What is the 'Extraction Ratio' ($ER$) of an organ like the liver?
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Correct answer: The fraction of drug removed from blood in a single pass through the organ
The extraction ratio measures an organ's efficiency in removing a drug. For a high $ER$ drug, clearance is limited by blood flow to the organ, whereas for a low $ER$ drug, clearance is limited by the organ's enzymatic capacity.
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More Half-Life and Clearance questions
- If the dosing rate of a drug is doubled during a continuous IV infusion, what happens to the steady-state plasma concentration ($Css$)?
- Which of the following would lead to an increase in the Volume of Distribution ($Vd$) and a subsequent increase in half-life?
- The 'Maintenance Dose' of a drug is primarily determined by which pharmacokinetic parameter?
- What happens to the time required to reach steady state if the infusion rate of a drug is increased?
- A 'Loading Dose' is administered to:
- If a drug has a Clearance of 2 L/hr and a Volume of Distribution of 40 L, what is its approximate half-life?