Renal Exam 3 (Pitman filtration and dosing)

Exogenous markers such as inulin are used to give the GFR

Measured GFR

Endogenous markers such as creatinine or cystatin C are used to give GFR

Estimated GFR

Cockcroft-Gault equation output

estimated CrCl, mL/min

CKD-EPI equations outputs

estimated GFR, mL/min/1.73 m2

T/F: Cockcroft-Gault equation can use either cystatin C or creatinine, while CDK-EPI only use serum creatinine

False, it is the opposite

Which is the reference standard GFR? Other is commonly used in practice

Measured GFR

Low muscle mass does what to creatinine production?

Decreases it

Advanced liver disease does what to creatinine production?

Decreases it

Low serum creatinine may lead to…

Overestimates in kidney function

The following medications do what to creatinine secretion (affects how much creatinine is retained in the blood)?

• Trimethoprim

• Cimetidine

• Cobicistat

Decrease, so higher serum creatinine

All of the following affect cystatin C, which one is the only one that DECREASES cystatin C levels?

• Glucocorticoids

• HypERthyroidism

• HypOthyroidism

• Inflammation

• Obesity

Hypothyroidism

Which less affected by muscle mass?

Cystatin C

T/F: both Cockcroft-Gault and CDK-EPI equations can be used to accurately estimate kidney function during AKI development and recovery

False, neither is reliable nor should be used bc both SCr and cystatin C can lag

Indexed eGFR

Normalized to 1.73 m2

Absolute eGFR

Adjusted to patient's actual weight

T/F: GFR and CrCl are interchangeable terms

False

1. Context

2. Drug

3. Reference

4. Fit

5. Follow up

5 steps to renal adjusted dosing

Augmented renal clearance

Enhanced renal function

Why is augmented renal clearance important when considering dosing adjustments?

It can lead to sub-therapeutic responses

Recognize when renal dosing review is needed and assess patient’s kidney function

Context

Identify why kidney function matters for the drug

Drug

Apply guidelines to patient’s current state, ensuring estimations were gathered using the same method

Reference

Determine whether the guidelines are appropriate for this patient right now

Fit

Monitor kidney function, therapeutic response and toxicity

Follow up