Levofloxacin versus cefuroxime axetil in the treatment of acute exacerbation of chronic bronchitis: results of a randomized, double-blind study

A Review of New Fluoroquinolones : Focus on their Use in Respiratory Tract Infections

The new respiratory fluoroquinolones (gatifloxacin, gemifloxacin, levofloxacin, moxifloxacin, and on the horizon, garenoxacin) offer many improved qualities over older agents such as ciprofloxacin. These include retaining excellent activity against Gram-negative bacilli, with improved Gram-positive activity (including Streptococcus pneumoniae and Staphylococcus aureus). In addition, gatifloxacin, moxifloxacin and garenoxacin all demonstrate increased anaerobic activity (including activity against Bacteroides fragilis). The new fluoroquinolones possess greater bioavailability and longer serum half-lives compared with ciprofloxacin. The new fluoroquinolones allow for once-daily administration, which may improve patient adherence. The high bioavailability allows for rapid step down from intravenous administration to oral therapy, minimizing unnecessary hospitalization, which may decrease costs and improve quality of life of patients. Clinical trials involving the treatment of community-acquired respiratory infections (acute exacerbations of chronic bronchitis, acute sinusitis, and community-acquired pneumonia) demonstrate high bacterial eradication rates and clinical cure rates. In the treatment of community-acquired respiratory tract infections, the various new fluoroquinolones appear to be comparable to each other, but may be more effective than macrolide or cephalosporin-based regimens. However, additional data are required before it can be emphatically stated that the new fluoroquinolones as a class are responsible for better outcomes than comparators in community-acquired respiratory infections. Gemifloxacin (except for higher rates of hypersensitivity), levofloxacin, and moxifloxacin have relatively mild adverse effects that are more or less comparable to ciprofloxacin. In our opinion, gatifloxacin should not be used, due to glucose alterations which may be serious. Although all new fluoroquinolones react with metal ion-containing drugs (antacids), other drug interactions are relatively mild compared with ciprofloxacin. The new fluoroquinolones gatifloxacin, gemifloxacin, levofloxacin, and moxifloxacin have much to offer in terms of bacterial eradication, including activity against resistant respiratory pathogens such as penicillin-resistant, macrolide-resistant, and multidrug-resistant S. pneumoniae. However, ciprofloxacin-resistant organisms, including ciprofloxacin-resistant S. pneumoniae, are becoming more prevalent, thus prudent use must be exercised when prescribing these valuable agents.

Efficacy and safety of levofloxacin in the context of other contemporary fluoroquinolones: a review

BACKGROUND

In recent years, fluoroquinolone research has focused on achieving several goals, including (1) enhanced potency against gram-positive cocci, notably Streptococcus pneumoniae, and anaerobes, while (2) maintaining potency against gram-negative pathogens, (3) optimizing pharmacokinetics and pharmacodynamics (PK/PD), and (4) minimizing potential adverse drug reactions through recognition and avoidance of structural configurations that have characterized earlier, reactive compounds.

OBJECTIVE

This review examines the efficacy and safety of fluoroquinolones and the specific clinical evidence regarding levofloxacin.

METHODS

Using published literature collected over time by the author, a review was conducted, focusing on the efficacy and safety profile of levofloxacin and other fluoroquinolones.

RESULTS

The newer fluoroquinolones have fulfilled many of the research goals described above. Levofloxacin has improved anti-gram-positive potency, PK/PD properties, a proven clinical trial record (particularly for communityacquired pneumonia [CAP]), and an excellent safety profile-in the context of the treatment of >250 million patients worldwide in the past decade. It is licensed for management of drug-resistant S pneumoniae infections in the United States and has gained widespread formulary acceptance and guideline inclusion. Studies assessing levofloxacin for CAP therapy show significant advantages over standard therapy, such as trends toward reduced IV therapy and length of hospitalization, reduced mortality, and significant associated cost reduction. In addition, levofloxacin has proved highly effective in acute exacerbations of chronic bronchitis (AECB), with excellent clinical and bacteriologic results, typical of the class, and significant advantages-in terms of clinical response, overall pathogen eradication, extension of the symptom-free period, and trends toward a reduction in the number of consultation visits and hospitalizations-over standard agents, such as the oral cephalosporins.

CONCLUSIONS

Levofloxacin offers a combination of documented efficacy and tolerability, and provides an important option for the treatment of bacterial infections, including CAP and AECB, compared with standard agents used in the management of lower respiratory tract infections.

Efficacy of levofloxacin versus cefuroxime in treating acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Antibiotic treatment is one of the major pharmacologic treatments for acute exacerbation of chronic obstructive pulmonary disease (AECOPD). However, the choice of antibiotic depends on the local resistance pattern. A multicenter, randomized, controlled trial was done in patients with AECOPD to compare the efficacy of levofloxacin with that of cefuroxime axetil.

METHODS

Patients with AECOPD and without radiographic evidence of pneumonia were enrolled and randomized to either levofloxacin 500 mg daily or cefuroxime 250 mg twice daily in the mildmoderate exacerbation group, or 500 mg twice daily in the severe exacerbation group, for seven days. Clinical efficacy and microbiologic response were evaluated 5-7 days after the last dose.

RESULTS

Treatment was clinically successful in 90.4% of patients in the levofloxacin group, and in 90.6% of patients in the cefuroxime group (95% confidence interval -9.40 to 10.91), within a noninferiority margin of 10%. The microbiologic response appeared to be higher in the levofloxacin group, but the difference was not statistically significant. The safety profile was similar in both groups.

CONCLUSION

Levofloxacin is not inferior to cefuroxime with regard to clinical efficacy in treating AECOPD.

Cefditoren versus levofloxacin in patients with exacerbations of chronic bronchitis: serum inflammatory biomarkers, clinical efficacy, and microbiological eradication

Background

The aim of this open-label, randomized, parallel-group pilot study was to evaluate the efficacy of cefditoren pivoxil and levofloxacin in terms of speed of reduction in inflammatory parameters, clinical recovery, and microbiological eradication.

Methods

Forty eligible patients with acute exacerbation of chronic bronchitis (AECB) were randomized to receive cefditoren 200 mg twice a day for 5 days (n = 20) or levofloxacin 500 mg once daily for 7 days (n = 20).

