Pharmacoeconomics of continuous versus intermittent infusion of piperacillin-tazobactam for the treatment of complicated intraabdominal infection

Optimizing Betalactam Clinical Response by Using a Continuous Infusion: A Comprehensive Review

INTRODUCTION

Antimicrobial resistance is a major healthcare issue responsible for a large number of deaths. Many reviews identified that PKPD data are in favor of the use of continuous infusion, and we wanted to review clinical data results in order to optimize our clinical practice.

METHODOLOGY

We reviewed Medline for existing literature comparing continuous or extended infusion to intermittent infusion of betalactams.

RESULTS

In clinical studies, continuous infusion is as good as intermittent infusion. In the subset group of critically ill patients or those with an infection due to an organism with high MIC, a continuous infusion was associated with better clinical response.

CONCLUSIONS

Clinical data appear to confirm those of PK/PD to use a continuous infusion in severely ill patients or those infected by an organism with an elevated MIC, as it is associated with higher survival rates. In other cases, it may allow for a decrease in antibiotic daily dosage, thereby contributing to a decrease in overall costs.

Simplifying Piperacillin/Tazobactam Dosing: Pharmacodynamics of Utilizing Only 4.5 or 3.375 g Doses for Patients With Normal and Impaired Renal Function

OBJECTIVES

To evaluate the pharmacodynamic exposure of piperacillin/tazobactam across the renal function range using 4.5 or 3.375 g dosing regimens.

METHODS

A 5000-patient Monte Carlo simulation was conducted to determine the probability of achieving 50% free time above the minimum inhibitory concentration ( fT > MIC) for piperacillin. Proposed regimens, using solely 4.5 or 3.375 g strengths, were compared with regimens listed in piperacillin/tazobactam prescribing information over creatinine clearance (CrCl) ranges of 120 mL/min to hemodialysis. The probability of target attainment (PTA) at MICs ≤ 16 μg/mL was compared between proposed and standard regimens.

RESULTS

At CrCl 41 to 120 mL/min, prolonged infusions of 4.5 g (3 hours) and 3.375 g (4 hours) every 6 hours resulted in ≥95% PTA versus ≥76% for standard regimens (0.5 hour). At CrCl 20 to 40 mL/min, 4.5 and 3.375 g every 8 hours as prolonged infusions achieved slightly higher PTA (≥98%) versus standard regimens (≥93%). Similarly, PTA achieved with prolonged infusions of 4.5 and 3.375 g every 12 hours (≥93%) was comparable with those of standard regimens (≥91%) at CrCl 1 to 19 mL/min. In hemodialysis, 100% PTA was achieved with prolonged infusion regimens.

CONCLUSION

Piperacillin/tazobactam regimens designed around the 4.5 or 3.375 g dose and prolonged infusions provided similar or better PTA at MICs ≤ 16 μg/mL compared with standard regimens. These observations may support the stocking and use of a single piperacillin/tazobactam strength to simplify dosing.

Clinical outcomes with alternative dosing strategies for piperacillin/tazobactam: a systematic review and meta-analysis

Objectives

A better dosing strategy can improve clinical outcomes for patients. We sought to compare the extended or continuous infusion with conventional intermittent infusion of piperacillin/tazobactam, investigating which approach is better and worthy of recommendation for clinical use.

Methods

Articles were gathered from PubMed, Web of Science, ProQuest, Science Direct, Cochrane, two Chinese literature databases (CNKI, Wan Fang Data) and related ICAAC and ACCP conferences. Randomized controlled and observational studies that compared extended or continuous infusion with conventional intermittent infusion of piperacillin/tazobactam were identified from the databases above and analyzed. Two reviewers independently extracted and investigated the data. A meta-analysis was performed using Revman 5.2 software. The quality of each study was assessed. Sensitivity analysis and publication bias were evaluated.

