Renal Clearance Flashcards
What is the definition of clearance?
The volume of body fluid cleared of a substance per unit time
Why is clearance a useful measurement?
Working out the method of elimination or metabolism of a drug
Quantitative predictions of plasma concentrations of a substance over time
How do we calculate renal clearance?
Concentration of X in urine x rate of production of urine / Concentration of X in plasma
The top of the fraction is called the excretion rate
What would renal clearance equal to 0 mean?
Neither filtered nor secreted
What would renal clearance less than GFR mean?
Filtered then partially reabsorbed
What would renal clearance equal to GFR mean?
Filtered and not reabsorbed
What would renal clearance less than RPF but greater mean?
Filtered and partially secreted
What would renal clearance equal to RPF mean?
Filtered and secreted
What would renal clearance greater than RPF mean?
Produced in the kidney
What is whole body clearance?
The sum of individual organ clearances
How can we calculate whole body clearance?
Dose over area under curve
Where the graph is plasma concentration vs time
What is the formula for clearance?
Cl=kVd
Whats the formula for concentration over time?
C=Cmaxe^-kt
