A randomized trial of ciprofloxacin plus azlocillin versus netilmicin plus azlocillin for the empirical treatment of fever in neutropenic patients

Ciprofloxacin vs an aminoglycoside in combination with a beta-lactam for the treatment of febrile neutropenia: a meta-analysis of randomized controlled trials

OBJECTIVE

To compare the effectiveness and toxicity of ciprofloxacin vs an aminoglycoside, both in combination with a beta-lactam, for the treatment of febrile neutropenia in the inpatient setting.

METHODS

For this meta-analysis of randomized controlled trials (RCTs) that compared the ciprofloxacin/beta-lactam combination vs an aminoglycoside/beta-lactam combination for the treatment of febrile neutropenia and reported data on effectiveness, mortality, and/or toxicity, we searched PubMed (1950-2004), Current Contents, Cochrane Central Register of Controlled Trials, and reference lists of retrieved articles, including review articles, as well as abstracts presented at international conferences. Data for 3 primary and 2 secondary outcomes were extracted by 2 investigators.

RESULTS

Eight RCTs were included in the analysis. Comparable or better outcomes were observed with the ciprofloxacin/beta-lactam combination vs an aminoglycoside/beta-lactam combination: clinical cure without modification of the initial regimen (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.00-1.74; P=.05), clinical cure in the subset of patients with documented Infections (OR, 1.56; 95% CI, 1.05-2.31; P=.03), all-cause mortality (OR, 0.85; 95% CI, 0.54-1.35; P=.49), withdrawal of the study drugs due to toxicity (OR, 0.87; 95% CI, 0.57-1.32; P-.51), and nephrotoxicity (OR, 0.30; 95% CI, 0.16-0.59; P<.001). The ciprofloxacin/beta-lactam combination was also associated with better clinical cure compared to the aminoglycoside/beta-actam combination in the subset of RCTs with non-low-risk patients (OR, 1.38; 95% CI, 1.01-1.88; P=-.04), as well as in the subset of studies that included the same beta-lactam in both treatment arms (OR, 1.47; 95% CI, 1.06-2.05; P=.02).

CONCLUSION

The combination of ciprofloxacin with a beta-actam antibiotic should be considered an important therapeutic option in hospitalized febrile neutropenic patients who have not received a quinolone for prevention of infections and in settings in which quinolone resistance is not common.

Pharmacodynamic interactions of ciprofloxacin, piperacillin, and piperacillin/tazobactam in healthy volunteers

Mathematical modeling methods were used to study pharmacokinetic and pharmacodynamic interactions of the antimicrobial combinations piperacillin plus ciprofloxacin and piperacillin plus tazobactam. Twelve healthy volunteers received the following treatments: piperacillin (4 g), ciprofloxacin (400 mg), piperacillin (4 g) plus ciprofloxacin (400 mg), and piperacillin (4 g) plus tazobactam (0.5 g), via intravenous infusion in a four-period crossover design. Serum drug concentrations were analyzed by means of high-performance liquid chromatography (HPLC), and inhibitory titers were performed against eight organisms. The pharmacodynamic response (growth or no growth) was modeled for each of the monotherapy courses using a Hill-type model where Emax was 1 (100% probability of no growth [P(NG)]), and EC50 was the concentration associated with a 50% P(NG). For piperacillin plus ciprofloxacin, P(NG) was a function of 1) plasma concentrations for both drugs; 2) EC50 values from the monotherapy courses; and 3) theta, an interaction term that accommodates synergy, additivity, or antagonism. For piperacillin/tazobactam, the serum ultrafiltrate area under the inhibitory curve was compared with that of piperacillin alone to determine the benefit of tazobactam. The interaction between piperacillin and ciprofloxacin was additive. The addition of tazobactam to piperacillin was beneficial against certain organisms. The model developed can be used to evaluate the activity of combination regimens against representative pathogens.

Ciprofloxacin. An updated review of its pharmacology, therapeutic efficacy and tolerability

