From the Guidelines
Vancomycin dosing should be adjusted based on the patient's renal function, and for a patient with normal renal function, the recommended dose is 15–20 mg/kg/dose (actual body weight) every 8–12 h, not to exceed 2 g per dose, as per the guidelines by the Infectious Diseases Society of America 1. For patients with renal impairment, the dose needs to be adjusted to prevent toxicity. The following adjustments can be considered:
- For moderate renal impairment (CrCl 30-50 mL/min), consider 1g every 24 hours.
- For severe impairment (CrCl 10-30 mL/min), 1g every 48 hours or 500mg every 24 hours may be appropriate.
- In end-stage renal disease (CrCl <10 mL/min), 1g every 72-96 hours is often used. It is essential to monitor therapeutic drug levels, aiming for trough concentrations of 10-15 mg/L for most infections or 15-20 mg/L for severe infections like endocarditis, meningitis, or osteomyelitis, with the first trough level measured before the fourth dose 1. Regular monitoring of renal function during therapy is also crucial, as vancomycin can cause nephrotoxicity, especially when combined with other nephrotoxic agents or in patients with pre-existing kidney disease. Key considerations in vancomycin dosing include:
- Actual body weight for dose calculation
- Renal function assessment through creatinine clearance
- Therapeutic drug monitoring for efficacy and safety
- Regular assessment of renal function to mitigate the risk of nephrotoxicity, as supported by the clinical practice guidelines 1.
From the FDA Drug Label
DOSAGE TABLE FOR VANCOMYCIN IN PATIENTS WITH IMPAIRED RENAL FUNCTION (Adapted from Moellering et al. 1) Creatinine ClearancemL/minVancomycin Dosemg/24 h 1001,545 901,390 801,235 701,080 60925 50770 40620 30465 20310 10155
To determine the renally adjusted dose of vancomycin, we need to know the patient's creatinine clearance. However, since this information is not provided, we cannot calculate the exact dose. The dosage table provides a range of doses based on creatinine clearance, but without this value, we cannot select the appropriate dose. Therefore, the dose of vancomycin 1g every 12 hours may not be the correct renally adjusted dose for a patient with impaired renal function. It is recommended to calculate the creatinine clearance using the provided formula or measure it directly to determine the appropriate dose. In patients with impaired renal function, dosage adjustment is necessary to avoid toxicity, and measurement of vancomycin serum concentrations can be helpful in optimizing therapy 2.
From the Research
Vancomycin Dosing in Renal Impairment
- The dosing of vancomycin in patients with renal impairment is crucial to achieve optimal therapeutic levels while minimizing the risk of toxicity 3, 4.
- A nomogram for vancomycin dosage adjustment based on renal function has been developed, which takes into account the correlation between vancomycin clearance and creatinine clearance 3.
- The nomogram is designed to achieve an average steady-state serum vancomycin concentration of approximately 15 mg/L 4.
Renally Adjusted Dose of Vancomycin
- For patients with normal renal function, a dose of 1g every 12 hours is commonly used 5.
- However, in patients with renal impairment, the dose needs to be adjusted based on the degree of impairment 3, 4.
- A study found that a dose of 1g every 5-7 days is not recommended for patients undergoing hemodialysis with high flux membranes, and instead, monitoring of predialysis plasma levels is necessary to avoid subtherapeutic values 5.
Factors Affecting Vancomycin Dosing
- Renal function, as measured by creatinine clearance, is a critical factor in determining vancomycin dosing 3, 4.
- Augmented renal clearance (ARC) can also impact vancomycin dosing, and patients with ARC may require higher doses to achieve effective therapeutic levels 6.
- The type of dialyzer used can also affect vancomycin clearance, with high flux membranes resulting in lower concentrations 5.