Liver Extraction Ratio Quiz

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What does the liver extraction ratio (ER) measure?

General distribution of the drug in the body

Drug concentration in the liver

Blood flow to the liver

Drug removal from the liver after oral administration (correct)

What does an ER of 0.25 indicate?

100% of the drug is removed by the liver

75% of the drug is removed by the liver

25% of the drug is removed by the liver (correct)

50% of the drug is removed by the liver

How is hepatic clearance (Clh) calculated if both the ER and the blood flow to the liver are known?

Clh=Q-ER

Clh=Q×Ca-Cv/Ca

Clh=Ca/Cv

Clh=Q×ER (correct)

Why is sampling of drug from the hepatic portal vein and artery difficult?

It requires invasive procedures in humans Signup and view all the answers

Why may animal ER values be quite different from those in humans?

There are variations in drug metabolism between animals and humans Signup and view all the answers

Which factor(s) affect the hepatic clearance of a drug?

All of the above Signup and view all the answers

What is the relationship between bioavailability (F), liver extraction (ER), and fraction of drug removed by nonhepatic process (F″)?

$F = 1 - ER - F″$ Signup and view all the answers

For drugs with very high extraction ratios, how does the rate of drug metabolism respond to changes in hepatic blood flow?

The rate of drug metabolism increases with increased hepatic blood flow Signup and view all the answers

What is used to describe the total ability of the liver to metabolize a drug in the absence of flow limitations?

Intrinsic clearance Signup and view all the answers

What can increase the intrinsic clearance for the metabolism of many drugs?

Smoking Signup and view all the answers

What does a liver extraction ratio (ER) value of 0.25 indicate?

75% of the drug is removed by the liver Signup and view all the answers

How is hepatic clearance (Clh) calculated when both the liver extraction ratio (ER) and the blood flow to the liver are known?

$Clh = Q \times ER$ Signup and view all the answers

What factor(s) affect the hepatic clearance of a drug?

Blood flow to the liver and drug concentration in blood Signup and view all the answers

Why may animal ER values be quite different from those in humans?

Variability in hepatic blood flow between animals and humans Signup and view all the answers

What does the liver extraction ratio (ER) provide a direct measurement of?

Drug removal from the liver after oral administration Signup and view all the answers

In the context of hepatic clearance, what is the significance of intrinsic clearance (Clint)?

It reflects the inherent ability of the liver to metabolize a drug, unaffected by blood flow. Signup and view all the answers

What characterizes drugs with high extraction ratios in terms of hepatic clearance?

Their clearance is sensitive to changes in hepatic blood flow. Signup and view all the answers

What factor primarily affects drugs with low extraction ratios in terms of hepatic clearance?

Changes in intrinsic activity of mixed-function oxidases. Signup and view all the answers

How does propranolol, a beta-adrenergic blocking agent, affect its own hepatic clearance when given orally?

It decreases hepatic blood flow, resulting in slower clearance. Signup and view all the answers

What condition can increase the intrinsic clearance for the metabolism of many drugs?

Smoking Signup and view all the answers

Liver Extraction Ratio Quiz

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Questions and Answers

What does the liver extraction ratio (ER) measure?

What does an ER of 0.25 indicate?

How is hepatic clearance (Clh) calculated if both the ER and the blood flow to the liver are known?

Why is sampling of drug from the hepatic portal vein and artery difficult?

Why may animal ER values be quite different from those in humans?

Which factor(s) affect the hepatic clearance of a drug?

What is the relationship between bioavailability (F), liver extraction (ER), and fraction of drug removed by nonhepatic process (F″)?

For drugs with very high extraction ratios, how does the rate of drug metabolism respond to changes in hepatic blood flow?

What is used to describe the total ability of the liver to metabolize a drug in the absence of flow limitations?

What can increase the intrinsic clearance for the metabolism of many drugs?

What does a liver extraction ratio (ER) value of 0.25 indicate?

How is hepatic clearance (Clh) calculated when both the liver extraction ratio (ER) and the blood flow to the liver are known?

What factor(s) affect the hepatic clearance of a drug?

Why may animal ER values be quite different from those in humans?

What does the liver extraction ratio (ER) provide a direct measurement of?

In the context of hepatic clearance, what is the significance of intrinsic clearance (Clint)?

What characterizes drugs with high extraction ratios in terms of hepatic clearance?

What factor primarily affects drugs with low extraction ratios in terms of hepatic clearance?

How does propranolol, a beta-adrenergic blocking agent, affect its own hepatic clearance when given orally?

What condition can increase the intrinsic clearance for the metabolism of many drugs?

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