infectious diseases
Vancomycin
Dosing Considerations forVancomycin
Doses used for meningitis must be higher than usual. Dose reduction is required in renal insufficiency. In patients with documented or suspected invasive methicillin-resistantS. aureus(MRSA) infection,vancomycinshould be dosed to target an area under the concentration-time curve (AUC) of 400 to 600. Targeting troughs as a surrogate marker for achieving an AUC-to-minimum inhibitory concentration (AUC/MIC) ratio of ≥ 400 is no longer recommended. Dose optimization can be done by getting multiple post-distribution levels (1 to 2 hours after the end of the infusion and a trough) and calculating the AUC using first-order kinetic equations, using a software-based Bayesian approach using 1 or 2 levels, or by titrating a continuous infusion to a steady-state concentration of 20 to 25 mcg/mL (13.8 to 17.25 micromol/L). (See also the2020 therapeutic monitoring of vancomycin for serious methicillin-resistant Staphylococcus aureus infections guidelinesrevised by the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society, and the Society of Infectious Diseases Pharmacists.) These dosing recommendations apply only to MRSA and should not be used to guide dosing for other gram-positive infections. VancomycinMICs for many pathogens have been increasing during the past decade. Sensitivity forS. aureusbased onvancomycinMIC is as follows: ≤ 2 mcg/mL (≤ 1.4 micromol/L): Sensitive 4 to 8 mcg/mL (2.8 to 5.5 micromol/L): Intermediate > 8 mcg/mL (> 5.5 micromol/L): Resistant However, infections due toS. aureuswith avancomycinMIC ≥ 2 mcg/mL (≥ 1.4 micromol/L) may respond suboptimally to standard dosing even when the daily AUC is 400 to 600, so the threshold for changing to an alternative therapy should be low for patients with poor clinical response and an MIC of ≥ 2. 