Phase 1 drug metabolism Flashcards Preview

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Flashcards in Phase 1 drug metabolism Deck (20):
1

2 outcomes of drug metab.

1. change in activity - more, less, same
2. facilitate excretion - make more water soluble

2

enzyme class that does most drug metabolism

cytochrome P450 - CYP

3

4 ways to make drugs more soluble

1. add functional group
2. oxidation
3. reduction
4. hydrolysis

4

where in the cell is CYP located

on lipid bilayer of ER

5

what is CYP complexed with

NADPH

6

what is basic step to CYP action

uses an Fe and donates e to break an O-O bond and end up with a hydroxylated product

7

**end result of CYP action

adds a hydroxyl group

8

how are so may drugs biotranformed (2)

1. many enzymes
2. broad substrate selevtivity for enzymes

9

what are enzymatic options for outcomes

1. many diff enzymes can make same metabolite
2. single drug can be metabolized in very different reactions

10

how are CYPs named (3)

1. (40% identical at AA level) - same family - first number
2. 55% identical - same subfamily - letter
3. individual members - isoforms - second number

11

what is most common CYP in liver

3A4/5

12

what are 2 possible effects of other substances on these enzymes

1. inhibition
2. induction

13

Why do smokers drink more coffee

the enzyme that breaks down caffeine (CYP1A2) is induced by nicotine

14

why is drinking and tylenol a bad combo

acetominophen has multiple metabolisms, but one (CYP2E1) creates a toxic metabolite (NAPQI) and is induced by alcohol

15

how are enzymes induced

ligands bind to nuclear receptors that set off chain of events leading to new protein expression - not immediate

16

5 generalizations about CYP inducers

1. induce multiple CYPs
2. stimulate their own biotransformation
3. multispecies
4. act in multiple tissue
5. increase rate of gene transcription

17

what is effect of grapefruit juice

inhibitor of CYP3A4, which metabolizes 50% of drugs

18

what are steps of alc. degradation

alc dehydrogenase>acetaldehyde (makes you sick)>aldehyde dehydrogenase> acetic acid

19

what are MAOs

monoamine oxidazes - work on epi, serotonin, dopamine

20

problems with MAOi's

not very specific, so get lots of side effects

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