Low-dose continuous-infusion ceftazidime monotherapy in low-risk febrile neutropenic patients

Effect of meropenem administration in extended infusion on the clinical outcome of febrile neutropenia: a retrospective observational study

OBJECTIVES

Information on the efficacy of extended meropenem administration in neutropenic patients is scarce. Our objective was to determine whether the administration of meropenem in a 4 h extended infusion (EI) leads to a better clinical outcome in patients with febrile neutropenia than the conventional short infusion (SI).

METHODS

This was a retrospective observational study. The subjects were neutropenic patients who presented with fever after receiving haematopoietic stem-cell transplantation or induction chemotherapy for acute myeloid leukaemia. The primary endpoint was the success of treatment after 5 days of meropenem therapy, defined as follows: the disappearance of fever leading to a maintained (≥ 24 h) feverless state; the resolution or improvement of the clinical signs and symptoms of infection; the absence of persistent or breakthrough bacteraemia; and no additional antibiotics prescribed because of an unsatisfactory clinical evolution.

RESULTS

Eighty-eight patients received meropenem (1 g/8 h) in SI and 76 received the same dose in EI. Treatment success on day 5 was superior in the EI group [52/76 (68.4%) versus 36/88 (40.9%); P<0.001]. Meropenem administered in EI was independently associated with success (OR 3.13, 95% CI 1.61-6.10). Fewer additional antibiotics were prescribed in the EI group during the first 5 days of treatment [20/76 (26.3%) versus 44/88 (50.0%); P=0.002]. Using Kaplan-Meier survival analysis a more prompt defervescence and a faster decrease in C-reactive protein concentration were observed in the EI group (P=0.021 and P=0.037, respectively). There were no significant differences in the length of hospital stay and in the mortality rate.

CONCLUSIONS

Meropenem administration in EI results in a better clinical outcome for febrile neutropenia episodes, with fewer additional antibiotics needed.

Management of febrile neutropenia in solid tumours and lymphomas using the Multinational Association for Supportive Care in Cancer (MASCC) risk index: feasibility and safety in routine clinical practice

GOALS OF WORK

Febrile neutropenia (FN) represents a spectrum of severity in which low-risk patients can be defined using the Multinational Association for Supportive Care in Cancer (MASCC) risk index. However, despite publication in 2000, there remains limited published literature to date to support the use of MASCC risk assessment in routine clinical practice and eligibility for early hospital discharge. In this study, we present our experience with the routine use of the MASCC risk index to determine the management of FN in our institution.

PATIENTS AND METHODS

Patients treated for solid tumours or lymphomas with low-risk FN (MASCC score >/ or =21) were eligible for oral antibiotics (ciprofloxacin plus either co-amoxiclav or doxycycline) and for early hospital discharge irrespective of first or subsequent episode. The primary outcome was rate of resolution of FN without serious medical complications (SMC). Secondary outcomes were the "success" of antibiotic therapy without treatment modifications, duration of hospitalisation and rate of readmissions.

RESULTS

A total of 100 FN episodes occurring in 83 patients were treated over a 6-month period. Ninety of these episodes were low-risk (90%), of which 75 received oral antibiotics (83.3%) and 3 (3.3%) experienced SMC, and the success rate was 94.5% [95% confidence interval (CI) 89.6-99.3%] in low-risk episodes. The median duration of hospitalisation was 2.5 days (25th centile: 1.0 day; 75th centile: 5.0 days) in low-risk compared to 6.5 days (25th centile: 5.3 days; 75th centile: 9.3 days) in high-risk episodes (p = 0.003); 2 days for low-risk episodes treated with oral antibiotics compared to 4 days for low-risk receiving intravenous antibiotics (p = 0.015). Positive predictive value for the MASCC index was 96.7% (95% CI 95.0-98.6%).

CONCLUSION

The MASCC risk index is both feasible and safe when used in standard clinical practice to guide the management of FN in patients with solid tumours and lymphomas. Patients predicted to have low risk can be managed safely with oral antibiotics and early hospital discharge.

Algunas reflexiones acerca de la administración de antibióticos betalactámicos en infusión continua

Numerous studies on continuous intravenous infusion of betalactam antibiotics have indicated that this could be a useful strategy for treating nosocomial infections as well as exacerbations of pulmonary infections in patients with cystic fibrosis and episodes of febrile neutropenia. From the pharmacodynamic viewpoint, betalactam antibiotics have a time-dependent behavior. Thus, the pharmacokinetic/pharmacodynamic index that best correlates with therapeutic efficacy appears to be the time during which free antibiotic concentrations remain above the minimum inhibitory concentration (MIC) of the infecting microorganism. Continuous infusion of betalactams successfully optimizes this pharmacokinetic/ pharmacodynamic index. Furthermore, some studies have shown that this therapeutic strategy may be favorable economically.