Results

The inflammatory parameters which were significantly reduced at test-of-cure with respect to visit 1 were Krebs von den Lundgen-6 (KL-6) and interleukin-6. KL-6 decreased both in the overall study population (from 19 ± 11 UI/mL to 6 ± 8 UI/mL, P = 0.000) and in the cefditoren (from 19 ± 13 UI/mL to 8 ± 10 UI/mL, P = 0.006) and levofloxacin (from 19 ± 10 UI/mL to 5 ± 5 UI/mL, P = 0.000) arms. Similarly, interleukin-6 decreased both in the overall study population (from 13.35 ± 16.41 pg/mL to 3 ± 4.7 pg/mL, P = 0.000) and in the cefditoren (from 15.90 ± 19.54 pg/mL to 4.13 ± 6.42 pg/mL, P = 0.015) and levofloxacin (from 10.80 ± 12.55 pg/mL to 1.87 ± 1.16 pg/mL, P = 0.003) arms. At the end of treatment (test-of-cure, 6–9 days after drug initiation), the clinical success rate in the overall study population was 78%; the clinical cure rate was 80% in the cefditoren arm and 75% in the levofloxacin arm. Globally, bacteriological eradication at test-of-cure was obtained in 85% of the overall study population. Both treatments were well tolerated.

Conclusion

Cefditoren represents a valid option in the treatment of mild to moderately severe cases of AECB in the outpatient care setting. Moreover, the use of this cephalosporin is associated with a significant reduction of interleukin-6 and KL-6, two key mediators of lung inflammation and epithelial damage.

Levofloxacin for the treatment of respiratory tract infections

INTRODUCTION

Fluoroquinolone use has dramatically increased since the introduction of the first respiratory fluoroquinolone in the late 1990s. Levofloxacin , like other fluoquinolones, is a potent antibiotic, due to high levels of susceptibility among Gram-negative, Gram-positive (including penicillin-resistant strains of Streptococcus pneumonia) and atypical pathogens. Levofloxacin is recommended for the treatment of community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP) and in the management of acute exacerbations of chronic bronchitis (AECB). Levofloxacin demonstrates good safety, bioavailability and tissue penetration, thus maintaining adequate concentrations at the site of infection. High-dose (750 mg), short-course (5 days) therapy regimens may offer improved treatment, especially in HAP, due to higher drug concentrations, increased adherence and the potential to reduce the development of resistance.

AREAS COVERED

This article covers medical literature published in any language since 1990 until November 2011, on 'levofloxacin', identified using PubMed and MEDLINE. The search terms used were 'levofloxacin' and 'community acquired pneumonia', 'hospital pneumonia' or 'AECB'.

EXPERT OPINION

Levofloxacin is a valuable antimicrobial agent and an optimal treatment option for AECB, CAP (as a monotherapy) and HAP (as combination therapy at a high-dose regimen). Its improved bioavailability and safety profile makes the possibility of shorter hospital stays a reality.

Pseudomonal Infections in Patients with COPD

COPD is a common disease with increasing prevalence. The chronic course of the disease is characterized by acute exacerbations that cause significant worsening of symptoms. Bacterial infections play a dominant role in approximately half of the episodes of acute exacerbations of COPD. The importance of pseudomonal infection in patients with acute exacerbations of COPD stems from its relatively high prevalence in specific subgroups of these patients, and particularly its unique therapeutic ramifications. The colonization rate of Pseudomonas aeruginosa in patients with COPD in a stable condition is low.A review of a large number of clinical series of unselected outpatients with acute exacerbations of COPD revealed that P. aeruginosa was isolated from the patients' sputum at an average rate of 4%. This rate increased significantly in COPD patients with advanced airflow obstruction, in whom the rate of sputum isolates of P. aeruginosa reached 8-13% of all episodes of acute exacerbations of COPD. However, the great majority of bacteria isolated in these patients were not P. aeruginosa, but the three classic bacteria Streptococcus pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis. The subgroup of patients, with acute exacerbations of COPD, with the highest rate of P. aeruginosa infection, which approaches 18% of the episodes, is mechanically ventilated patients. However, even in this subgroup the great majority of bacteria isolated are the above-mentioned three classic pathogens. In light of these epidemiologic data and other important considerations, and in order to achieve optimal antibacterial coverage for the common infectious etiologies, empiric antibacterial therapy should be instituted as follows. Patients with acute exacerbations of COPD with advanced airflow obstruction (FEV(1) <50% of predicted under stable conditions) should receive once daily oral therapy with one of the newer fluoroquinolones, i.e. levofloxacin, moxifloxacin, gatifloxacin, or gemifloxacin for 5-10 days. Patients with severe acute exacerbations of COPD who are receiving mechanical ventilation should receive amikacin in addition to one of the intravenous preparations of the newer fluoroquinolones or monotherapy with cefepime, a carbapenem or piperacillin/tazobactam. In both subgroups it is recommended that sputum cultures be performed before initiation of therapy so that the results can guide further therapy.

Pseudomonas aeruginosa in adults with chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Pseudomonas aeruginosa is isolated in sputum cultures from adults with chronic obstructive pulmonary disease (COPD) but the significance of the organism in this clinical setting is not well known. The purpose of this review is to critically review the literature in an effort to understand the role of P. aeruginosa in the course and pathogenesis of COPD.

RECENT FINDINGS

When examined longitudinally, two distinct patterns of carriage of P. aeruginosa are observed in adults with COPD: short-term colonization followed by clearance and long-term persistence. Acquisition of P. aeruginosa is associated with the occurrence of an exacerbation, indicating that the organism causes exacerbations. Exacerbations caused by P. aeruginosa are more likely to be seen in patients with more advanced COPD, those who have received recent antibiotic therapy and those who require mechanical ventilation for an exacerbation. A subset of adults with COPD becomes chronically colonized with P. aeruginosa, but whether such patients benefit from antimicrobial therapy is not yet known.

SUMMARY

P. aeruginosa has several different manifestations in the setting of COPD. The organism is a colonizer that is cleared quickly, causes acute exacerbations and also may cause chronic infection in a subset of adults with COPD.

New semiphysiological absorption model to assess the pharmacodynamic profile of cefuroxime axetil using nonparametric and parametric population pharmacokinetics

