Vancomycin serum concentration during febrile neutropenia in patients with acute myeloid leukemia

Adult leukemia patients with febrile neutropenia have a higher volume of distribution requiring increased drug doses. We performed a survey of vancomycin use in that population to assess the accuracy of our dosing guidelines.

We retrospectively reviewed the charts and laboratory results of vancomycin prescription and monitoring in adult acute myeloid leukemia patients with febrile neutropenia in a teaching hospital.

Fifty-four patients received 67 vancomycin courses between January 2005 and April 2007. A loading dose was used in 97% of cases dosed at a mean 15.5±3.3mg/kg. It was followed by a continuous infusion of an average 35.4±6.9mg/kg per day maintenance dose. Serum monitoring yielded serum levels above the 20mg/L target in only 12% of cases. Despite higher dose, the target concentration was only reached in 32% of cases, after a mean 1.5 dose adjustment. The mean final maintenance dose was 42.1±9.4mg/kg per day. Vancomycin was well tolerated and induced only two temporary increases in serum creatinine. The treatment was microbiologically justified in only two cases. The mean length of therapy was 7.7±4.4 days and 41 over 65 (63%) non-documented infections were treated for more than five days despite local guidelines recommending a maximum 5-day course without bacterial documentation. Overall, only seven (10%) vancomycin courses complied with all defined criteria.

Vancomycin use was not optimal. We updated our guidelines after the study to dramatically reduce vancomycin indications in leukemia patients. When it is indicated, following the loading dose, we more closely monitor vancomycin serum levels to allow for an earlier dose adjustment when necessary.