Mississippi mud no more: cost-effectiveness of pharmacokinetic dosage adjustment of vancomycin to prevent nephrotoxicity.
OBJECTIVE
To determine the cost-effectiveness of pharmacokinetic dosage adjustment of vancomycin to prevent nephrotoxicity. An analysis was performed for subpopulations of patients receiving nephrotoxic agents (aminoglycosides, amphotericin, and acyclovir), those in the intensive care unit, and those on the oncology service.


METHODS
Decision analysis was used to model the cost-effectiveness of pharmacokinetic dosage adjustment of vancomycin. The reference case was determined, in part, by a retrospective review of 200 patients randomly selected from our clinical pharmacology consultation service. Patients were aged 18 years or older and had received intravenous vancomycin for at least 48 hours, with at least two--one peak and one trough--vancomycin serum concentrations obtained during therapy. Results of published clinical trials were used to determine the probability of vancomycin-induced nephrotoxicity.


RESULTS
The mean cost of treating nephrotoxicity was 11,233 dollars at our institution. The mean cost for all patients was 25,166 dollars (sensitivity analysis 15,000-27,500 dollars)/nephrotoxic episode prevented. The subgroup analysis revealed a cost of 8,363 dollars (sensitivity analysis 4,368-10,500 dollars)/nephrotoxic episode prevented in intensive care patients, 5,000 dollars (sensitivity analysis 1,687-13,250 dollars ) in oncology patients, and a dominant strategy showing a cost savings of 5,564 dollars (sensitivity analysis 2,724-12,428 dollars) in those receiving concomitant nephrotoxins.


CONCLUSIONS
Although pharmacokinetic monitoring and dosage adjustment are effective methods for reducing the toxicity of many drugs, controversy exists regarding the necessity of such monitoring with vancomycin. Evaluation by decision analysis over a range of assumptions, varying probabilities, and costs reveals that pharmacokinetic monitoring and vancomycin dosage adjustment to prevent nephrotoxicity are not cost-effective for all patients. However, such dosage adjustment demonstrates cost-effectiveness for patients receiving concomitant nephrotoxins, intensive care patients, and probably oncology patients.
Department of Pharmacy, Upstate Medical University Hospital, Syracuse, New York 13210, USA.
William
W
Darko
Joseph J
JJ
Medicis
Adrienne
A
Smith
Roy
R
Guharoy
David E
DE
Lehmann
D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000191:economics* / Q000493:pharmacokinetics; D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D016903:Drug Monitoring / Q000191:economics; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007674:Kidney Diseases / Q000139:chemically induced / Q000191:economics* / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D018803:Models, Economic; D016522:Oncology Service, Hospital; D012189:Retrospective Studies; D014640:Vancomycin / Q000008:administration & dosage* / Q000009:adverse effects / Q000191:economics* / Q000493:pharmacokinetics
D000900:Anti-Bacterial Agents; D014640:Vancomycin