Cefuroxime axetil is widely used to treat respiratory tract infections. We are not aware of a population pharmacokinetic (PK) model for cefuroxime axetil. Our objectives were to develop a semiphysiological population PK model and evaluate the pharmacodynamic profile for cefuroxime axetil. Twenty-four healthy volunteers received 250 mg oral cefuroxime as a suspension after a standardized breakfast. Liquid chromatography-tandem mass spectrometry was used for drug analysis, NONMEM and S-ADAPT (results reported) were used for parametric population PK modeling, and NPAG was used for nonparametric population PK modeling. Monte Carlo simulations were used to predict the duration for which the non-protein-bound-plasma concentration was above the MIC (fT(>MIC)). A model with one disposition compartment, a saturable and time-dependent drug release from the stomach, and fast drug absorption from the intestine yielded precise (r > 0.992) and unbiased curve fits and an excellent predictive performance. The apparent clearance was 21.7 liters/h (19.8% coefficient of variation [CV]) and the volume of distribution 38.7 liters (18.3% CV). Robust (>or=90%) probabilities of target attainment (PTAs) were achieved by 250 mg cefuroxime given every 12 h (q12h) or q8h for MICs of <or=0.375 mg/liter or <or=0.5 mg/liter, respectively, for the bacteriostasis target fT(>MIC) of >or=40% and for MICs of <or=0.094 mg/liter or <or=0.375 mg/liter, respectively, for the near-maximal-killing target fT(>MIC) of >or=65%. For the >or=40% fT(>MIC) target, the PTAs for 250 mg cefuroxime q12h were >or=97.8% for Streptococcus pyogenes and penicillin-susceptible Streptococcus pneumoniae. Cefuroxime at 250 mg q12h or q8h achieved PTAs below 73% or 92%, respectively, for Haemophilus influenzae, Moraxella catarrhalis, and penicillin-intermediate S. pneumoniae for susceptibility data from various countries. Depending on the MIC distribution, 250 mg oral cefuroxime q8h instead of q12h should be considered, especially for more-severe infections that require near-maximal killing by cefuroxime.

A Review of Levofloxacin for the Treatment of Bacterial Infections

Completing its initial phases of drug development in the mid 1990s as the one of the first fluoroquinolones that could be used with confidence to treat respiratory tract infections, levofloxacin went on to become one of the most widely prescribed antibiotics in the world. Available in both oral (po) and intravenous (IV) formulations and with characteristics of over 90% bioavailability, distribution into both extracellular and intracellular pulmonary compartments, highly predictable pharmacokinetics with over 90% of the drug being excreted unchanged in urine, and reliable activity against a broad spectrum of clinically important pathogens, levofloxacin has been used successfully to treat patients with a variety of serious infectious diseases as well as common infections most often treated outside of the hospital setting. Results of clinical trials involving patients with respiratory tract, urinary tract, and skin infections have consistently shown rates of clinical success and bacteriological eradication that were comparable to other widely used broad-spectrum agents. Regimens of levofloxacin, initially involving total daily doses of 250 mg to 500 mg, but more recently regimens involving 750 mg doses, have been shown to be safe and effective. Nearly a decade and a half of clinical experience has defined a safety and tolerability profile that permits data-driven assessment of the risks and benefits of using levofloxacin. As resistance to currently available fluoroquinolones has emerged, the clinical value of levofloxacin deserves continued evaluation. However, consistently high rates of susceptibility of clinically important bacteria, especially among those bacteria that commonly cause respiratory tract infections, such as Streptococcus pneumoniae and Haemophilus influenzae, suggest that this agent will continue to be a widely used well past the 20-year anniversary of its introduction into the antibacterial armamentarium.

Pseudomonas aeruginosa in chronic obstructive pulmonary disease

RATIONALE

Pseudomonas aeruginosa is isolated from adults with chronic obstructive pulmonary disease (COPD) in cross-sectional studies. However, patterns of carriage and the role of P. aeruginosa in COPD are unknown.

OBJECTIVES

To elucidate carriage patterns, phenotypes of strains, clinical manifestations, and the antibody response to P. aeruginosa in COPD.

METHODS

A prospective study of adults with COPD was conducted. Isolates of P. aeruginosa were subjected to genotypic and phenotypic analysis. Sputum samples were studied for P. aeruginosa DNA, and immune responses were assayed.

MEASUREMENTS AND MAIN RESULTS

We analyzed longitudinal clinical data, sputum cultures, pulsed-field gel electrophoresis of bacterial DNA, polymerase chain reaction of sputum, and immunoblot assays of serum. Fifty-seven episodes of acquisition of strains of P. aeruginosa were observed in 39 of 126 patients over 10 years. Acquisition of a new strain was associated with exacerbation. Thirty-one episodes of carriage were followed by clearance of the strain; 16 were of short (<1 mo) duration. Thirteen strains demonstrated persistence, and 13 strains were of indeterminate duration. Six strains were mucoid and were more likely to persist than nonmucoid strains (P = 0.005). Antibody responses developed in 53.8% of persistent carriage and in only 9.7% of short-term carriage episodes (P = 0.003). Antibiotics did not account for clearance.

CONCLUSIONS

Two distinct patterns of carriage by P. aeruginosa were observed: (1) short-term colonization followed by clearance and (2) long-term persistence. Mucoid strains showed persistence. Acquisition of P. aeruginosa is associated with the occurrence of an exacerbation. Serum antibody responses do not mediate clearance of P. aeruginosa.

Indicators of bacterial infection in patients with acute exacerbation of chronic bronchitis for application in clinical trials of antibacterial drugs

OBJECTIVES

This study examined the accuracy of: (a) patient symptoms; (b) microscopic examination of sputum purulence (>25 WBCs and <10 epithelial cells) and (c) microscopic examination of morphological bacterial cell types, in identifying bacterial infection in patients with an acute exacerbation of chronic bronchitis (AECB) for entry to clinical trials.

METHODS

Subjects had a worsening of at least two symptoms from: dyspnoea, sputum volume, and sputum purulence (Anthonisen Type 1 or 2 exacerbation). Sputum samples were collected from all subjects.

RESULTS

A total of 97 sputum samples were evaluated. Overall, 58 (60%) subjects were culture-positive; 22 of 29 (76%) subjects with Type 2 exacerbation had a bacterial pathogen isolated compared with 36 of 68 (53%) Type 1 subjects. This difference was not statistically significant. Microscopically purulent samples were found to be significantly more likely to be culture-positive than non-purulent samples. However, the sensitivity (60%) and specificity (67%); and the positive predictive value (73%) and negative predictive value (53%) observed, means that this is not an ideal predictive test for clinical trials. A semi-quantitative approach to Gram staining was identified as a potential indicator of bacterial infection. Sputum specimens with one bacterial cell type present at >10 cells per field, or more than one cell type present with at least one type at a concentration of >25 cells per field, had a high proportion (91%) of culture-positive specimens.

CONCLUSIONS

Symptoms alone are a poor indicator of bacterial infection. A semi-quantitative examination of a Gram-stained sputum preparation was the best indicator of bacterial infection. This finding may have relevance in the design of clinical trials of antibacterial drugs in AECB.

