Traditional weight-based vancomycin dosing is inadequate in critically ill trauma patients

Our aim was to evaluate our institution's compliance with weight-based vancomycin dosing recommendations for pneumonia in critically ill injured patients and to assess the success rate in achieving therapeutic serum vancomycin levels. Additionally, we sought to assess the incidence of vancomycin-induced nephrotoxicity.

All injured intensive care unit (ICU) patients receiving intravenous vancomycin between May 1, 2004 and July 31, 2010 were identified through our trauma database and pharmacy records. The initial weight-based dose was calculated and compared with vancomycin trough levels.

Thirty patients were identified who satisfied the inclusion/exclusion criteria. Only 12 patients (40%) received adequate weight-based dosing (weight-based, 30 mg/kg/day). Weight-based patients weighed significantly less than non-weight-based patients (62.7 vs. 84.2 kg, p = 0.0008). Weight-based patients were more likely to achieve therapeutic trough levels than non-weight-based patients (58 vs. 33%, p = 0.176). Of patients who achieved therapeutic trough levels, more weight-based patients achieved it at first trough than non-weight-based patients (33 vs. 5.6%, p = 0.046).

When prescribing commonly used dosing regimens, appropriate weight-based administration of vancomycin occurred in only approximately one-third of patients. Those patients who did receive weight-based vancomycin dosing were more likely to achieve therapeutic levels, both initially (33 vs. 5.6%) and overall (58 vs. 33%).