Results

Five randomized controlled trials and nine observational studies were included in this study. All included studies had high quality and no publication bias was found. Compared to the conventional intermittent infusion approach, the extended or continuous infusion group had a significantly higher clinical cure rate (OR 1.88, 95% CI 1.29-2.73, P = 0.0009) and a lower mortality rate (OR 0.67, 95% CI 0.50-0.89, P = 0.005). No statistical difference was observed for bacteriologic cure (OR 1.40, 95% CI 0.82-2.37, P = 0.22) between the two dosing regimens. The sensitivity analysis showed the results were stable.

Conclusions

Our systematic review and meta-analysis suggested that the extended or continuous infusion strategy of piperacillin/tazobactam should be recommended for clinical use considering its higher clinical cure rate and lower mortality rate in comparison with conventional intermittent strategy. Data from this study could be extrapolated for other β-lactam antimicrobials. Therefore, this dosing strategy could be considered in clinical practice.

Engaging Pharmacy Students, Residents, and Fellows in Antimicrobial Stewardship

Antimicrobial stewardship programs are mainly established by infectious diseases physicians and infectious diseases-trained clinical pharmacists with the goal of optimizing patients' outcomes while halting antimicrobial resistance, decreasing adverse events, and controlling health care cost. The role of the infectious diseases-trained clinical pharmacist in antimicrobial stewardship is well established; however, there are not enough formally trained pharmacists to assume the challenging responsibilities of the steward coordinator. The purpose of this article was to review the available literature and resources and propose a model to engage introductory pharmacy practice experience students, advanced pharmacy practice experience students, postgraduate year (PGY) 1 pharmacy residents, PGY2 infectious diseases pharmacy residents, and PGY2 or PGY3 infectious diseases pharmacy fellows in antimicrobial stewardship. Further studies are needed to assess and document the impact of pharmacy students and postgraduate trainees on antimicrobial stewardship programs.

Continuous versus intermittent infusions of antibiotics for the treatment of severe acute infections

BACKGROUND

Intravenous broad-spectrum antibiotics are indicated for the treatment of severe infections. However, the emergence of infections caused by multi-drug resistant organisms in conjunction with a lack of novel antibiotics has prompted the investigation of alternative dosing strategies to improve clinical efficacy and tolerability. To optimise pharmacokinetic and pharmacodynamic antibiotic parameters, continuous antibiotic infusions have been compared to traditional intermittent antibiotic infusions.

OBJECTIVES

To compare the clinical efficacy and safety of continuous intravenous administration of concentration-dependent and time-dependent antibiotics to traditional intermittent intravenous administration in adults with severe acute bacterial infections.

SEARCH METHODS

The following electronic databases were searched in September 2012: The Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials (The Cochrane Library), MEDLINE (OvidSP), EMBASE (OvidSP), CINAHL, ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Conference Proceedings Citation Index-Science (CPCI-S). The reference lists of all relevant material, the Internet and the trials registry www.clinicaltrials.gov for completed and ongoing trials were also searched.

SELECTION CRITERIA

Randomized controlled trials in adults with a bacterial infection requiring intravenous antibiotic therapy comparing continuous versus intermittent infusions of antibiotics were included. Both time-dependent and concentration-dependent antibiotics were considered.

DATA COLLECTION AND ANALYSIS

Three independent authors performed data extraction for the included studies. All data was cross-checked and disagreements resolved by consensus. An intention to treat analysis was conducted using a random-effects model.