Levofloxacin 500mg once daily versus cefuroxime 250mg twice daily in patients with acute exacerbations of chronic obstructive bronchitis: clinical efficacy and exacerbation-free interval

The long-term outcome time to relapse determined as the exacerbation-free interval (EFI) has been proposed as a standard measure for comparing the efficacy of antimicrobial therapies in acute exacerbation of chronic obstructive bronchitis (AECOB). In this 6-month, randomised, open-label study, the efficacy of 10 days of oral levofloxacin 500 mg once daily or cefuroxime 250 mg twice daily was evaluated in 689 well-defined patients experiencing AECOB episodes. In the clinically evaluable per-protocol (PPc) population and the modified intent-to-treat population, the clinical cure rates at test of cure were, respectively, 94.6% for levofloxacin versus 93.8% for cefuroxime (0.8% difference, 95% confidence interval (CI) -3.2 to 4.8) and 94.5% for levofloxacin versus 92.2% for cefuroxime (2.3% difference, 95% CI -1.8 to 6.2), whilst the probability that 25% of patients would relapse during follow-up was reached within 93 days for levofloxacin compared with 81 days for cefuroxime in the PPc population (P=0.756). A multivariate analysis revealed that only congestive heart failure and number of AECOB episodes in the previous 12 months were predictive of relapse. Safety was comparable in the two treatment groups, with possibly related treatment-emergent adverse events occurring in 5.0% and 2.9% of subjects in the levofloxacin and cefuroxime groups, respectively. In addition to demonstrating the non-inferiority of levofloxacin compared with cefuroxime in AECOB, the data from this study raise the question of whether EFI is a useful discriminative endpoint for comparing antimicrobial therapies.

The role of quinolones in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is a disease state characterized by the presence of airflow obstruction due to chronic bronchitis and/or emphysema. The airflow obstruction is generally progressive. In the past asthma was often confused with chronic obstructive pulmonary disease but as the cellular inflammatory mechanisms are quite different to chronic bronchitis and emphysema it is prudent to separate this condition of airway hyper-responsiveness. Exacerbation of chronic obstructive pulmonary disease is a considerable burden on health service resources in terms of morbidity and mortality. Approximately one half of exacerbations can be attributed to bacterial pathogens, the major pathogens being Haemophilus influenzae, Streptococcus pnemoniae and Moraxella catarrhalis. Resistance to common first-line treatment antibiotics such as the beta-lactams can be variable. Newer fluoroquinolones such as grepafloxacin, levofloxacin, sparfloxacin, clinafloxacin, moxifloxacin, gatifloxacin and gemifloxacin are characterized by improved activity against Gram positive bacteria as well as their Gram negative properties. However, more randomized controlled trials need to be accomplished before the true role of quinolones in exacerbation of chronic obstructive pulmonary disease is clearly ascertained.

[Antibiotics for acute exacerbations of chronic obstructive pulmonary disease (COPD)]

OBJECTIVE

This study had for aim to evaluate the rationale and indications for antibiotic treatment in acute exacerbations of COPD and to identify potential differences among various antibiotics available for the treatment of exacerbations in France.

METHODS

A search was performed in Medline and for references quoted in identified articles from 1995 to 2005. Open or blind randomized studies involving antibiotics available in France were reviewed.

RESULTS

About 50% of all exacerbations are related to bacterial infection. Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae are the main pathogens responsible for bacterial exacerbations. Pseudomonas aeruginosa and enterobacter spp are frequently found in patients with severe functional impairment. Increased purulence of sputum is associated with bacterial infection. Patients with severe functional impairment benefit the most from antibiotic treatment. Although new molecules have larger antibiotic spectrum and better pharmacological properties, the evidence supporting their use compared to standard therapy remains scarce.

CONCLUSIONS

Additional studies are needed to better identify the subset of patients benefiting from antibiotics and to determine whether new molecules produce significant improvement on relevant outcomes such as exacerbation free interval compared to standard therapy.

Levofloxacin in the treatment of ventilator-associated pneumonia

The use of levofloxacin in critically ill patients has progressively increased since commercial marketing of the drug in 1999, despite the fact that few studies have been designed to assess the use of levofloxacin in this population. Pharmacological characteristics, broad spectrum of activity, and tolerability account for the high interest in the drug for the treatment of different infectious diseases, including ventilator-associated pneumonia (VAP), and the recommendation of levofloxacin in guidelines developed by a number of scientific societies. According to pharmacokinetic-pharmacodynamic data, it seems reasonable to assume that an increase in activity follows from a larger dose, so that 500 mg/12 h is adequate in patients with VAP. In critically ill patients with VAP, levofloxacin monotherapy is indicated for empirical treatment of patients with early onset pneumonia without risk factors for multiresistant pathogens, and in combination therapy for late onset VAP or for patients at risk for multiresistant pathogens. The use of levofloxacin in combination therapy is supported by multiple reasons, including: increased empirical coverage in infections with suspected intracellular pathogens; substitution for more toxic antimicrobial agents (e.g., aminoglycosides) in patients with renal dysfunction and in those at risk for renal insufficiency; and severity of systemic response to infection (septic shock) that justifies multiple treatment with better tolerated antibiotics. The availability of the oral formulation allows sequential therapy, switching from the intravenous route to the oral route. Levofloxacin is well tolerated by critically ill patients, with few adverse events of mild to moderate severity.

Role of infection and antimicrobial therapy in acute exacerbations of chronic obstructive pulmonary disease

Over the past several years, the significance of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in patients with chronic airflow obstruction has become increasingly apparent due to the impact these episodes have on the natural history of disease. It is now known that frequent AECOPD can adversely affect a patient's health-related quality of life and short- and long-term pulmonary function. The economic burden of these episodes is also substantial. AECOPDs represent a local and systemic inflammatory response to both infectious and noninfectious stimuli, but the majority of episodes are likely related to bacterial or viral pathogens. Patients with purulent sputum and multiple symptoms are the most likely to benefit from treatment with antibiotics. Antibiotic choice should be tailored to the individual patient, taking into account the severity of the episode and host factors which might increase the likelihood of treatment failure. Current evidence suggests that therapeutic goals not only include resolution of the acute episode, but also prolonging the time to the next event. In the future, preventing exacerbations will likely become increasingly accepted as an additional therapeutic goal in chronic obstructive pulmonary disease patients.

Highlights on the appropriate use of fluoroquinolones in respiratory tract infections

The impact of respiratory infections on public health is increasing, and lower respiratory tract infections are a major cause of morbidity and mortality. Moreover, most antibiotic prescriptions are related to respiratory infections and this is probably one of the main determinants of the increasing rate of bacterial resistance in both community and hospital settings. This has been the catalyst for the development of new drugs, such as the new fluoroquinolones. The new fluoroquinolones have an excellent spectrum providing cover for the most important respiratory pathogens, including atypical and "typical" pathogens. The pharmacokinetic and dynamic properties of the new fluoroquinolones have a significant impact on their clinical and bacteriological efficacy. They cause a concentration-dependent killing with a sustained post-antibiotic effect. Fluoroquinolones combine exceptional efficacy with cost-effectiveness. Not surprisingly, different guidelines have inserted these agents among the drugs of choice in the empirical therapy of LRTIs. This review discusses the most recent data on the bacteriological and clinical activity of the new fluoroquinolones and critically analyses the risks of a potential overuse of this valuable new class of drugs.