Continuous versus intermittent intravenous administration of antibacterials with time-dependent action: a systematic review of pharmacokinetic and pharmacodynamic parameters

We performed a systematic review of randomised clinical trials to evaluate the comparative pharmacokinetic and pharmacodynamic properties of the continuous versus intermittent mode of intravenous administration of various antibacterials. Data were identified from PubMed (January 1950 to January 2005), Current Contents, the Cochrane central register of controlled trials, and references from relevant articles and reviews. Seventeen randomised clinical trials comparing continuous with intermittent intravenous administration of the same antibacterial regimen and examining the pharmacokinetic and pharmacodynamic properties were included in this systematic review. We reviewed data regarding the clinical setting, number of participants, antibacterial agents and dosages used, as well as maximum serum concentration (Cmax), trough serum concentration (Cmin), steady-state or plateau serum concentration (Css), area under the concentration-time curve (AUC), time above the minimum inhibitory concentration (MIC) [T>MIC], AUC: MIC, elimination rate constant, elimination half-life, volume of distribution and systematic clearance. The mean Cmax of the intermittently administered antibacterials was higher compared with Css achieved by the continuous infusion of the same antibacterial in all eligible studies (Cmax was on average 5.5 times higher than Css, range 1.9-11.2). Css was on average 5.8 times higher than the Cmin of the intermittently administered antibacterials (range 1.2-15.6). In three of six studies the length of time that the drug concentration was above the MIC of the responsible pathogens was longer in patients receiving the antibacterials continuously. In conclusion, the reviewed data suggest that the continuous intravenous infusion of antibacterials with time-dependent bacterial killing seems to be superior than the intermittent intravenous administration, from a pharmacodynamic point of view, at least when treating bacteria with high MIC values for the studied antibacterials.

Continuous versus intermittent intravenous administration of antibiotics: a meta-analysis of randomised controlled trials

Intermittent intravenous administration of antibiotics is the first-line approach in the management of severe infections worldwide. However, the potential benefits of alternate modes of administration of antibiotics, including continuous intravenous infusion, deserve further evaluation. We did a meta-analysis of randomised controlled trials comparing continuous intravenous infusion with intermittent intravenous administration of the same antibiotic regimen. Nine randomised controlled trials studying beta-lactams, aminoglycosides, and vancomycin were included. Clinical failure was lower, although without statistical significance, in patients receiving continuous infusion of antibiotics (pooled OR 0.73, 95% CI 0.53-1.01); the difference was statistically significant in a subset of randomised controlled trials that used the same total daily antibiotic dose for both intervention arms (0.70, 0.50-0.98, fixed and random effects models). Regarding mortality and nephrotoxicity, no differences were found (mortality 0.89, 0.48-1.64; nephrotoxicity 0.91, 0.56-1.47). In conclusion, the data suggest that the administration of the same total antibiotic dose by continuous intravenous infusion may be more efficient, with regard to clinical effectiveness, compared with the intermittent mode. In an era of gradually increasing resistance among most pathogens, the potential advantages of continuous intravenous administration of antibiotics on several clinical outcomes should be further investigated.

Oral antibiotics with early hospital discharge compared with in-patient intravenous antibiotics for low-risk febrile neutropenia in patients with cancer: a prospective randomised controlled single centre study

Neutropenic sepsis remains a potentially life-threatening complication of anticancer chemotherapy. However, it is possible to identify patients who are at low risk for serious complications and for whom less-intensive, more-convenient treatment may be appropriate. The aim of this study was to assess the efficacy and safety of oral antibiotics in conjunction with early hospital discharge in comparison with standard in-patient intravenous antibiotics in patients with low-risk neutropenic fever. In all, 126 episodes of low-risk neutropenic fever occurred in 102 patients. Patients were randomised to receive either: an oral regimen of ciprofloxacin (750 mg 12 hourly) plus amoxicillin-clavulanate (675 mg 8 hourly) for a total of 5 days, or a standard intravenous regimen of gentamicin and tazocin (piperacillin/tazobactam) until hospital discharge. Patients randomised to oral antibiotics were eligible for discharge following 24 h of hospitalisation, if clinically stable and symptomatically improved. The efficacy of the two arms was similar: initial treatment was successful without antibiotic modification in 90% of episodes in the intravenous arm and 84.8% of episodes in the oral arm, P=0.55, absolute difference between the groups 5.2%; 95% confidence interval (CI) for the difference -7 to 17.3%. Only one episode in the oral arm was associated with significant clinical deterioration: this occurred within the initial in-patient assessment period. The median in-patient stay was 4 days in the intravenous arm (range 2-8) and 2 days in the oral arm (range 1-16 days), P&<0.0005. The reduction in hospital stay led to significant cost-savings in the oral arm. In conclusion, this study suggests that oral antibiotics in conjunction with early hospital discharge for patients who remain stable after a 24 h period of in-patient monitoring offers a feasible and cost-effective alternative to conventional management of low-risk neutropenic fever.

Pharmacokinetics and pharmacodynamics of piperacillin/tazobactam when administered by continuous infusion and intermittent dosing

BACKGROUND

Although intermittent bolus dosing is currently the standard of practice for many antimicrobial agents, beta-lactams exhibit time-dependent bacterial killing. Maximizing the time above the minimum inhibitory concentration (MIC) for a pathogen is the best pharmacodynamic predictor of efficacy. Use of a continuous infusion has been advocated for maximizing the time above the MIC compared with intermittent bolus dosing.

