Metabolism/ Biotransformation Flashcards Preview

RUSVM Pharmacology > Metabolism/ Biotransformation > Flashcards

Flashcards in Metabolism/ Biotransformation Deck (35):
1

Sites of drug metabolism

Hepatic

Extrahepatic

2

Main organ for drug metabolism

Liver

3

Outcomes of metabolism

Changes in the drug physiochemical properties and pharmacological activity

4

Most drugs are eliminated by the

Kidney

5

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

Metabolites

6

Bioactivation and bioinactivation are possible changes in pharmacological activity due to

Metabolism

7

Liver metabolism may occur in what phases

Phase I- Non synthetic

Phase II- Synthetic conjugation

8

Reactions involved in Phase I liver metabolism

Oxidative reactions

Reductive reaction

Hydrolytic reactions

9

Reactions involved in Phase II liver metabolism

Glucuronide

Sulphate

Methyl

Acetyl

Glycine

Glutamine

10

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

False

11

Goal of Phase I reaction

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

12

Microsomal reactions occur in

Smooth endoplasmic reticulum

13

Non-Microsomal reactions occur in

Cytoplasm or Mitochondria

14

Most common phase I reaction

Oxidation reaction

15

Species that have high oxidative enzyme activity

Horses and Cattle

16

Oxidative reactions are lowest in

Cats and young animals

17

Hydrolysis Reactions

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

18

Fate of drugs that undergo phase I reaction

Inactivation

Active Metabolite

Toxic Metabolite

Product to undergo phase II reaction

19

Phase II Reaction

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

20

Most common phase II reaction

Glucuronidation

21

Species deficient in glucuronidation

Cats

22

Species deficient in acetylation

Dogs

23

Describe the path of a drug given enterally

Systemic circulation > Bile > Small Intestine > Blood

24

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

Emulsification by bile to form micelles

25

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

To stimulate bile secretion

26

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

Less

27

Factors that affect drug metabolism

Age

Individual

Body temperature

Liver disease

Hepatic blood flow

Plasma protein binding

Route of administration

Enzyme induction

Enzyme inhibition

28

Hypothermia (increases/decreases) drug metabolism

Decrease

29

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

Decreases, only unbound drug can be metabolized

30

Enzyme Induction

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

Microsomal enzymes only

31

Enzyme induction and inhibition can lead to

Drug-Drug interactions

32

Enzyme Inhibition

Drugs that inhibit the liver production of certain metabolic enzymes

33

Drugs that are enzyme inducers

Phenobarbital

Rifampin

Phenylbutazone

34

Drugs that are enzyme inhibitors

Chloramphenicol

Cimetidine

Ketoconazole

35

Metabolism

Chemical alteration of the drug by different body tissues