Role of antimicrobial agents in the management of exacerbations of COPD

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are a common occurrence and characterize the natural history of the disease. Over the past decade, new knowledge has substantially enhanced our understanding of the pathogenesis, outcome and natural history of AECOPD. The exacerbations not only greatly reduce the quality of life of these patients, but also result in hospitalization, respiratory failure, and death. The exacerbations are the major cost drivers in consumption of healthcare resources by COPD patients. Although bacterial infections are the most common etiologic agents, the role of viruses in COPD exacerbations is being increasingly recognized. The efficacy of antimicrobial therapy in acute exacerbations has established a causative role for bacterial infections. Recent molecular typing of sputum isolates further supports the role of bacteria in AECOPD. Isolation of a new strain of Haemophilus influenzae, Moraxella catarrhalis, or Streptococcus pneumoniae was associated with a considerable risk of an exacerbation. Lower airway bacterial colonization in stable patients with COPD instigates airway inflammation, which leads to a protracted self-perpetuating vicious circle of progressive lung damage and disease progression. A significant proportion of patients treated for COPD exacerbation demonstrate incomplete recovery, and frequent exacerbations contribute to decline in lung function. The predictors of poor outcome include advanced age, significant impairment of lung function, poor performance status, comorbid conditions and history of previous frequent exacerbations requiring antibacterials or systemic corticosteroids. These high-risk patients, who are likely to harbor organisms resistant to commonly used antimicrobials, should be identified and treated with antimicrobials with a low potential for failure. An aggressive management approach in complicated exacerbations may reduce costs by reducing healthcare utilization and hospitalization.

Antimicrobial selection for community-acquired lower respiratory tract infections in the 21st century: a review of gemifloxacin

Community-acquired lower respiratory tract infections (LRTIs) are more prevalent in the elderly than in children and younger adults and form a significant proportion of all consultations and hospital admissions in this older age group. Furthermore, in a world of increasing life expectancy the trend seems unlikely to be reversed. Antimicrobial treatment of community-acquired pneumonia (CAP) must cover Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis, and in many circumstances should also cover the intracellular (atypical) pathogens. In contrast, acute exacerbations of chronic bronchitis (AECB) are mainly associated with H. influenzae and S. pneumoniae and not with atypical bacteria: in severe cases, other Gram-negative bacteria may be involved. Frequently in LRTIs, the aetiology of the infection cannot be identified from the laboratory specimens and treatment has to be empirical. In such situations it is important to not only to use an antibiotic that covers all likely organisms, but also one that has good activity against these organisms given the local resistance patterns. Gemifloxacin is a new quinolone antibiotic that targets pneumococcal DNA gyrase and topoisomerase IV and is highly active against S. pneumoniae including penicillin-, macrolide- and many ciprofloxacin-resistant strains, as well as H. influenzae and the atypical pathogens. In clinical trials in CAP and AECB, gemifloxacin has been shown to be as effective a range of comparators and demonstrated an adverse event profile that was in line with the comparator agents. In one long-term study in AECB significantly more patients receiving gemifloxacin than clarithromycin remained free of recurrence after 26 weeks. The improved potency, broad spectrum of activity and proven clinical and bacteriological efficacy and safety profile should make it a useful agent in the 21st century battle against community-acquired LRTIs.

[Efficacy of levofloxacin in the treatment of acute exacerbation of chronic bronchitis in patients with risk factors]

Studies of acute exacerbations of chronic bronchitis (EXCB) included in the approval documents of levofloxacin (LVF) were reviewed in light of the good conditions of use defined by the French marketing approval and the AFSSAPS recommendations. The approval documents included two American studies comparing LVF 500 mg/d for 5-7 days with cefaclor 750 mg/d for 7-10 days or cefuroxime axetil (CXM) 500 mg/d for 7-10 days. A new descriptive analysis of efficacy was performed on a population meeting the recommendation criteria for antibiotic treatment in patients with clinical signs of obstruction. This analysis was stratified by number of risk factors (RF) for the following aggravating conditions: age above 65 years, diabetes or corticosteroid therapy. In the American studies, clinical efficacy, measured by rate of success in the total population, in the EXCB population requiring antibiotic therapy with or without risk factors, and in the EXCB population with at least one and at least two of the above-cited risk factors was 93.4% (351/376), 93.0% (268/288), 90.4% (122/135) and 94.4% (34/36) respectively with LVF and 92.2% (354/384), 92.5% (273/295), 87.7% (128/146) and 79.3% (23/29) respectively with the compared drugs. In the European study, the clinical efficacy in the total population, in the EXCB population requiring antibiotic therapy with or without risk factors, and in the EXCB population with at least one and at least two of the above-cited risk factors was 81.9% (195/238), 82.4% (182/221), 78.9% (112/142) and 75.0% (27/36) respectively with LVF and 72.5% (166/229), 74.0% (154/208), 73.1% (95/130) and 58.3% (21/36) respectively with the compared drugs. The efficacy of levofloxacin is thus confirmed for EXCB with signs of obstruction. When stratifying for RF, the efficacy of LVG persists with increasing numbers of RF, a result not observed with the compared drugs.

Levofloxacin: a review of its use in the treatment of bacterial infections in the United States