OBJECTIVE

This study compared the pharmacokinetics and pharmacodynamics of piperacillin/tazobactam when administered as an intermittent bolus versus a continuous infusion against clinical isolates of Pseudomonas aeruginosa and Klebsiella pneumoniae.

METHODS

Healthy volunteers were randomly assigned to receive piperacillin 3 g/ tazobactam 0.375 g q6h for 24 hours, piperacillin 6 g/tazobactam 0.75 g continuous infusion over 24 hours, and piperacillin 12 g/tazobactam 1.5 g continuous infusion over 24 hours. Five clinical isolates each of P aeruginosa and K pneumoniae were used for pharmacodynamic analyses.

RESULTS

Eleven healthy subjects (7 men, 4 women; mean +/- SD age, 28 +/- 4.7 years) were enrolled. Mean steady-state serum concentrations of piperacillin were 16.0 +/- 5.0 and 37.2 +/- 6.8 microg/mL with piperacillin 6 and 12 g, respectively. Piperacillin/tazobactam 13.5 g continuous infusion (piperacillin 12 g/tazobactam 1.5 g) was significantly more likely to produce a serum inhibitory titer > or = 1:2 against P aeruginosa at 24 hours than either the 6.75 g continuous infusion (piperacillin 6 g/tazobactam 0.75 g) or 3.375 g q6h (piperacillin 3 g/ tazobactam 0.375 g). There were no statistical differences against K pneumoniae between regimens. The median area under the inhibitory activity-time curve (AUIC) for the 13.5 g continuous infusion was higher than that for 3.375 g q6h and the 6.75 g continuous infusion against both P aeruginosa and Kpneumoniae (P < or = 0.007, 13.5 g continuous infusion and 3.375 g q6h vs 6.75 g continuous infusion against K pneumoniae). The percentage of subjects with an AUIC > or = 125 was higher with both 3.375 g q6h and the 13.5 g continuous infusion than with the 6.75 g continuous infusion against P aeruginosa and K pneumoniae (both, P < 0.001 vs 6.75 g continuous infusion against K pneumoniae).

CONCLUSIONS

Piperacillin 12 g/tazobactam 1.5 g continuous infusion consistently resulted in serum concentrations above the breakpoint for Enterobacteriaceae and many of the susceptible strains of P aeruginosa in this study in 11 healthy subjects. Randomized controlled clinical trials are warranted to determine the appropriate dose of piperacillin/tazobactam.

Temporary interruption of ceftazidime continuous infusion without reduction of activity: a computer-assisted simulation

Continuous infusion (CI) of ceftazidime has been demonstrated to add clinical advantages in the treatment of infection of neutropenic cancer patients, especially in the presence of gram-negative bacteremia. However, this particular administration route is not always feasible in this particular clinical setting because of the patient's need of additional care or drug administration. The aim of this study was to evaluate, through a computer-assisted simulation, the modifications of drug concentration in presence of a single or repeated 2-hour interruptions of CI ceftazidime in critically ill patients. Our analysis shows that a loading dose of 20 mg/kg, followed by a CI of 100/mg/kg/die, should be able to maintain efficacious plasma concentrations in all subjects, even when it is interrupted for a 2-hour period every 8 hours. Plasma concentrations after interruption should not fall below 8 microg/mL and for about 65-80% of time should reach levels equal to 5 times the MIC of the infecting pathogen. A 2-hour interruption of CI ceftazidime up to 3 times a day is likely to represent a safe and efficacious administration regimen that may enhance the management of the treatment of infectious complications in critically ill patients such as neutropenic cancer patients.

Continuous versus intermittent administration of ceftazidime in intensive care unit patients with nosocomial pneumonia

A prospective, randomized pilot study was undertaken to compare the efficacy of continuous versus intermittent ceftazidime in ICU patients with nosocomial pneumonia. Ceftazidime was administered either as a 3 g/day continuous infusion (CI) or an intermittent infusion (II) of 2 g every 8 h. In addition, all patients received concomitant once-daily tobramycin. The demographics of the evaluable patients (n = 35) were similar between the groups: age (years), CI 46 +/- 16, II 56 +/- 20; Apache score, CI 14 +/- 4, II 16 +/- 6; time (days) from admission to diagnosis, CI 9 +/- 6, II 9 +/- 6. Clinical efficacy, defined as cure/improvement was similar between groups [n (%), CI 16/17 (94), II 15/18 (83)], while microbiological response was also comparable [n (%), CI 10/13 (76), II 12/15 (80)]. Minimal inhibitory concentrations (MICs) for all isolates were measured throughout the treatment course; there was no development of resistance during therapy for either regimen. While limited clinical data exist, our results suggest that the use of ceftazidime by CI administration maintains clinical efficacy, optimizes the pharmacodynamic profile and uses less antibiotic compared with the standard 2 g every 8 h intermittent dosing regimen.