MAIN RESULTS

Twenty-nine studies met inclusion criteria with a combined total of over 1,600 patients. The majority of included studies were judged to be at unclear or high risk of bias with regard to randomisation sequence generation, allocation concealment, blinding, management of incomplete outcome data, selective outcome reporting, and other potential threats to validity. No studies were judged to be at low risk of bias for all methodological quality items assessed. There were no differences in all-cause mortality (n=1241, RR 0.89, 95% CI 0.67 - 1.20, p=0.45), infection recurrence (n=398, RR 1.22, 95% CI 0.35 - 4.19, p=0.76), clinical cure (n=975, RR 1.00, 95% CI 0.93 - 1.08, p=0.98), and superinfection post-therapy (n=813, RR 1.08, 95% CI 0.60 - 1.94, p=0.79). There were no differences in safety outcomes including adverse events (n=575, RR 1.02, 95% CI 0.94 - 1.12, p=0.63), serious adverse events (n=871, RR 1.36, 95% CI 0.80 - 2.30, p=0.26), and withdrawal due to adverse events (n=871, RR 2.03, 95% CI 0.52 - 7.95, p=0.31). A difference was observed in the subgroup analyses of clinical cure in septic versus non-septic patients, where intermittent antibiotic infusions were favoured for clinical cure in septic patients. However, this effect was not consistent between random-effects and fixed-effects analyses. No differences were found in sensitivity analyses conducted.

AUTHORS' CONCLUSIONS

There were no differences in mortality, infection recurrence, clinical cure, superinfection post-therapy, and safety outcomes when comparing continuous infusions of intravenous antibiotics to traditional intermittent infusions of antibiotics. However, the wide confidence intervals suggest that beneficial or harmful effects cannot be ruled out for all outcomes. Therefore, the current evidence is insufficient to recommend the widespread adoption of continuous infusion antibiotics in the place of intermittent infusions of antibiotics. Further large prospective randomised trials, with consistent and complete reporting of clinical outcome measures, conducted with concurrent pharmacokinetic and pharmacodynamic studies in special populations are required to determine whether adoption of continuous antibiotic infusions is warranted in specific circumstances.

Comparison of the Pharmacokinetics of Piperacillin and Sulbactam during Intermittent and Continuous Intravenous Infusion

BACKGROUND

The antibacterial effect of piperacillin/sulbactam depends on the time of drug concentration above the minimal inhibitory concentration (MIC). Therefore, continuous infusion (CI) may be a more rational approach than standard intermittent short-term infusion (SI). The study investigated whether CI achieves effective drug concentrations comparable with SI.

METHODS

Seven intensive care unit patients received either piperacillin/sulbactam as 4/1 g intravenous infusion over 15-20 min every 8 h or as 4/1 g intravenous loading dose (15-20 min) followed by 8/2 g intravenous CI per 24 h. After 2 days, regimes were crossed over.

RESULTS

Pharmacokinetic parameters (mean +/- SD) for SI piperacillin/sulbactam were: (1) peak serum concentration: piperacillin 231 +/- 66 mg/l, sulbactam 53.1 +/- 15.0 mg/l; (2) minimum serum concentration: piperacillin 11.5 +/- 14.8 mg/l, sulbactam 4.2 +/- 3.5 mg/l; (3) clearance: piperacillin 197 +/- 72 ml/min (CI 269 +/- 123 ml/min), sulbactam 167 +/- 61 ml/min (CI 212 +/- 109 ml/min); (4) half-life: piperacillin 2.4 +/- 1.2 h, sulbactam 3.1 +/- 1.6 h. Steady-state concentrations during CI were 25.5 +/- 14.5 mg/l for piperacillin and 8.0 +/- 3.7 mg/l for sulbactam. Average serum concentrations were comparable in both regimens.

CONCLUSION

A large German survey demonstrated that approximately 89% of Pseudomonas aerugionsa have an MIC < or =16 mg/l and approximately 82% have an MIC < or =8 mg/l. According to this threshold, appropriate anti-bacterial concentrations of piperacillin/sulbactam were achievable with CI. CI dosing has the additional advantage that less drug is necessary. Further prospective studies are warranted to compare the clinical efficacy of CI and SI regimens in bacterial infections.

Intra-abdominal infections

PURPOSE OF REVIEW

The aim of this article is to outline developments in the three cornerstones of treatment of intra-abdominal infections during critical illness: source control; antimicrobial therapy; and mitigation of deranged immune and coagulation responses.