Levofloxacin (Levaquin) is a fluoroquinolone antibacterial agent with a broad spectrum of activity against Gram-positive and Gram-negative bacteria and atypical respiratory pathogens. It is active against both penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae. The prevalence of S. pneumoniae resistance to levofloxacin is <1% overall in the US.A number of randomised comparative trials in the US have demonstrated the efficacy of levofloxacin in the treatment of infections of the respiratory tract, genitourinary tract, skin and skin structures. Sequential intravenous to oral levofloxacin 750mg once daily for 7-14 days was as effective in the treatment of nosocomial pneumonia as intravenous imipenem/cilastatin 500-1000mg every 6-8 hours followed by oral ciprofloxacin 750mg twice daily in one study. In patients with mild to severe community-acquired pneumonia (CAP), intravenous and/or oral levofloxacin 500mg once daily for 7-14 days achieved clinical and bacteriological response rates similar to those with comparator agents, including amoxicillin/clavulanic acid, clarithromycin, azithromycin, ceftriaxone and/or cefuroxime axetil and gatifloxacin. A recent study indicates that intravenous or oral levofloxacin 750mg once daily for 5 days is as effective as 500mg once daily for 10 days, in the treatment of mild to severe CAP. Exacerbations of chronic bronchitis and acute maxillary sinusitis respond well to treatment with oral levofloxacin 500mg once daily for 7 and 10-14 days, respectively. Oral levofloxacin was as effective as ofloxacin in uncomplicated urinary tract infections and ciprofloxacin or lomefloxacin in complicated urinary tract infections. In men with chronic bacterial prostatitis treated for 28 days, oral levofloxacin 500mg once daily achieved similar clinical and bacteriological response rates to oral ciprofloxacin 500mg twice daily. Uncomplicated skin infections responded well to oral levofloxacin 500mg once daily for 7-10 days, while in complicated skin infections intravenous and/or oral levofloxacin 750mg for 7-14 days was at least as effective as intravenous ticarcillin/clavulanic acid (+/- switch to oral amoxicillin/clavulanic acid) administered for the same duration. Levofloxacin is generally well tolerated, with the most frequently reported adverse events being nausea and diarrhoea; in comparison with some other quinolones it has a low photosensitising potential and clinically significant cardiac and hepatic adverse events are rare.

CONCLUSION

Levofloxacin is a broad-spectrum antibacterial agent with activity against a range of Gram-positive and Gram-negative bacteria and atypical organisms. It provides clinical and bacteriological efficacy in a range of infections, including those caused by both penicillin-susceptible and -resistant strains of S. pneumoniae. Levofloxacin is well tolerated, and is associated with few of the phototoxic, cardiac or hepatic adverse events seen with some other quinolones. It also has a pharmacokinetic profile that is compatible with once-daily administration and allows for sequential intravenous to oral therapy. The recent approvals in the US for use in the treatment of nosocomial pneumonia and chronic bacterial prostatitis, and the introduction of a short-course, high-dose regimen for use in CAP, further extend the role of levofloxacin in treating bacterial infections.

[Observational study investigating the use of levofloxacin in ICU patients]

INTRODUCTION

There is little information on the use of levofloxacin, a new quinolone, in ICU patients.

OBJECTIVE

To investigate the criteria for the use of levofloxacin (indications, forms of prescription, doses, and routes of administration) and to study tolerance in patients admitted to the ICU. Method. Prospective, observational study performed from October 2000 to November 2001 in 35 ICUs and including the first 15 patients receiving levofloxacin as monotherapy or combined treatment. Descriptive data are expressed as mean and percentage. Statistical significance was set at P < .05.

RESULTS

A total of 543 indications for treatment with levofloxacin were analyzed. The patients were 70.7% men, with a mean (SD) age of 60.2 (16.7) years, mean APACHE II score of 18.9 (7.9), and a medical underlying disease in 79.2% of cases. The ICU mortality rate was 24.1%. A total of 60% of patients required mechanical ventilation and 44.3% needed inotropic drug treatment. Levofloxacin was predominantly prescribed for treating community-acquired infections (67.8%), mainly in the respiratory tract (88.1%). An etiological diagnosis was established in only 55.6% of cases. The most common pathogens were Streptococcus pneumoniae (12.7%), Haemophilus influenzae (9.1%), Escherichia coli (7.4%), methicillin-sensitive Staphylococcus aureus (7.2%), Pseudomonas aeruginosa (4.9%), and Legionella pneumophila (4.7%). In 87.1% of indications, levofloxacin was prescribed as empirical treatment. Susceptibility of the isolated pathogens to this antibiotic was confirmed in 32.2% of cases. The initial dose was 500 mg/24 h in 48.5% of indications and 500 mg/12 h in 48.3%. Combined treatment was given in 49.7% of cases. In 32.2% of cases, parenteral administration of levofloxacin was changed to oral route. Adverse events probably or possibly associated with levofloxacin occurred in only 12.5% of patients and mainly included increased ALT/ALS levels (4.4%), diarrhea (2.3%), and heart rhythm alterations (2.1%).

CONCLUSIONS

This study describes the profile of critically ill patients receiving levofloxacin and the different forms of its use in the ICU.

Acute bronchitis: state of the art diagnosis and therapy

In managing acute bronchitis, pneumonia or an exacerbation of underlying chronic bronchitis should be excluded. Simple bronchitis is best treated symptomatically while an exacerbation of chronic bronchitis can be treated with antibiotics. Broad spectrum antibiotics are appropriate in selected patients.

Current and future perspectives for levofloxacin in severe Pseudomonas aeruginosa infections

The question of whether levofloxacin includes Pseudomonas aeruginosa in its spectrum of clinical activity is discussed by reviewing the major findings on this issue, mainly those published in Italy. The in vitro activity of levofloxacin against P. aeruginosa is now documented on thousands of strains worldwide. The pharmacodynamic properties of levofloxacin allow for the treatment of pseudomonal infections. The levofloxacin clinical results extrapolated from published studies document the efficacy of levofloxacin in the treatment of infections sustained by P. aeruginosa.

Therapeutic potential of the new quinolones in the treatment of lower respiratory tract infections

The impact of respiratory infections on public health is increasing and lower respiratory tract infections are a major cause of morbidity and mortality. We are also facing a worldwide burst of antibiotic bacterial resistance. The new fluoroquinolones have an excellent spectrum covering the most important respiratory pathogens, including atypical and 'typical' pathogens. Pharmacokinetic and dynamic properties of the new fluoroquinolones have a significant impact on their clinical and bacteriological efficacy. They cause a concentration-dependent killing with a sustained postantibiotic effect. Fluoroquinolones combine exceptional efficacy with cost-effectiveness. Not surprisingly, different guidelines have inserted these agents among the drugs of choice in the empirical therapy of community-acquired pneumonia. This review discusses the more recent data on bacteriological and clinical activity and critically analyses the risks of a potential overuse of this valuable new class of drugs.

Randomised double-blind comparison of oral gatifloxacin and co-amoxiclav for acute exacerbation of chronic Bronchitis

Antimicrobial therapy can have a significant impact in the treatment of acute infectious exacerbations in patients with chronic bronchitis, in whom repeated episodes are common. The aim of this randomised, double-blind, double-dummy, parallel group study was to compare the efficacy and safety of oral gatifloxacin (200 and 400 mg once daily) administered for 5 days with co-amoxiclav (500 mg amoxicillin/125 mg clavulanic acid t.i.d.) administered for 10 days in 414 adult patients with acute exacerbation of chronic bronchitis. Overall clinical response rates (cure plus improvement) were 86.2%, 79.4% and 81.7% in the gatifloxacin 200 mg, gatifloxacin 400 mg and co-amoxiclav groups, respectively, and the equivalence hypothesis used for statistical analysis showed equivalent efficacy for both gatifloxacin 200 and 400 mg compared to co-amoxiclav. The same was true for rates of bacterial response, with eradication or presumed eradication of causative pathogens achieved in 87.5%, 87.3% and 79.1% of cases in the gatifloxacin 200 mg, gatifloxacin 400 mg and co-amoxiclav groups, respectively. All treatments were well tolerated, with the nature and frequency of treatment-related adverse events similar in all groups. The results of the study show that gatifloxacin is a safe and effective agent for the treatment of patients with chronic bronchitis experiencing an acute infectious exacerbation.

