Evaluation of a method for initiating vancomycin therapy: experience in 205 patients

Abstract

This study evaluated a dosing method for initiating vancomycin therapy in a large population based on patients' age, weight, and renal function. The aims were to determine the method's efficacy in achieving predetermined peak and trough serum concentrations, and to calculate the cost savings incurred by individualizing therapy. Average doses +/- 1 SD of 7.93 +/- 0.29 mg/kg corrected body weight (lean body weight + 40% excess weight) were administered at intervals predicted by the patients' estimated creatinine clearances (range 22-130 ml/min). The calculated mean dose +/- SD was 558 +/- 83 mg (range 350-750 mg) and the calculated median interval was 12 hours (range 6-24 hr). Peak and trough concentrations +/- SD measured at steady state averaged 26.0 +/- 5.4 and 7.3 +/- 2.3 micrograms/ml, respectively. Peak and trough serum concentrations fell within the predetermined therapeutic range in 311 (76%) of 410 samples. Peak concentrations were in the range of 20-30 micrograms/ml in 145 (71%) of 205 samples. Trough concentrations were in the range of 5-10 micrograms/ml in 166 (81%) of the 205 samples. This simplified dosing method successfully individualized therapy in most patients, and produced a significant savings to the pharmacy in reduced drug acquisition costs and to patients in reduced drug charges.