Ciprofloxacin is a broad spectrum fluoroquinolone antibacterial agent. Since its introduction in the 1980s, most Gram-negative bacteria have remained highly susceptible to this agent in vitro; Gram-positive bacteria are generally susceptible or moderately susceptible. Ciprofloxacin attains therapeutic concentrations in most tissues and body fluids. The results of clinical trials with ciprofloxacin have confirmed its clinical efficacy and low potential for adverse effects. Ciprofloxacin is effective in the treatment of a wide variety of infections, particularly those caused by Gram-negative pathogens. These include complicated urinary tract infections, sexually transmitted diseases (gonorrhoea and chancroid), skin and bone infections, gastrointestinal infections caused by multiresistant organisms, lower respiratory tract infections (including those in patients with cystic fibrosis), febrile neutropenia (combined with an agent which possesses good activity against Gram-positive bacteria), intra-abdominal infections (combined with an antianaerobic agent) and malignant external otitis. Ciprofloxacin should not be considered a first-line empirical therapy for respiratory tract infections if penicillin-susceptible Streptococcus pneumoniae is the primary pathogen; however, it is an appropriate treatment option in patients with mixed infections (where S. pneumoniae may or may not be present) or in patients with predisposing factors for Gram-negative infections. Clinically important drug interactions involving ciprofloxacin are well documented and avoidable with conscientious prescribing. Recommended dosage adjustments in patients with impaired renal function vary between countries; major adjustments are not required until the estimated creatinine clearance is < 30 ml/min/1.73m2 (or when the serum creatinine level is > or = 2 mg/dl). Ciprofloxacin is one of the few broad spectrum antibacterials available in both intravenous and oral formulations. In this respect, it offers the potential for cost savings with sequential intravenous and oral therapy in appropriately selected patients and may allow early discharge from hospital in some instances. In conclusion, ciprofloxacin has retained its excellent activity against most Gram-negative bacteria, and fulfilled its potential as an important antibacterial drug in the treatment of a wide range of infections. Rational prescribing will help to ensure the continued clinical usefulness of this valuable antimicrobial drug.

Empiric therapy for infections in the febrile, neutropenic, compromised host

In the years to come, it is likely that with the advent of cytokines and even more with possibility to insert drug-resistant genes into hematopoietic stem cells, the risk of infection will be decreased because the severity and duration of neutropenia will be minimized. It is true that the ideal empiric antimicrobial regimen--a single antibiotic with a low incidence of superinfection and a low toxicity, without need for subsequent additions and readjustments--is still a wish. In the meantime and while living in the neutropenic area, physicians, for the benefit of patients, have to follow guidelines and create algorithms (see Fig. 1). Recommendations, however, should be always adjustable to the individual characteristics of the patient and the institution and to progress in antimicrobial chemotherapy. It is inevitable that research and clinical practice should go "hand in hand" in these "difficult-to-manage" and "difficult-to-treat" patients. After all, it should never be forgotten that the ultimate goal of empiric antimicrobial regimens in febrile neutropenia is to ensure patients' survival.

Pharmacodynamics of intravenous ciprofloxacin in seriously ill patients

Seventy-four acutely ill patients were treated with intravenous ciprofloxacin at dosages ranging between 200 mg every 12 h and 400 mg every 8 h. A population pharmacokinetic-pharmacodynamic analysis relating drug exposure (and other factors) to infectious outcome was performed. Plasma samples were obtained and assayed for ciprofloxacin by high-performance liquid chromatography. Samples from patients were frequently cultured so that the day of bacterial eradication could be determined. The pharmacokinetic data were fitted by iterative two-stage analysis, assuming a linear two-compartment model. Logistic regression was used to model ciprofloxacin exposure (and other potential covariates) versus the probabilities of achieving clinical and microbiologic cures. The same variables were also modelled versus the time to bacterial eradication by proportional hazards regression. The independent variables considered were dose, site of infection, infecting organism and the MIC for it, percent time above the MIC, peak, peak/MIC ratio, trough, trough/MIC ratio, 24-h area under the concentration-time curve (AUC), AUC/MIC ratio (AUIC), presence of other active antibacterial agents, and patient characteristics. The most important predictor for all three measures of ciprofloxacin pharmacodynamics was the AUIC. A 24-h AUIC of 125 SIT-1.h (inverse serum inhibitory titer integrated over time) was found to be a significant breakpoint for probabilities of both clinical and microbiologic cures. At an AUIC below 125 (19 patients), the percent probabilities of clinical and microbiologic cures were 42 and 26%, respectively. At an AUIC above 125 (45 patients), the probabilities were 80% (P < 0.005) and 82% (P < 0.001), respectively. There were two significant breakpoints in the time-to-bacterial-eradication data. At an AUIC below 125 (21 patients), the median time to eradication exceeded 32 days; at an AUIC of 125 to 250 (15 patients), time to eradication was 6.6 days: and at AUIC above 250 (28 patients), the median time to eradication was 1.9 days (groups differed; P < 0.005). These findings, when combined with pharmacokinetic data reported in the companion article, provide the rationale and tools needed for targeting the dosage of intravenous ciprofloxacin to individual patients' pharmacokinetics and their bacterial pathogens' susceptibilities. An a priori dosing algorithm (based on MIC, patient creatine clearance and weight, and the clinician-specified AUIC target) was developed. This approach was shown, retrospectively, to be more precise than current guidelines, and it can be used to achieve more rapid bacteriologic and clinical responses to ciprofloxacin, as a consequence of targeting the AUIC.