Telithromycin is as effective as amoxicillin/clavulanate in acute exacerbations of chronic bronchitis

This randomized, double-blind study evaluated the efficacy and safety of a short, 5-day course of telithromycin, a new ketolide antibacterial, compared with a standard 10-day course of amoxicillin/clavulanate, in the treatment of acute exacerbations of chronic bronchitis (AECB). The study enrolled 325 adult patients with AECB and a history of chronic obstructive pulmonary disease (COPD). Patients received either telithromycin 800 mg once daily (qd) for 5 days (followed by placebo for 5 days) or amoxicillin/clavulanate 500/125 mg three times daily (tid) for 10 days. Clinical cure rates for telithromycin post-therapy (Days 17-21, test-of-cure) and late post-therapy (Days 31-36) were 86.1 and 78.1%, respectively; 82.1 and 75.0% for amoxicillin/clavulanate. Excellent clinical cure rates were also observed for high-risk patients. Bacteriologic outcome was satisfactory for 69.2% of telithromycin recipients vs 70.0% for amoxicillin/clavulanate recipients. Both treatments were generally well tolerated, although the frequency of drug-related adverse events was almost two-fold higher for amoxicillin/clavulanate (25.0 vs. 13.1%). Thus, a 5-day course of telithromycin 800 mg qd is an effective and well-tolerated alternative to a standard 10-day course of amoxicillin/clavulanate 500/125 mg tid for first-line empiric treatment of AECB in adults with COPD.

Outcome of treatment of respiratory tract infections due to Streptococcus pneumoniae, including drug-resistant strains, with pharmacokinetically enhanced amoxycillin/clavulanate

The efficacy of a new pharmacokinetically enhanced formulation of amoxycillin/clavulanate (AMX/CA) 2000/125 mg, twice daily, designed to provide adequate levels of amoxycillin over the 12-h dosing interval to eradicate penicillin-resistant Streptococcus pneumoniae (PRSP) with amoxycillin (+/-clavulanic acid) MICs of </=4 mg/l, was evaluated in patients with respiratory infections caused by S. pneumoniae, including PRSP (penicillin MICs 2-16 mg/l). Data from nine clinical studies were combined (total intent-to-treat N=5531). Six randomized, double-blind studies used levofloxacin 500 mg od in acute bacterial sinusitis (ABS), levofloxacin 500 mg od in acute exacerbations of chronic bronchitis (AECB), clarithromycin 500 mg bid in AECB, AMX/CA 875/125 mg bid and tid in community-acquired pneumonia (CAP) and AMX/CA 1000/125 mg tid in CAP as comparators. The three remaining studies (two in ABS and one in CAP) were non-comparative. In the AMX/CA 2000/125 mg bid-treated patients evaluable at follow-up (Day 14-39), outcome was successful in 60/64 (93.7%) patients with S. pneumoniae infections in the comparative studies and 348/363 (95.9%) in the non-comparative studies, including 95.6% of all patients and 95.2% of patients whose isolates had AMX/CA MICs of >/=4 mg/l. In the pooled comparator group, the success rate at follow-up was 86.5% (45/52). For PRSP (AMX/CA MICs of 0.5-8 mg/l), the overall success rate was 98.2% (55/56) at follow-up for AMX/CA 2000/125 mg and 50.0% (2/4) for comparators. AMX/CA 2000/125 mg shows efficacy comparable to that of the comparators evaluated against S. pneumoniae infections. Due to its favorable pharmacokinetic/pharmacodynamic profile and promising clinical success, the new AMX/CA 2000/125 mg formulation should be considered for the empirical treatment of respiratory tract infections in regions with a high prevalence of antimicrobial-resistant S. pneumoniae and in patients at high risk of antimicrobial-resistant S. pneumoniae infection as this formulation covers many PRSP that are non-susceptible to amoxycillin (+/-clavulanic acid) (MICs of >/=4 mg/l) as well as common beta-lactamase-producing respiratory pathogens.

Evaluation and cost assessment of fluoroquinolones in community-acquired respiratory infections

Several new fluoroquinolones have been marketed since the late 1990s. Fluoroquinolones are an effective treatment for most community-acquired respiratory tract infections, including acute sinusitis, acute exacerbations of chronic bronchitis and community-acquired pneumonia. However, other antibiotics, including beta-lactams, macrolides, tetracyclines and trimethoprim-sulfamethoxazole, are also effective against these respiratory infections. From a managed care perspective, it is the subtle differences between the drugs in the eradication of bacterial pathogens, adverse effects, dose regimens, compliance issues, bacterial resistance and cost that determine the best choice for the management of pneumonia, sinusitis or exacerbations of chronic bronchitis. The potential for bacterial resistance is perhaps the only significant barrier to extensive fluoroquinolone use in community-acquired respiratory tract infections. Cost-effectiveness must be balanced with quality care, both from an individual perspective and that of the greater society.

Oral fluoroquinolones in the treatment of pneumonia, bronchitis and sinusitis

BACKGROUND

Despite a relatively large number of clinical studies comparing oral fluoroquinolones to one antibiotic class comparator, there is limited information on the relative efficacy of different fluoroquinolones.

OBJECTIVE

To examine the efficacy and tolerability of oral fluoroquinolones in the treatment of mild to moderate community-acquired pneumonia, acute exacerbations of chronic bronchitis and sinusitis.

METHODS

A systematic review was undertaken with a MEDLINE search for antibiotics and indications. Included studies met the following criteria: original study; random allocation to treatment groups; treatment with one of the following oral antibiotics - moxifloxacin, levofloxacin, ciprofloxacin, gatifloxacin; controlled by either placebo or an active comparator medication; double-blind, single-blind or open treatment; men and women (18 years of age and older); diagnosis of one of the three indications; and treatment duration of at least three days. Outcome measures included efficacy and safety. Comparative and single arm meta-analyses were conducted. Statistical differences in antibiotic success rates were evaluated. Pooled point estimates and 95% CIs for the comparative statistics (z-scores, P-values) and the single-arm analysis were examined to evaluate equivalence.

