger dose needed, individual variation and so unpredictability of reactions

Question 26

What are the reactions that usually occur in phase 1 of metabolism?

Answer 26

1. hydrolysis
2. oxidisation
3. reduction

Question 27

What are the outcomes of phase 1 metabolic reactions?

Answer 27

1. Inactivation of the drug
2. activation from a pro-drug to the active form
3. Modification of activity
4. Formation of toxic metabolites

Question 28

What is an example of a pro-drug?

Answer 28

ACE-inhibitors e.g benazepril

Question 29

What is the most common phase 2 reaction in metabolism?

Answer 29

Glucuronidation

Question 30

What phase 2 metabolism reactions are deficient in companion animals?

Answer 30

Glucuronidation and some glucuronyl transferases (cats) and acetylation (dogs).

Question 31

Which species has a poorly developed phase 2 metabolism process?

Answer 31

cats

Question 32

What factors effect drug metabolism?

Answer 32

1. Hepatic impairment
2. Renal impairment
3. Endocrine (hormone) disease e.g. thyroid
4. Drug interactions
5. Species
6. Age
7. weight