Outcome assessment of minimizing vancomycin monitoring and dosing adjustments

An approach to minimize monitoring of vancomycin therapy was evaluated in 1 20 patients, and results were compared with data from 120 patients in whom vancomycin therapy was monitored and adjusted based on serum peak and troug h concentrations and traditional pharmacokinetic methods. Patients dosed by the nomogram (NM) had regimens adjusted based on actual body weight, estim ated creatinine clearance, and a targeted trough concentration of 5-20 mu g /ml. A single trough serum concentration was drawn only after 5 or more day s of therapy. Overall, the average length of therapy was similar between gr oups (9.9 +/- 9.4 days NM and 8.6 +/- 7.2 days pharmacokinetic). The most c ommon regimen for both groups was 1 g every 12 hours, although NM patients received significantly fewer grams/day (1.9 +/- 0.7 g/day) than the pharmac okinetic group (2.2 +/- 1.0 g/day, p<0.04). Patients dosed by NM also had s ignificantly fewer regimen changes (0.63 +/- 0.96 vs pharmacokinetic 0.92 /- 0.97, p=0.02) as well as significantly fewer serum concentrations measur ed/patient (1.08 +/- 1.9 vs 1.96 +/- 2.0, p=0.001). In addition, serum conc entrations for NM patients were drawn later in therapy (5.4 +/- 2.5 vs 3.8 +/- 3.4 days, p=0.004). Of patients dosed by NM guidelines, 77 had trough c oncentrations drawn; these data were used to validate the nomogram. Seventy -two patients (94%) had trough concentrations in the target range of 5-20 m u g/ml. No differences were found between groups with respect to cure, impr ovement, failure, or days to eradication, or with respect to nephrotoxicity . Finally, total drug cost/patient was not different between groups. A cons iderable cost savings to our institution was noted for patients dosed by NM compared with pharmacokinetics ($232.5 +/- 50.74 vs $403.75 +/- 70.97/mo, p=0.009) based on levels saved. Caution should be applied when generalizing our results to other patient populations.