Liver Dysfunction On Pharmacokinetics

Question 1

Where does drug metabolism and elimination occur in the liver

Answer 1

In the heptoacytes using CytochromeP450

Question 2

Where are the blood supplies of the liver from

Answer 2

Hepatic Artery

Portal vein

Question 3

What has more metabolic enzymes liver or intestinal epithelium

Answer 3

Liver

Question 4

What phrase does this statement belong to

- unidirectional ATP-dependant export pumps belonging to ATP-binding cassette

Answer 4

Biliary excretion

Question 5

Hepatic extraction ratio

Answer 5

Fraction of drug entering liver in blood which is removed during one pass of blood through liver

Question 6

What does the hepatic extraction ration depend on

Answer 6

Blood flow
Percent of drug bound to blood
Intrinsic clearance

Question 7

What Eh does high hepatic extraction ratio have

Answer 7

> 0.7

Question 8

What Eh does a low hepatic extraction rate have

Answer 8

<0.3

Question 9

What does the intermediate hepatic extraction ratio have as its Eh

Answer 9

0.3

Question 10

High hepatic extraction ratio -

Does blood flow increase and why

Answer 10

Increases amount of drug present to and eliminated by the organ

Question 11

Hepatic clearance

Answer 11

Volume of blood which is removed completely by liver/ unit time

Question 12

In low hepatic extraction ratio what does the venous drug concentration equal

Answer 12

Arterial concentration

Question 13

Name the 2 steps which occur after oral dose

Answer 13

Absorption in intestinal epithelial cells

Portal circulation

Question 14

What two things is oral clearance determined by

Answer 14

Protein plasma binding

Intrinsic clearance

Question 15

What does systematic clearance assume

Answer 15

Drugs are eliminated by liver

Question 16

What 3 points do we associate with a damaged liver

Answer 16

• high blood binding.
• low unbound fraction in blood.
• significant decrease in drug reversible binding to plasma proteins.

Question 17

Does an oral adminstered drug increase/ decrease intestinal permeability

Answer 17

Increase

Question 18

Does an orally adminstered drug increase/decrease pre-systematic hepatic metabolism

Answer 18

Decrease

Question 19

Does cirrhosis affect drug plasma binding

Answer 19

Yes

Question 20

What does the CL int depend on

Answer 20

Metabolic activity
Activity of the sinusoidal
Canalicular transporters

Question 21

Is CYP450 affected by presence of liver diseases

Answer 21

Yes

Question 22

Why is their impaired bile extraction

Answer 22

-bile duct stones
Cancer of biliary tree
Pancreas

Question 23

What does hepatic disease do for bile extraction

Answer 23

Impair liver function