What is the recommended dosing of vancomycin for patients with impaired renal function?

Vancomycin Dosing in Renal Impairment

In patients with impaired renal function, vancomycin dosing must be adjusted based on creatinine clearance, with the daily dose approximately 15 times the glomerular filtration rate in mL/min, and an initial dose of at least 15 mg/kg should always be given regardless of renal function severity. 1

Initial Dosing Strategy

• Start with a loading dose of 15 mg/kg in all patients with renal impairment, even those with mild to moderate dysfunction, to rapidly achieve therapeutic concentrations 1
• For critically ill patients with severe infections (bacteremia, endocarditis, pneumonia, meningitis), consider a loading dose of 25-30 mg/kg infused over 2 hours with antihistamine premedication to minimize red man syndrome 2, 3
• The loading dose is independent of renal function and ensures prompt therapeutic levels 1

Maintenance Dosing Based on Creatinine Clearance

The FDA label provides a clear dosing table based on creatinine clearance 1:

• CrCl 100 mL/min: 1,545 mg/24h
• CrCl 90 mL/min: 1,390 mg/24h
• CrCl 80 mL/min: 1,235 mg/24h
• CrCl 70 mL/min: 1,080 mg/24h
• CrCl 60 mL/min: 925 mg/24h
• CrCl 50 mL/min: 770 mg/24h
• CrCl 40 mL/min: 620 mg/24h
• CrCl 30 mL/min: 465 mg/24h
• CrCl 20 mL/min: 310 mg/24h
• CrCl 10 mL/min: 155 mg/24h

The general formula: vancomycin dose (mg/24h) = 15 × creatinine clearance (mL/min) 1

Dosing in Severe Renal Failure and Anuria

• In functionally anephric patients, give an initial 15 mg/kg dose, then maintain with 1.9 mg/kg every 24 hours 1
• For marked renal impairment, it is more practical to give 250-1,000 mg every several days rather than daily dosing 1
• In anuria, a dose of 1,000 mg every 7-10 days is recommended 1, 4
• Research supports that 1 g every 7 days maintains adequate levels in patients with CrCl <10 mL/min 4

Hemodialysis Considerations

• Only 1.5-21.2% of vancomycin is removed during hemodialysis, with dialysis clearance averaging 62.4 mL/min 4
• Plasma concentrations return to pre-dialysis values after dialysis due to redistribution from tissue compartments 4
• Supplemental dosing after dialysis is generally not required unless trough levels are subtherapeutic 4

Therapeutic Drug Monitoring Requirements

• Mandatory trough monitoring is required for all patients with renal dysfunction 2, 5, 3
• Obtain the first trough before the 4th or 5th dose at steady state 2, 5
• Target trough concentrations of 15-20 mg/L for serious infections (bacteremia, endocarditis, osteomyelitis, meningitis, pneumonia) 2, 3
• Monitor serum creatinine at least twice weekly throughout therapy 3
• Recheck trough with each dose adjustment 3

Management of Elevated Trough Levels

• Immediately hold the next dose if trough exceeds 20 mg/L to prevent nephrotoxicity 5, 3
• Recheck trough before administering any subsequent doses 5, 3
• Once trough decreases to 15-20 mg/L, resume at a reduced dose (15-20% reduction) or extended dosing interval 5
• Sustained troughs >20 μg/mL significantly increase nephrotoxicity risk 5

Estimating Creatinine Clearance When Only Serum Creatinine is Available

When measured CrCl is unavailable, use the Cockcroft-Gault equation 1:

• Men: [Weight (kg) × (140 - age)] ÷ [72 × serum creatinine (mg/dL)]
• Women: 0.85 × above value

Critical caveat: This calculation overestimates clearance in shock, severe heart failure, oliguria, obesity, liver disease, edema, ascites, debilitation, malnutrition, or inactivity 1

Common Pitfalls to Avoid

• Never skip the loading dose in renal impairment—therapeutic levels are delayed without it 1
• Never continue the same dose when trough exceeds 20 mg/L—this dramatically increases nephrotoxicity risk 5, 3
• Never rely on peak level monitoring—trough monitoring is the standard of care 2, 3
• Never use standard 1 g every 12 hours dosing in patients with any degree of renal impairment without adjustment 1
• Never assume calculated CrCl is accurate in hemodynamically unstable patients—measure it directly when possible 1
• Never discontinue vancomycin completely when levels are elevated if still clinically indicated—adjust the dose instead 5