Standardized gentamicin dosing enhances peak serum concentrations

The objectives of this study were to determine if a standardized gentamicin dosing protocol would improve clinical effectiveness, yield higher peak serum concentrations, and improve the success rate of attaining peaks in the desired range when compared with empiric dosing practices used by prescribers. The study was conducted as a before-after program effectiveness evaluation in non-critically ill patients, aged 16-65 y with stable renal function, who were prescribed gentamicin. A standardized dose of 2 mg/kg (ideal or adjusted weight) was administered intravenously every 12 h in the intervention phase. Response to therapy (time to defervescence, white cell count, reinstitution of antibiotic therapy), serum concentrations (peaks > 10 mumol/L (5.6 mg/L) and troughs < 4 mumol/L (2.2 mg/L)), and toxicity were monitored in both groups. Thirty-four consecutive patients were enrolled into the control phase and an equal number into the intervention phase. Surgical patients comprised the majority of the study population. Desired peak concentrations were attained in 97% of intervention vs. 59% of control patients (p < 0.001). Mean peak serum concentrations were higher in the intervention phase than in the control phase, 16.1 mumol/L vs. 11.2 mumol/L (p < 0.001), respectively. Median time to become afebrile trended toward a statistical decrease in the intervention as compared to the control group, 3 vs. 5 d (p = 0.076), respectively. There was no significant difference in clinical effectiveness nor in the occurrence of nephro- or ototoxicity. Continued evaluation of this dosing protocol is warranted.