When it comes to nephrotoxicity, is vancomycin the chicken or the egg

When it comes to nephrotoxicity, is vancomycin the chicken or the egg?

Vancomycin is a time-dependent killer...so adequate trough levels are key. Guidelines say to keep them over 10 mg/L to prevent bacterial resistance...and between 15 and 20 mg/L to prevent treatment failures of serious staph infections.

But there's not much data to support the safety of trough levels over 10 mg/L...and there's growing evidence that troughs over 15 mg/L might increase the risk for nephrotoxicity.