Vancomycin Trough Target Levels
For serious infections, vancomycin trough concentrations should be maintained at 15-20 mg/L to ensure efficacy and minimize toxicity. 1
Target Trough Levels Based on Infection Severity
Serious infections (MRSA bacteremia, endocarditis, osteomyelitis, meningitis, pneumonia):
- Target trough: 15-20 mg/L 1
- This higher range ensures adequate tissue penetration and efficacy against less susceptible strains
Less severe infections:
- Lower trough concentrations may be adequate when treating less invasive infections
- However, the Infectious Diseases Society of America still recommends maintaining therapeutic levels to prevent resistance development
Monitoring Recommendations
- Obtain trough levels before the fourth or fifth dose (at steady state) 1, 2
- For extended therapy, monitor levels twice weekly 1
- Draw trough samples within 30 minutes before the next scheduled dose
Emerging Evidence on AUC-Guided Dosing
Recent evidence suggests that Area Under the Curve (AUC)-guided dosing may be superior to trough-only monitoring:
- AUC-guided dosing is associated with reduced nephrotoxicity compared to trough-guided dosing 3
- Many patients can achieve adequate AUC (≥400 mg·h/L) with trough concentrations <15 mg/L 4
- Trough-only monitoring may lead to unnecessarily high vancomycin exposure and increased toxicity risk 4, 3
Special Considerations
Renal impairment: Dose adjustment based on GFR is necessary 1
- Severe impairment (GFR 15 mL/min): 225 mg every 24-48 hours
- Moderate impairment (GFR 40 mL/min): 600 mg every 24 hours
- Mild impairment (GFR 70 mL/min): 525 mg every 12 hours
Continuous infusion:
- Target plateau concentrations of 20-25 mg/L 5
- May offer more stable drug levels with potentially reduced toxicity
Peritoneal dialysis patients:
- Intermittent dosing may lead to subtherapeutic end-of-dwell concentrations
- Consider continuous vancomycin dosing after a loading dose 5
Nephrotoxicity Considerations
Risk factors for nephrotoxicity include:
- Elevated serum levels
- Underlying renal impairment
- Concomitant nephrotoxic medications
- Extended duration of therapy
Nephrotoxicity is indicated by multiple consecutive increases in serum creatinine (increase of 0.5 mg/dL or 150% from baseline) 1
Higher trough concentrations (15-20 mg/L) are associated with increased nephrotoxicity risk 3, 5
Clinical Pearls
- As long as trough concentrations don't exceed 15 mg/L, peak levels typically remain within safe ranges and don't need routine monitoring 6
- Vancomycin nomograms can help achieve target trough concentrations, but should not replace clinical judgment 2
- Suboptimal vancomycin levels may contribute to the development of vancomycin-intermediate S. aureus (VISA) 5