Hepatic Clearance Flashcards
1
Q
Hepatic extraction ratio is
A
fraction of drug entering liver in blood tha is irreversibly removed during one pass of blood through the liver
2
Q
Clearance depends on
A
elimination and hepatic blood flow
3
Q
Calculate the clearance:
80% propranolol extracted each pass
liver blood flow 90L/hr
What is the formula for clearance?
A
0.8x90=72L/hr
Cl=HBFxHER
4
Q
HER determinants
A
- unbound fraction - free drug that can diffuse into liver
2. intrinsic clearance: metabolic rate of hepatic enzymes - adjusted out for HBF etc.
5
Q
Low enzyme activity or a low HER means clearance is dependent on what two factors
A
- unbound fracn
2. intrinsic clearance
6
Q
High enzyme activity/ High HER means clearance is dependent on what factor
A
- hepatic blood flow
