1. Pharmacokinetics

2. Venous equilibrium model

3. Venous equilibrium model
Low Extraction Drug:
CL=
F*=
High Extraction Drug:
Low: CL=fup* Clint, F*=1
High: CL=Q, F*=Q/ (fup*Clint)

4. Venous equilibrium model
If a drug has a ER=0.2 and fup is increased, describe what happens to:
Css, IV:
Css,u IV:
Css PO:
Css,u PO:
Css, IV decreased
Css,u IV same
Css PO decreased
CSs,u PO same

5. Venous equilibrium
If a drug has a ER=0.2 and Q is increased, describe what happens to:
Css, IV:
Css,u IV:
Css PO:
Css,u PO:
No effect

6. Venous equilibrium
If a drug has a ER=0.2 and CLint is decreased, describe what happens to:
Css, IV:
Css,u IV:
Css PO:
Css,u PO:
Increase ALL

7. Venous equilibrium
If a drug has a ER=0.9 and CLint is decreased, describe what happens to:
Css, IV:
Css,u IV:
Css PO:
Css,u PO:
Increases Css PO and Css,u PO. Others are the same.

8. Venous equilibrium
If a drug has a ER=0.9 and Q is increased, describe what happens to:
Css, IV:
Css,u IV:
Css PO:
Css,u PO:
Decrease both IV, Same for both PO

9. Venous equilibrium
If a drug has a ER=0.9 and fup is increased, describe what happens to:
Css, IV:
Css,u IV:
Css PO: Won’t ask you
Css,u PO: Won’t ask you
No effect for Css,IV. Increased Css,u IV

10. Venous equilibrium CL Vss T1/2 Low E drugs: Dec Q Inc CLint Inc fup
In notes

11. Venous equilibrium
In notes.

12. Venous equilibrium
A patient has a yeast infection for which his physician prescribed ketoconazole. He is also taking aspirin 81 mg, simvastatin 40 mg, carvedilol 12.5 mg BID, and lisinopril 10 mg. What drug interaction is present?
What happens to:
Vmax Km
Clint
When do you expect this to happen? (Immediately or will it take time?)
Simvastatin + ketoconazole
No change to Vmax, Increase Km (less affinity), Decrease Clint, IMMEDIATELY!

13. Venous equilibrium Rifampin induces the metabolism of a substrate.
What happens to: Km
Vmax
Clint
When do you expect to see this interaction?
Km no change, Vmax is increased, Clint is increased
It will take some time

14. Pharmacokinetics Tutoring
Does the dose rate need to be changed for a drug given orally with the following characteristics when it is administered with an inhibitor:
CL,T=1200ml/min
Fe=0.20
High E drug, Yes it does need to be changed (decreased)

15. Venous equilibrium TIPS: ONLY if Css,u changes would you change DR.
Practice the charts in your notes!
Pay attention to practice questions on recitation.