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Flashcards in Metabolism and Pharmacokinetics Deck (64)
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1

What is drug metabolism?

Biochemical modification of pharmaceutical sibstances by living organisms usually through specialised enzymatic activity

2

What does metabolism limit?

The life of a substance in the body by rendering lipid soluble and non-polar compounds to water soluble and polar compounds than can be excreted

3

What substances are excreted?

Water soluble

4

What substances are reabsorbed back into the blood from renal sites?

Lipid soluble

5

What are some sites of drug metabolism?

Liver

Lining of gut

Kidneys

Lungs

6

What is the purpose of drug metabolism?

Increase water solubility and aid excretion

Deactivate compounds

7

What are prodrugs?

Drugs that may be activated following metabolism

8

What are examples of prodrugs?

Codeine

Enalpril

Simvastatin

Sacbitril

9

What are the effects of metabolism?

Loss of pharmacological activity

Decrease in activity, with metabolites that show some activity

Increase in activity, more active metabolites (activation of prodrug)

Production of toxic metabolites

10

What can different kinds of toxic metabolites do?

Direct toxicity

Carcinogenesis (formation of a cancer)

Teratogenesis (congenital malformations produced in an embryo)

11

What is carcinogenesis?

Formation of a cancer

12

What is teratogenesis?

Congenital malformations produced in an embryo

13

What happens to a prodrug during metabolism?

Inactive chemical compound is coverted into its active metabolite

14

What controls the metabolism of drugs?

Enzymes

15

What can you say about the specificity of enzymes that metabolise drugs?

They have a wide range of specificity so individual drugs are often metabolised by more than one

16

How can different enzymes be expressed?

Constitutively (constant amounts)

In the presence of particular substance

17

What are the 2 phases of metabolism?

Phase 1 (activation/inactivation)

Phase 2 (conjugation products)

18

What are different phase 1 reactions?

Oxidation

Reduction

Hydrolysis

19

What happens during phase 1?

Polar groups are introduced to the molecule

20

What does increasing the polarity of compounds during phase 1 do?

Provides an active site for phase 2 metabolism

21

What is the most important superfamily of metabolising enzymes?

Cytochrome P-450

22

What does drug specificity of an enzyme depend on?

Which isoform of cytochrome P-450 is being used

23

What are the 3 families of the cytochrome P-450 super family used in oxidative drug metabolism?

CYP1

CYP2

CYP3

24

What is CYP1A2 important in the metabolism of?

Theophylline

25

What is CYP1A2 induced by?

Smoking

26

What is CYP2D6 important for the metabolism of?

Some antidepressants, antipsychotics and conversion of codeine to morphine

27

What is CYP2D6 induced by?

Smoking

28

Where is CYP3A4 found?

In the liver and the gut

29

What is CYP3A4 important for?

Pre-systematic (first pass) metbaolism of several drugs

30

What are examples of drugs that CYP3A4 is important for the metabolism of?

Diazepam

Methadone

Simvastatin

CCBS