A Practical Alternative to Conventional Aminoglycoside Dosing Methods

Abstract

OBJECTIVE:

One-compartment pharmacokinetic equations are adequate to perform clinical dosing adjustments for aminoglycoside monitoring. This article describes the Fuller-Goldman (FG) method, an alternative method of aminoglycoside dosage adjustment after serum concentrations have been obtained. The FG method uses pharmacokinetic principles, but does not use standard pharmacokinetic equations (SPE) for aminoglycoside dosage adjustment. A comparison of the FG method to SPE is also presented.

DATA SOURCES:

Information was obtained from pharmacokinetic textbooks and references using basic pharmacokinetic concepts. Forty sets of peak and trough serum drug concentrations were randomly chosen, retrospectively, from routine pharmacokinetic service data. All of the patients were men with a variety of infectious diseases and cared for on general surgical and medical floors, intensive care units, and a spinal cord injury unit.

STUDY SELECTION:

No studies have previously been published using this dosing method.

DATA EXTRACTION:

Peak and trough data were extracted from routine pharmacokinetic monitoring forms kept by the coordinator of the Pharmacokinetic Monitoring Service at the Department of Veterans Affairs Medical Center.

DATA SYNTHESIS:

The FG method is characterized by assumptions and limitations similar to those of standard pharmacokinetic dosing methods. Forty sets of data were evaluated using both the FG method and SPE. These data were analyzed using mean percent differences of projected dosages and projected half-lives (t¹/2s) as measures of the average magnitude of the discrepancy between the two methods. Ninety-five percent confidence intervals for mean percent differences also are provided.

CONCLUSIONS:

The FG method overestimated by 10.18 percent the dosage recommendations of the SPE method. This method also underestimated t¹/2 by 2.96 percent, compared with SPE. The FG method is a viable alternative aminoglycoside dosing technique that requires one to use learned pharmacokinetic concepts.