Updated ASHP/IDSA/SIDP consensus guidance on vancomycin AUC/MIC monitoring replaces trough-only strategy

The ASHP/IDSA/SIDP consensus guidelines ↗ on vancomycin therapeutic drug monitoring, originally published in 2020, have been updated to incorporate two years of real-world implementation data from health systems that transitioned from trough-only to AUC-guided monitoring. The updated guidance reinforces AUC/MIC-guided monitoring (target AUC₂₄ 400–600 mg·h/L for MRSA infections when MIC is ≤1 mg/L) as the standard of care, replacing trough-only approaches (target trough 15–20 mg/L) which are now associated with higher rates of nephrotoxicity without improved efficacy.

Vancomycin's pharmacodynamic target is an AUC/MIC ratio ≥400, making it an AUC-dependent antibiotic. The previous trough-only strategy (15–20 mg/L) was a surrogate for AUC but resulted in AUC₂₄ values of 600–800 mg·h/L in many patients — well above the target range and associated with acute kidney injury (AKI) rates of 15–30%. AUC-guided dosing using Bayesian software achieves the target AUC while using lower doses, reducing nephrotoxicity by approximately 30–60% compared to trough-only targeting. For background on therapeutic drug monitoring principles, see the TDM guide.

The updated guidance provides more specific recommendations for selecting Bayesian software, requiring that tools be validated against real-world vancomycin PK data in the target patient population and demonstrate appropriate handling of renal function changes. Acceptable software must use two-point sampling (an early sample at 1–2 h and a trough sample at steady state) or single-trough Bayesian estimation. The guidance also clarifies that continuous infusion vancomycin monitoring should use Bayesian methods with AUC targets adjusted for the MIC of the infecting organism. See the 2020 original consensus guidelines (NCBI PMC) ↗ for the full derivation.

Health systems implementing AUC-guided vancomycin monitoring should: (1) select a ASHP-endorsed ↗ Bayesian tool with institutional validation; (2) train pharmacists on two-point sampling timing and Bayesian interpretation; (3) establish protocols for initial loading doses (25–30 mg/kg IV) to rapidly achieve the AUC target; (4) define criteria for escalation to alternative agents (e.g., daptomycin, ceftaroline, tedizolid) when AUC targets cannot be achieved without nephrotoxicity. Monitor serum creatinine at least every 48 h during vancomycin therapy. For renal dose adjustment context, see the renal dosing adjustments guide.