RECENT FINDINGS

Although adequate source control remains the goal of mechanical management of intra-abdominal infections, neither planned re-laparotomy nor open-abdomen management appears to offer a survival benefit as compared with on-demand re-laparotomy. Novel approaches to restoration of a functional gastrointestinal tract have emerged as alternatives to more invasive surgery. A persistent increase in the prevalence of intra-abdominal infections caused by multidrug resistant pathogens has led researchers to investigate shorter-course antimicrobial therapy and other antibiotic administration strategies with encouraging initial results. Therapy with recombinant human activated protein C should now be considered for patients with severe abdominal sepsis associated with a high risk of death.

SUMMARY

Because randomized controlled trials of intra-abdominal infections involve critically ill patients infrequently, only limited evidence-based recommendations regarding the management of these patients may be drawn. Therapy should focus above all else on timely obtainment of adequate source control, in conjunction with judicious use of antimicrobial therapy dictated by individual patient risk factors for infection with multidrug resistant pathogens.

Piperacillin-tazobactam: a beta-lactam/beta-lactamase inhibitor combination

Piperacillin-tazobactam is a beta-lactam/beta-lactamase inhibitor combination with a broad spectrum of antibacterial activity that includes Gram-positive and -negative aerobic and anaerobic bacteria. Piperacillin-tazobactam retains its in vitro activity against broad-spectrum beta-lactamase-producing and some extended-spectrum beta-lactamase-producing Enterobacteriaceae, but not against isolates of Gram-negative bacilli harboring AmpC beta-lactamases. Piperacillin-tazobactam has recently been reformulated to include ethylenediaminetetraacetic acid and sodium citrate; this new formulation has been shown to be compatible in vitro with the two aminoglycosides, gentamicin and amikacin, allowing for simultaneous Y-site infusion, but not with tobramycin. Multicenter, randomized, double-blinded clinical trials have demonstrated piperacillin-tazobactam to be as clinically effective as relevant comparator antibiotics. Clinical trials have demonstrated piperacillin-tazobactam to be effective for the treatment of patients with intra-abdominal infections, skin and soft tissue infections, lower respiratory tract infections, complicated urinary tract infections, gynecological infections and more recently, febrile neutropenia. Piperacillin-tazobactam has an excellent safety and tolerability profile and continues to be a reliable option for the empiric treatment of moderate-to-severe infections in hospitalized patients.

Randomized, open-label, comparative study of piperacillin-tazobactam administered by continuous infusion versus intermittent infusion for treatment of hospitalized patients with complicated intra-abdominal infection

The purpose of this randomized, multicenter, open-label study was to compare the continuous infusion of piperacillin-tazobactam with the standard intermittent infusion in 262 hospitalized patients with complicated intra-abdominal infections. Within 1 day of surgical intervention, eligible patients were randomized (1:1) to piperacillin-tazobactam 12 g/1.5 g administered continuously over 24 h or 3 g/0.375 g administered over 30 min intermittently every 6 h for 4 to 14 days. The demographics of the patients in the groups were similar, with a median APACHE II score of 7 and a median length of hospitalization of 7 days. Among 167 clinically evaluable patients, 86.4% and 88.4% of the patients treated with the continuous infusion and the intermittent infusion, respectively, were clinically cured or improved at the test-of-cure visit (P = 0.817). Bacteriological success was observed in 83.9% and 87.9% of patients (P = 0.597) in the two groups, respectively, and no differences in bacteriological response by pathogen were noted. Defervesence and white blood cell count normalization occurred in the majority of patients within 3 days and were similar between patients receiving the continuous infusion and those receiving the intermittent infusion. Drug-related adverse events were generally mild and were reported in similar numbers of patients in each arm of the trial. The results of this study support continuous infusion as a safe and reasonable alternate mode of administration of piperacillin-tazobactam for the treatment of complicated intra-abdominal infection.

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