Is there a rationale for the continuous infusion of cefepime? A multidisciplinary approach

Cefepime Dosing Requirements in Elderly Patients Attended in the Emergency Rooms

Objective

This study aimed to assess the probability of reaching an adequate pharmacokinetic/pharmacodynamic (pK/pD) index for different cefepime dosages in frail patients with bacteremia treated in the emergency room.

Methods

Simulation study based on Gram-negative bacterial strains that cause bacteremia. The probability of reaching a time above the minimum inhibitory concentration (MIC) at 50% and 100% dosing intervals (fT > 50 and fT > 80% MIC) was assessed for two different renal clearance intervals.

Results

One hundred twenty nine strains were collected, the predominant species being Escherichia coli (n = 83 [64.3%]). In patients with a ClCr of 30 mL/min, an fT > 50% MIC was reached in more than 90% of the simulations. However, a dose of at least 1 g every 12 h must be administered to reach an fT > 80% MIC. In patients with a ClCr of 30–60 mL/min, the probability of reaching an fT > 50% MIC was higher than 90% with doses of 1 g every 8 h or more, but this value was not reached in > 90% simulations for any of the doses tested in this study.

Conclusions

Standard cefepime dosing can reach an adequate PK/PD index in frail patients. Nevertheless, a high dose or extended infusion is necessary to reach an fT > 80% MIC in patients with a ClCr > 60 mL/min.

The safety of cefepime in the treatment of infection

BACKGROUND

Cefepime is a fourth-generation cephalosporin usually reserved for treating severe nosocomial pneumonia, as well as empirical treatment of febrile neutropenia, uncomplicated and complicated urinary tract infections, uncomplicated skin and skin structure infections, and complicated intra-abdominal infections.

OBJECTIVE

Since reports of neurotoxic effects and of an all-cause mortality higher with cefepime than with comparators have created some concerns regarding its safety, this paper reviews data available in the PubMed database up to December 2007 on cefepime safety.

METHODS

Literature data from PubMed obtained by combining cefepime and safety, or cefepime and clinical trials, were examined.

RESULTS/CONCLUSIONS

Caution in the use of cefepime should be adopted until new evidence on cefepime safety is available.

Development of breakpoints of cephems for intraabdominal infections based on pharmacokinetics and pharmacodynamics in the peritoneal fluid of patients

We developed breakpoints for cephem antibacterial agents for intraabdominal infections based on pharmacokinetics (PK) and pharmacodynamics (PD) at the target site. Cefepime (CFPM), cefotiam (CTM), cefozopran (CZOP), and flomoxef (FMOX) were each administered to 8-10 patients before abdominal surgery, and venous blood and peritoneal fluid (PF) samples were obtained. The drug concentrations in plasma and PF were determined and analyzed using population pharmacokinetic modeling. Using the pharmacokinetic model parameters, a Monte Carlo simulation was conducted to estimate the probabilities of attaining the bacteriostatic and bactericidal targets (40% and 70% of the time above the minimum inhibitory concentration (T > MIC), respectively) in PF. The bacteriostatic and bactericidal breakpoints were determined as the highest MIC values at which the bacteriostatic and bactericidal probabilities in PF were > or =80%, which values varied with drug and dosing regimen. Site-specific PK-PD-based breakpoints for CFPM, CTM, CZOP, and FMOX are proposed, and should help us to select appropriate cephems and design their dosing regimens for intraabdominal infections.

Approaches to the Treatment of Initial Pseudomonas aeruginosa Infection in Children Who Have Cystic Fibrosis

Pseudomonas aeruginosa remains an important cause of pulmonary disease in patients who have cystic fibrosis. The development of antimicrobial therapy directed against this organism has resulted in the preservation of lung function and improved longevity. Efficacy has been demonstrated with agents administered via parenteral, inhaled, and oral routes. The optimal antibiotic regimen remains unclear. There is an active effort to use randomized, controlled clinical trials to rigorously test effective antibiotic for the eradication of P aeruginosa in young children or at least to delay the establishment of chronic infection.

A novel extended-spectrum TEM-type beta-lactamase, TEM-138, from Salmonella enterica serovar Infantis

A novel natural TEM beta-lactamase with extended-spectrum activity, TEM-138, was identified in a ceftazidime-resistant clinical isolate of Salmonella enterica serovar Infantis. Compared to TEM-1, TEM-138 contains the following mutations: E104K, N175I, and G238S. The bla(TEM-138) gene was located on a 50-kb transferable plasmid. Expression studies with Escherichia coli revealed efficient ceftazidimase and cefotaximase activities for TEM-138.

Trough serum concentrations of β-lactam antibiotics in cancer patients: inappropriateness of conventional schedules to pharmacokinetic/pharmacodynamic properties of β-lactams

Serum concentrations of beta-lactams that continuously exceed the minimum inhibitory concentration may improve therapeutic outcomes for immunosuppressed patients. The trough serum levels of ceftazidime (CAZ), cefepime (FEP) or imipenem (IMP) were prospectively determined on days 1 and 3 of treatment in cancer patients. Seventy-eight episodes of suspected infection were analysed. Trough serum levels were higher than 4 mg/L in 62%, 24% and 0% of cases in the CAZ, FEP and IMP groups, respectively, and were higher than 20 mg/L in 24% of cases in the CAZ group compared with 0% both in the FEP and IMP groups. For suspected infectious episodes in cancer patients, the traditional intermittent regimen of beta-lactams does not appear to be appropriate for the pharmacokinetic/pharmacodynamic properties of these antibiotics.

[Monitoring of antibiotic treatment of patient with a severe bacterial infection]

OBJECTIVES

To provide a summary of useful up-to-date knowledge regarding experimental and clinical bacteriology, pharmacokinetics and pharmacodynamics in order to optimise efficacy of antibiotic treatment of hospital patients with serious bacterial infections.

DATA SOURCES

Record of references from national and international journals in Medline.

STUDY SELECTION

Extraction of the most relevant theoretical and practical data from studies published over the last 5 years.

DATA SYNTHESIS

Changes in resistance to antibiotics, as well as the limited number of new antibacterial drugs available and the cost of therapeutic failure all militate in favour of a more elaborate approach to therapeutic strategies involving antibiotics, particularly regarding hospitalised patients. The efficacy of antibiotic therapy can be optimised through the utilization of bacteriological, pharmacokinetic and pharmacodynamic data, thereby increasing the likelihood of a successful outcome. While the antibiogram constitutes the fundamental analytical tool for evaluating the activity of antibiotics, the minimum inhibitory concentration (MIC) is of value in selecting appropriate drugs and dosages, particularly for bacterial strains having lower susceptibility. Screening for genes of resistance to antibiotics provides more accurate analysis of bacterial resistance. In recent years, the efficacy of antibiotics has been improved through the use of a number of pharmacodynamic parameters: inhibitory quotient (IQ), area under the serum concentration-time curve to MIC ratio (AUC/MIC) and the time the serum concentration is greater than the MIC (T > MIC). In standard practice, data readily available to the clinician comprise the MIC and serum antibiotic concentrations. There is some discussion concerning optimisation of antibiotic efficacy through the use of these parameters.

CONCLUSION

Close collaboration between clinicians and microbiologists results in improved quality of antibiotic therapy and better management of antibiotics.