Metabolism

Question 1

What is metabolism?

Answer 1

The chemical conversion of the drug molecule into another chemical entity referred to as a metabolite

Question 2

What 3 things can metabolites be?

Answer 2

Therapeutic , harmful or inative

Question 3

Where does most drug metabolism occur?

Answer 3

In the liver

Question 4

Where can drug metabolism also occur?

Answer 4

Intestine, lungs, kidneys and plasma

Question 5

What is the most effective way of a making a drug inactive or less active?

Answer 5

To render it less fat soluble and more water soluble

Question 6

What does drug metabolism involve?

Answer 6

Phase 1 and 2

Question 7

What do both phases of drug metabolism do?

Answer 7

Decrease lipid solubility and therefore increase renal elimination

Question 8

What is Phase 1?

Answer 8

A chemical reaction that alters the drugs chemical structure

Question 9

What does phase 1 do to the drug? What does this mean?

Answer 9

It makes the drug more water soluble so that it can be excreted in the watery environment of the urine

Question 10

In phase 2 what is the metabolite or drug attached to? What does this create?

Answer 10

A molecules (Conjugation), a larger, polarized molecule

Question 11

Do phase 1 and 2 happen consectively?

Answer 11

Some drugs undergo both phase 1 and 2, some may only undergo one of these phases and some may undergo phase 2 before phase 1.

Question 12

How may some drugs be excreted?

Answer 12

Unchanged, without being actively metabolized

Question 13

What does CYP compromise of? What will these be able to do?

Answer 13

Compromises of a wide range of isoenzymes of which one of more will be able to deactivate almost any given toxin, including drugs

Question 14

What are most drugs treated as in the liver and by what?

Answer 14

Treated as toxins by CYP in the liver

Question 15

Within the CYP450 group what are there subsets of? What are these known as? What are they responsible for?

Answer 15

Enzymes, known as isoforms that are responsible for metabolizing different drugs

Question 16

What CYP groups are involved in drug metabolism?

Answer 16

Groups 1-3

Question 17

What can metabolites be?

Answer 17

Inative or therapeutic

Question 18

What do inactive metabolites do?

Answer 18

Nothing, metabolite has no pharmacological activity

Question 19

What do therapeutic metabolites do?

Answer 19

Good things

Question 20

What does conversion of an active drug to an active metabolite do?

Answer 20

Prolongs the effect of the drug

Question 21

What is a prodrug? Why are they helpful?

Answer 21

Pharmacologically inactive substance that is metabolized to an active substance- it is helpful because it minimizes s/e or helping target drugs to a specific action site

Question 22

Bioavailability

Answer 22

The fraction or percentage of a drug that reaches the systemic circulation unchanged

Question 23

Drugs that enhance enzyme action are called

Answer 23

Induction

Question 24

Drugs that reduce CYP enzyme action

Answer 24

Inhibition

Question 25

What happens if enzymes are induced?

Answer 25

Increased synthesis of enzymes by the liver Induction of CYP will speed up the second drug's metabolism This causes a reduction in plasma concentration This can lead to potential treatment failure

Question 26

What happens in enzyme inhibition?

Answer 26

Decreased synthesis of enzymes by the liver Inhibition of CYP will slow down the second drug's metabolism This leads to an increase in plasma concentration This can lead to toxic levels

Question 27

Why do people have different responses to drugs?

Answer 27

There are differences between people in CYP enzymes