What should be done for a patient with severe renal impairment and elevated creatinine, who has been on vancomycin for 2 days?

From the Guidelines

For a patient with severe renal impairment and elevated creatinine who has been on vancomycin for 2 days, the dosing regimen should be adjusted immediately to prevent further nephrotoxicity and ensure therapeutic levels are maintained. The patient's vancomycin dose should be reduced and/or the dosing interval extended based on the patient's estimated creatinine clearance, which is crucial in severe renal impairment 1. Given the patient's eGFR of 16 mL/min and creatinine of 283 μmol/L, indicating severe renal impairment, a typical adjustment might be a 15-20 mg/kg loading dose followed by 10-15 mg/kg every 24-48 hours, but this must be individualized 1. It is essential to obtain vancomycin trough levels before the third or fourth dose to ensure the concentration is within the therapeutic range (10-15 μg/mL for uncomplicated infections or 15-20 μg/mL for severe infections) 1. Some key points to consider in managing this patient include:

• Monitoring renal function closely with daily serum creatinine and BUN
• Adjusting the vancomycin dose based on trough levels and renal function
• Considering alternative antibiotics with less nephrotoxicity if renal function continues to worsen
• Being aware that vancomycin is primarily eliminated unchanged by the kidneys, and accumulation due to decreased clearance can lead to further nephrotoxicity and ototoxicity 1. The goal is to balance the need for effective antibiotic treatment with the risk of nephrotoxicity, particularly in a patient with severe renal impairment.

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 appropriate dose, we need to calculate the creatinine clearance. Given the serum creatinine of 283 in Canadian units (which is equivalent to approximately 3.22 mg/dL, considering 1 Canadian unit = 0.0113 mg/dL, but this conversion may not be exact and should be verified), and assuming the patient's weight, age, and sex are not provided, we cannot directly calculate the creatinine clearance using the formula provided. However, we can estimate the creatinine clearance based on the provided table.

Given the eGFR of 16 mL/min, we can look at the dosage table. For a creatinine clearance of approximately 10-20 mL/min, the recommended vancomycin dose is between 10155 mg/24h for a clearance of 10 mL/min.

Since the patient has been on vancomycin for 2 days and has severe renal impairment, close monitoring of serum concentrations of vancomycin is recommended. The dose may need to be adjusted based on the patient's renal function and serum vancomycin concentrations.

Considering the patient's severe renal impairment, maintenance doses of 250 to 1,000 mg once every several days may be more convenient rather than administering the drug on a daily basis. However, the exact dosing interval and amount should be determined based on the patient's specific clinical situation and serum vancomycin concentrations. 2

From the Research

Patient Assessment

• The patient has been on vancomycin for 2 days, with a trough level of 39.8 and an estimated glomerular filtration rate (eGFR) of 16 mL/min, indicating severe renal impairment.
• The patient's creatinine level is 283 in Canadian units, which is elevated.

Nephrotoxicity Risk

• According to 3, vancomycin-induced nephrotoxicity is a significant concern, with an incidence of 10-20% and 30-40% in patients receiving conventional and high doses of vancomycin, respectively.
• The study 4 found that increasing age, body weight, vancomycin dose, and trough levels were associated with significant increases in blood urea and serum creatinine levels, and a reduction in creatinine clearance.
• However, the study 5 suggested that vancomycin loading doses do not increase nephrotoxicity compared to lower doses in patients with severe renal dysfunction.

Management Considerations

• The patient's severe renal impairment and elevated creatinine level suggest a high risk of nephrotoxicity.
• Consideration should be given to monitoring the patient's renal function closely and adjusting the vancomycin dose accordingly.
• Alternative antibiotics, such as daptomycin, may be considered in patients with severe renal impairment, as shown in 6.
• The study 7 found that vancomycin is minimally nephrotoxic and has a similar nephrotoxic profile compared to linezolid when appropriate dosing is used.

Monitoring and Dose Adjustment

• Regular monitoring of the patient's renal function, including creatinine levels and eGFR, is essential to detect any signs of nephrotoxicity.
• The vancomycin dose may need to be adjusted based on the patient's renal function and trough levels, as shown in 5.
• Consideration should be given to using alternative antibiotics or adjusting the dosing regimen to minimize the risk of nephrotoxicity.