Evaluation of a once-daily vancomycin regimen in an outpatient Leukemia/Bone Marrow Transplant clinic (OD-VANCO study)

Abstract

Background: The Leukemia/Bone Marrow Transplant Program of British Columbia manages patients with high-risk febrile neutropenia and those with non-neutropenic immunocompromised states in an outpatient clinic setting. Because the program treats outpatients only, once-daily administration of IV antibiotics is desirable. A high-dose, once-daily vancomycin nomogram was developed and implemented as part of the antibiotic treatment regimen. Objective: lb determine if therapeutic vancomycin trough levels could be achieved with a high-dose, once-daily regimen in this outpatient setting. Methods: A prospective, single-centre, observational cohort study was conducted over a 7-month period. Outpatients in the Leukemia/Bone Marrow Transplant Program were started on IV vancomycin with the high-dose, once-daily vancomycin nomogram, and outcomes were assessed. Results: Of 48 outpatients treated over the 7-month period, 10 (21%) had therapeutic vancomycin trough concentrations (i.e., greater than 10 mg/L). Thirty-five (90%) of the 39 patients with suspected clinical infection experienced clinical cure, and 6 (67%) of the 9 patients with documented microbiological infection experienced microbiological cure. Thirty (62%) of the 48 patients experienced symptoms of "red man syndrome", and 7 (15%) experienced some degree of nephrotoxicity. Two of 3 patients with laboratory-reported minimum inhibitory concentration (MIC) for identified pathogens had a calculated area under the curve to MIC ratio greater than or equal to 400. Conclusion: The high-dose, once-daily vancomycin nomogram was effective in attaining trough levels greater than 10 mg/L, in only 21% of patients in this study. A substantial number of adverse drug reactions were observed. Civen these results, high-dose, once-daily vancomycin is no longer recommended for outpatient therapy.