A patient is receiving vancomycin with an AUC/MIC-guided dosing strategy. The AUC0-24/MIC target for MRSA bacteremia is 400–600 mg·h/L. Compared to trough-only monitoring, AUC/MIC-guided dosing reduces which complication?
- A Vancomycin-associated nephrotoxicity by preventing unnecessarily high trough concentrations (which correlate with AUC), while maintaining therapeutic AUC/MIC targets ✓
- B Risk of Clostridium difficile infection by reducing total drug exposure
- C Risk of ototoxicity by keeping peak concentrations below 35 mg/L
- D The emergence of vancomycin-resistant Enterococcus through lower cumulative drug exposure
Explanation
Vancomycin nephrotoxicity correlates most strongly with AUC24 (total drug exposure over 24 hours) rather than with peak or trough concentrations alone. Traditional trough-only monitoring (targeting 15–20 mg/L) frequently resulted in excessive AUC values and consequent nephrotoxicity without ensuring therapeutic efficacy. AUC/MIC-guided dosing (target AUC0-24 = 400–600 mg·h/L for MRSA) directly measures the relevant pharmacodynamic target, allowing dose optimization that achieves efficacy (AUC/MIC ≥400) while avoiding nephrotoxicity from excessive AUC exposure. The 2020 ASHP/IDSA/SIDP vancomycin monitoring guidelines endorsed this AUC-guided approach. Ototoxicity with modern vancomycin formulations is rare; VRE emergence is primarily an ecological/antibiotic stewardship issue.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
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