MTM Renal Dosing & Adjustments 2

Question 1

A patient with a CrCl of 25 mL/min is prescribed vancomycin. Which pharmacokinetic parameter is most affected by renal impairment for this drug?

Accepted Answer

Elimination half-life

Answer

Vancomycin is renally eliminated, so its half-life is prolonged significantly as CrCl declines.

Question 2

Which formula is most commonly used to estimate creatinine clearance in clinical practice for renal dosing adjustments?

Accepted Answer

Cockcroft-Gault equation

Answer

The Cockcroft-Gault equation is the standard for estimating CrCl used in drug dosing adjustments in most FDA labeling.

Question 3

A 72-year-old woman weighing 50 kg with a serum creatinine of 1.0 mg/dL is prescribed a renally-cleared drug. Why might dosing based on her normal creatinine be misleading?

Accepted Answer

Low muscle mass can cause falsely normal creatinine despite reduced GFR

Answer

Elderly, low-muscle-mass patients may have reduced GFR despite normal serum creatinine because less creatinine is produced.

Question 4

Which antibiotic requires the MOST significant dose reduction in a patient with CrCl of 10 mL/min?

Accepted Answer

Ciprofloxacin

Answer

Ciprofloxacin is substantially renally eliminated and requires significant dose reduction when CrCl falls below 30 mL/min.

Question 5

When calculating CrCl using the Cockcroft-Gault equation for an obese patient (BMI 42), which weight should generally be used?

Accepted Answer

Adjusted body weight

Answer

Adjusted body weight (IBW + 0.4 × [TBW − IBW]) is recommended for obese patients to avoid overestimating CrCl.

(MTM) Medication Therapy Management Certification for Pharmacists Practice Test

(MTM) Medication Therapy Management Certification for Pharmacists Practice Test

MTM Renal Dosing & Adjustments 2