Evaluation of imipenem 1.5 g daily in febrile patients with short duration neutropenia after chemotherapy for non-leukemic hematologic malignancies and solid tumors: personal experience and review of the literature.

ABSTRACT

Numerous studies have demonstrated efficacy of imipenem-cilastatin, 50 mg/kg/day, as first line therapy in febrile patients with neutropenia of short duration consecutive to cytostatic chemotherapy. However, only two studies used low dosage of this antibiotic as 1.5 g/day, in prospective, double blind, randomized clinical trials, in this indication. Efficacy and tolerability of imipenem-cilastatin 0.5 g three times daily IV in 30-min infusions, as first-line empiric therapy, were retrospectively evaluated in our hematological unit. From January 1996 to September 2000, 30 neutropenic patients (12 females) with 45 febrile episodes were included. Median age was 57.5 years (31-75). Twenty-four of them had lymphomas, 4 solid tumors and 2 myelomas. There were 13 clinically documented infections, (CD, 28.8%), 16 microbiologically documented infections, (MD, 35.6%) and 16 febrile episodes corresponding to fever of unknown origin, (FUO, 35.6%). The median neutrophils count on nadir (n = 44), was 67/mm3 (8-369). The median duration of neutropenia was 5 days (3-15). Bacteremia was observed in 10 patients, urinary tract infection in 3 patients. The most frequently isolated microorganism was Escherichia coli. The overall success rate of the first line therapy was 66.7%. Adverse events were observed in 11.1% of the patients without necessity to stop treatment. The MD infections showed a lower rate of success compared with CD infections and FUO. These data were in accordance with the previous studies. The importance of number of microorganisms (p = 0.007) and of infected sites (p = 0.01) appeared as prognostic factors (univariate analysis). Although imipenem-cilastatin has been used in numerous studies as empiric broad-spectrum antibiotic therapy in the treatment of febrile neutropenic cancer patients, the exact dosage of this antibiotic is still not standardized. However, utilization of this antibiotic in monotherapy at low dosage seems to us to be safe and effective as usual dosage in the antimicrobial treatment ofthe febrile patients with post chemotherapy neutropenia of short duration.