Reassessment of recommended imipenem doses in febrile neutropenic patients with hematological malignancies

Abstract

Imipenem plasma concentrations were analyzed in 57 febrile neutropenic patients using the NONMEM program. The recommended 2-g/day regimen achieved coverage of the most common bacteria (MIC(90) = 1 mg/liter) during the whole dosing interval in only 53% of patients. This goal was achieved in 90% of patients with 3 g/day.

FIG. 1.

Percentage of simulated patients with different GFR levels in whom imipenem plasma concentrations covered the MIC₉₀ of the most frequent pathogens (i.e., 1 mg/liter) over the whole dosing interval. The vertical dotted line indicates the standard GFR at 100 ml/min. (A) Different dosing schedules infused over 30 min: 1,000 mg every 6 h (thick line), 750 mg every 6 h (plain line), 500 mg every 6 h (dashed line), and 250 mg every 6 h (dotted line). (B) Different dosing schedules of a 3-g daily dose infused over 30 min are represented: 1,000 mg every 8 h (thick line), 750 mg every 6 h (plain line), and 500 mg every 4 h (dashed line). (C) Different infusion times of a 750-mg every 6 h dosing schedule are represented: 30 min (plain line), 60 min (dashed line), and 120 min (dotted line).