Once-daily versus multiple-daily gentamicin in empirical antibiotic therapy of febrile neutropenia following intensive chemotherapy

Extended-interval aminoglycoside therapy for adult patients with febrile neutropenia: a systematic review

BACKGROUND

Although the efficacy and toxicity of extended-interval (once-daily) aminoglycoside regimens is well established for immunocompetent patients, there is clinical concern about using this regimen for patients with neutropenia.

OBJECTIVE

To summarize and evaluate the literature reporting the clinical efficacy and safety of extended-interval aminoglycosides therapy in adults with febrile neutropenia.

METHODS

A literature search was conducted within PubMed, Embase, and the Cochrane Database of Systematic Reviews to identify studies assessing the use of extended-interval aminoglycosides for treating febrile neutropenia in adults. Articles were categorized by quality of evidence, according to the rating scale of the US Preventive Services Task Force.

RESULTS

TEN ARTICLES WERE IDENTIFIED: 5 with level I evidence, 1 with level II-2 evidence, and 4 with level III evidence. Review of the 5 studies with level I evidence (all open-label randomized controlled trials), which compared extended-interval dosing with multiple-daily dosing strategies, revealed no evidence to suggest superiority of one regimen over the other in terms of clinical outcomes. In the study with level II-2 evidence (a prospective comparative trial), the response rate was better in the extended-interval group than in the standard-therapy group. Two of the studies with level III evidence (both prospective noncomparative trials) also had acceptable response rates to extended-interval aminoglycoside therapy, with minimal associated nephrotoxicity. In this review, no major differences in rates of nephrotoxicity or ototoxicity were seen between the 2 dosing regimens.

CONCLUSIONS

The use of extended-interval dosing for aminoglycosides, in combination with other recommended antibiotic therapy, is an effective and safe management strategy for immunocompromised patients with febrile neutropenia. In this population, the clinical efficacy and safety of extended-interval dosing does not appear to differ from those of standard dosing. Whether routine or selective pharmacokinetic monitoring in this patient subpopulation leads to improvements in outcomes is yet to be determined.

An evaluation of amikacin nephrotoxicity in the hematology/oncology population

Amikacin is an aminoglycoside commonly used to provide empirical double gram-negative treatment for febrile neutropenia and other suspected infections. Strategies of extended-interval and conventional dosing have been utilized extensively in the general medical population; however, data are lacking to support a dosing strategy in the hematology/oncology population. To evaluate amikacin-associated nephrotoxicity in an adult hematology/oncology population, a prospective, randomized, open-label trial was conducted at a university-affiliated medical center. Forty patients with a diagnosis consistent with a hematologic/oncologic disorder that required treatment with an aminoglycoside were randomized to either conventional or extended-interval amikacin. The occurrence of nephrotoxicity by means of an increase in serum creatinine and evaluation of efficacy via amikacin serum concentrations with respective pathogens were assessed. The occurrence of nephrotoxicity was similar between the conventional and extended-interval groups, at 10% and 5%, respectively (P = 1.00). Six patients in the conventional group had a positive culture, compared with none in the extended-interval group (P = 0.002). The occurrence of nephrotoxicity was similar between the two dosing regimens, but the distribution of risk factors was variable between the two groups. Efficacy could not be assessed.

The effect of vecuronium is enhanced by a large rather than a modest dose of gentamicin as compared with no preoperative gentamicin

We compared the effect of two doses of gentamicin versus no gentamicin (NG) given before surgery on the neuromuscular relaxant effect of vecuronium. Seventy patients (intraabdominal procedures) were randomly allocated to receive preoperative large-dose (4 mg/kg) gentamicin (LD), a modest dose (1.2 mg/kg) of gentamicin (MD), or NG. No more than one dose of gentamicin was given before the vecuronium administration. Serum gentamicin levels, the time for 25% recovery of the first twitch in the train-of-four after a bolus of vecuronium, and the time from cessation of the vecuronium infusion to extubation of the trachea were estimated. Serum gentamicin levels were higher (P < 0.001) for LD than MD. The time for 25% recovery of the first twitch after the vecuronium bolus was slightly longer with LD than MD (P = 0.06) and longer in LD than NG (P = 0.001) (42.9 +/- 23.6 min versus 36.2 +/- 17 min and 27.4 +/- 9 min, respectively). The time to extubation was similar with LD and MD and longer for LD than NG (P = 0.008) (34.7 +/- 19.2 min versus 27.4 +/- 19.3 min and 19.4 +/- 10.1 min, respectively). The differences in these times were insignificant between MD and NG. Gentamicin administered as a LD rather than MD enhanced the neuromuscular blockade of vecuronium as compared with NG given before surgery.

IMPLICATIONS

We demonstrated that the neuromuscular relaxant effect of vecuronium is enhanced by a large (4 mg/kg) rather than a modest (1.2 mg/kg) dose of gentamicin as compared with no gentamicin given before surgery.

Pitfalls associated with commonly used methods for pharmacoeconomic analyses

Demonstrating the economic value of treatment has become an important objective of many clinical trials. Awareness of the limitations of the methods used in pharmacoeconomic studies of infectious diseases will help in understanding why improved methods are needed to adequately describe the costs associated with infectious episodes. Current analyses generally consider three levels of cost and use three methods to determine costs associated with an infectious episode. However, these costs and the methods for obtaining them may not be appropriate in all studies. Future pharmacoeconomic research needs to adhere to established principles but embrace new methodologies to improve the validity and usefulness of these studies.