1. pharmcokinetics
Allie punke

2. Critical care
absorption

3. absorption
Passive diffusion OR Carrier-mediated absorption is affected in critically ill patients?
What is the preferred route to feed a critically ill patient? Why?
What class of drugs may further decrease gut blood flow (and therefore absorption)?
If given medication for stress ulcer prophylaxis, how can this affect absorption?
Vasoactive drugs…also, in shock, your body will shunt blood to heart, brain, and lungs.

4. absorption
AB was admitted to the ICU. She is being started on enteral nutrition. What (if any) modifications should be made avoid an interaction with phenytoin?
A. Nothing. It does not interact with phenytoin.
B. Stop the feedings for about 30 minutes when giving phenytoin to prevent a high concentration
C. Stop the feedings for about 2 hours when giving phenytoin
D. The phenytoin dose should be increased to counteract any absorption problems. C

5. absorption
When a patient is receiving enteral nutrition, there are a few medications that interact with the feedings.
Phenytoin
Effect: Dec. serum levels
What to do: Hold tube feedings ~2 hours around dose
Warfarin
Effect: Decreased INR
What to do: Hold tube feedings or increase dose (more so if expecting to be on feedings for long term)
+/- Fluroquinolones
Effect: Maybe decreased levels…maybe not clinically significant. Also, can depend on site of infection (UTI vs bacteremia)

6. Volume of distribution
Critical care
Volume of distribution

7. Volume of distribution
What are some factors that can change Vd in ICU patients?
Giving large volume of fluids
pH changes
Protein binding
Albumin is…. Increased Or decreased in patients?
AAG is….Increased Or decreased in patients?
25% of it stays intravascularly, 75% interstital. Drug may follow the fluid.

8. Volume of distribution
MB is admitted to the ICU. Her pH is Which of the following types of drugs would have an increased volume of distribution?
A. Acidic drugs
B. Basic drugs
C. Neither
D. Both A

9. Volume of distribution
AB is admitted to the ICU and needs to be started on an aminoglycoside. Based on other critically ill patients, AB will also likely require:
A. Higher loading dose
B. Lower loading dose
C. Loading dose will not change
A, B
Follow up: Why did we give AB a higher LD?
A. Increased excretion of the drug
B. Increased volume of distribution
C. Both
D. Neither

10. Volume of distribution
Remember…
Volume of distribution is used to calculate LD
Clearance is used to calculate MD
Be able to take these principles and apply to a patient’s dosing regimen

11. Critical care
metabolism

12. metabolism
Be able to recognize which drugs are low E vs high E (as well as the equations).
Be able to recognize which drugs are bound to albumin vs AAG

13. metabolism
AB is a patient in the ICU. Her albumin level recently fell to 1.9 from 4. Do any of her drugs need to be adjusted?
A. Phenytoin dose needs to be lowered.
B. Phenytoin and morphine doses need to be lowered.
C. Ceftriaxone dose needs to be lowered.
D. Morphine dose needs to be lowered.
D (high E drug) Css,u changes.

14. metabolism

15. metabolism
AB is started on propofol for sedation. Her albumin level is still low around 2.4. Should the propofol dose be adjusted?
A. Yes, the Css and Css,u are both affected.
B. No, neither the Css or Css,u are affected.
C. Yes, because the Css is affected.
D. Yes, because the Css,u is affected. D

16. Critical care
excretion

17. excretion Renal function…. Decreased GFR Difficult to determine
Acute kidney injury possibly may receive CRRT
Fluctuating status of renal excretion

18. Questions?