What vancomycin trough level targets are used for serious infections such as bacteremia?

• A. 5-10 mg/L
• B. 15-20 mg/L
• C. 25-30 mg/L
• D. 0.5-1.0 mg/L

Answer: (B)

In serious infections, vancomycin exposure must be high enough to achieve effective bacterial killing, and trough levels are used as a practical proxy to gauge that exposure over the dosing interval. Targeting a trough around 15-20 mg/L is commonly recommended because it tends to produce an AUC24/MIC of about 400 or higher when the pathogen’s MIC is 1 mg/L, which is the level associated with good outcomes for serious infections like bacteremia. This range aims to maximize efficacy while keeping the risk of nephrotoxicity in check.

Lower troughs, such as 5-10 mg/L, are often subtherapeutic for bacteremia and other severe infections, risking treatment failure. Higher troughs, like 25-30 mg/L, raise the chance of kidney injury without proven additional benefit for most pathogens with typical MICs. While current practice increasingly emphasizes AUC-guided dosing rather than troughs alone, the 15-20 mg/L range remains a common, effective target for serious infections.