Drug Metabolism and Excretion Flashcards

1
Q

Explain the importance of drug metabolism; dosing, safety.

A
  • Dosing issue

–> metabolism /clearance determines amount of drug at site of action and so steady state levels

-Safety

–> Daughter compounds may have side effects

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2
Q

Define and describe the two phases of drug metabolism: PHASE 1

A

PHASE 1

–> Add oxygen molecules to C/N/S in drug and this is done by Cytochrome P450 enzymes

-Oxygen binds to drug and other oxygen atom (o2) is reduced to water

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3
Q

Define and describe the two phases of drug metabolism: PHASE 2

A

PHASE 2

–> Conjugation of Phase 1 product with glucose increasing water solubility

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4
Q

Explain the role of drug metabolism in paracetamol overdose.

A
  • No phase 1 metabolism

- phase 2 includes glucuronidation preventing doormat n of toxic quinone-mine

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5
Q

Describe the factors influencing drug metabolism and elimination.

A
  • Age

–> Cytochrome P450 activity reduced in elderly/neonates

–> GFR reduced

–>Increased fat content in elderly

-Genetics

–> slow metabolism

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6
Q

Drug metabolising enzymes (induced/inhibited by other drugs).

A

–> Disease = liver toxicity, renal disease

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7
Q

Outline the general appreciation needed of ADME when prescribing

A
  • Compliance
  • Toxicity
  • Drug interactions
  • Therapeutic effets
  • Individualise therapy
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