Introduction: Current dosing practice of vancomycin is directed to achieve goal vancomycin troughs of 15–20 mcg/mL in patients with sepsis; however, this goal was derived from a correlation between troughs and area under the curve (AUC) concentrations in medically ill patients. Critically ill trauma patients have several innate and acquired factors that alter drug clearance and pharmacokinetic properties. Methods: Adult trauma patients in the intensive care unit requiring vancomycin for sepsis were eligible. Exclusion criteria included ICU length of stay less than 24 hours, acute or chronic renal dysfunction, pregnancy or allergy to vancomycin. Patients received vancomycin 20 mg/kg (based on actual body weight) every 12 hours. Vancomycin levels were drawn during the estimated steady state period. Levels were drawn prior to the start of the infusion, immediately after the infusion, and at hours 4, 6, and 12. Individualized AUC’s were calculated using the trapezoidal rule. Results: Patient specific pharmacokinetics were assessed in fourteen patients. The median age of the patients was 36.5 years (range 21–54 years). The median dose received was 1625 mg at an every 12 hour interval (range 1,250–2,500 mg). The median trough at steady state was 9 mcg/mL (range 4.5–15.5 mcg/mL) and the median 24-hour AUC was 358.4 mcg/h/mL (range 322-760mcg/h/mL). An effective AUC:MIC for an MIC of 1 is obtainable by achieving a trough of 15–20 mcg/mL. However, to reach an effective AUC:MIC for an MIC of 1.5 and 2 would require median doses of 38 mg/kg/dose every 12 hours and 48 mg/kg/dose every 12 hours respectively. Conclusions: These higher dosing regimens are nearly impossible to practically utilize due to the relative dose ceiling of vancomycin. In our population current dosing methods of vancomycin are inadequate in achieving target AUC’s in critically ill trauma patients when MIC’s are above 1. Alternative dosing methods or therapeutic options should be considered in this population.
1Grady Health System, Atlanta, GA, 2Medical University of South Carolina, Charleston, SC, 3Emory University, Atlanta, GA