Two-point method for determination of aminoglycoside pharmacokinetics: theoretical and practical considerations

A method is described that utilizes any two serum concentrations obtained during a multiple dosage regimen to estimate aminoglycoside pharmacokinetics. The accuracy of this method was tested theoretically using simulated patient data. In addition, the ability of this method to estimate gentamicin pharmacokinetics and predict serum gentamicin concentrations (SGC) in individual patients was evaluated and compared with the method of Sawchuk and Zaske. Based on the theoretical and patient data evaluations, reasonably accurate pharmacokinetic parameters were derived by the present method, especially when a pair of peak and trough SGC were utilized. In addition, the prediction error of this two-point fitting method (using pairs of peak-trough SGC) was not significantly different from that of the Sawchuk-Zaske method. These results indicate that the present two-point method (when using a pair of peak-trough SGC) provides a convenient and useful approach in individualization of aminoglycoside therapy in patients.