RESULTS

The results of the comparative and single meta-analyses revealed no major differences between the new fluoroquinolones. This is not surprising because the clinical studies were designed to show equivalence versus their comparators. Few comparative evaluations were conducted due to a paucity of studies. In relation to other competitors, small differences were seen.

CONCLUSIONS

Results indicate that, in general, fluoroquinolones had similar efficacy, overall safety and dropout rates.

Antibiotics in the treatment of acute exacerbations of chronic bronchitis

The benefit of antimicrobial therapy for patients with an acute exacerbation of chronic bronchitis (AECB) remains controversial for two main reasons. First, the distal airways of patients with chronic bronchitis are persistently colonised, even during clinically stable periods, with the same bacteria that have been associated with AECB. Second, bacterial infection is only one of several causes of AECB. These factors have led to conflicting analyses on the role of bacterial agents and the response to antimicrobial therapy of patients with AECB. An episode of AECB is said to be present when a patient with chronic obstructive pulmonary disease (COPD) experiences some combination of increased dyspnoea, increased sputum volume, increased sputum purulence and worsening lung function. While the average COPD patient experiences 2 - 4 episodes of AECB per year, some patients, particularly those with more severe airway obstruction, are more susceptible to these attacks than others. Bacterial agents appear to be particularly associated with AECB in patients with low lung function and those with frequent episodes accompanied by purulent sputum. Non-typeable Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis account for up to 50% of episodes of AECB. Gram-negative bacilli are more likely to occur in patients with more severe lung disease. Antibiotics have been used to ameliorate AECB, to prevent AECB and to prevent the long-term loss of lung function that characterises COPD. Numerous prevention trials have been conducted with fairly consistent results; antibiotics do not lessen the number of episodes of AECB but do reduce the number of days lost from work. Most antibiotic trials have studied the impact of treatment on episodes of AECB and results have been inconsistent, largely due to patient selection and end point definition. In patients with severe airway obstruction, especially in the presence of purulent sputum, antibiotic therapy significantly shortens the duration of symptoms and can be cost-effective. Over the past 50 years, virtually all classes of antimicrobial agents have been studied in AECB. Important considerations include penetration into respiratory secretions, spectrum of activity and antimicrobial resistance. These factors limit the usefulness of drugs such as amoxicillin, erythromycin and trimethoprim-sulfamethoxazole. Extended-spectrum oral cephalosporins, newer macrolides and doxycycline have demonstrated efficacy in clinical trials. Amoxicillin-clavulanate and flouoroquinolones should generally be reserved for patients with more severe disease. A number of investigational agents, including ketolides and newer quinolones, hold promise for treatment of AECB.

A critical review of the fluoroquinolones: focus on respiratory infections

The new fluoroquinolones (clinafloxacin, gatifloxacin, gemifloxacin, grepafloxacin, levofloxacin, moxifloxacin, sitafloxacin, sparfloxacin and trovafloxacin) offer excellent activity against Gram-negative bacilli and improved Gram-positive activity (e.g. against Streptococcus pneumoniae and Staphylococcus aureus) over ciprofloxacin. Ciprofloxacin still maintains the best in vitro activity against Pseudomonas aeruginosa. Clinafloxacin, gatifloxacin, moxifloxacin, sitafloxacin, sparfloxacin and trovafloxacin display improved activity against anaerobes (e.g. Bacteroides fragilis) versus ciprofloxacin. All of the new fluoroquinolones display excellent bioavailability and have longer serum half-lives than ciprofloxacin allowing for once daily dose administration. Clinical trials comparing the new fluoroquinolones to each other or to standard therapy have demonstrated good efficacy in a variety of community-acquired respiratory infections (e.g. pneumonia, acute exacerbations of chronic bronchitis and acute sinusitis). Limited data suggest that the new fluoroquinolones as a class may lead to better outcomes in community-acquired pneumonia and acute exacerbations of chronic bronchitis versus comparators. Several of these agents have either been withdrawn from the market, had their use severely restricted because of adverse effects (clinafloxacin because of phototoxicity and hypoglycaemia; grepafloxacin because of prolongation of the QTc and resultant torsades de pointes; sparfloxacin because of phototoxicity; and trovafloxacin because of hepatotoxicity), or were discontinued during developmental phases. The remaining fluoroquinolones such as gatifloxacin, gemifloxacin, levofloxacin and moxifloxacin have adverse effect profiles similar to ciprofloxacin. Extensive post-marketing safety surveillance data (as are available with ciprofloxacin and levofloxacin) are required for all new fluoroquinolones before safety can be definitively established. Drug interactions are limited; however, all fluoroquinolones interact with metal ion containing drugs (eg. antacids). The new fluoroquinolones (gatifloxacin, gemifloxacin, levofloxacin and moxifloxacin) offer several advantages over ciprofloxacin and are emerging as important therapeutic agents in the treatment of community-acquired respiratory infections. Their broad spectrum of activity which includes respiratory pathogens such as penicillin and macrolide resistant S. pneumoniae, favourable pharmacokinetic parameters, good bacteriological and clinical efficacy will lead to growing use of these agents in the treatment of community-acquired pneumonia, acute exacerbations of chronic bronchitis and acute sinusitis. These agents may result in cost savings especially in situations where, because of their potent broad-spectrum activity and excellent bioavailability, they may be used orally in place of intravenous antibacterials. Prudent use of the new fluoroquinolones will be required to minimise the development of resistance to these agents.

Selection of clinical, patient-reported, and economic end points in acute exacerbation of chronic bronchitis

BACKGROUND

Acute exacerbation of chronic bronchitis (AECB) places tremendous burden on patients, providers, employers, and health care systems.

OBJECTIVE

The purpose of this paper is to (1) review the clinical, patient-reported, and economic measures used to evaluate disease burden and treatment effectiveness in AECB in clinical trials and (2) propose a guide for selecting study end points in AECB that will help capture all the relevant disease outcomes.

METHODS

Two literature searches of the PubMed database were conducted to identify studies of clinical trials in bronchitis and evaluate the clinical, patient-reported, and economic end points used in these studies.

RESULTS

Previous studies have focused primarily on clinician-assessed outcomes, which do not capture the full impact of AECB on patients' lives. Reporting mechanisms for most end points have been inconsistent, limiting the ability to compare information or interpret differences. Previous studies have given limited attention to patient-reported outcomes and the economic implications of AECB. Patient-reported outcomes such as speed of symptom relief and work productivity are important parameters for assessing treatment effectiveness and provide practical information for treatment evaluation.

CONCLUSIONS

Additional research is needed to develop, examine, and validate patient-reported outcomes and the indirect costs of AECB. Measuring the relevant clinical, economic, and patient-reported outcomes in AECB patients using standardized methods may lead to a clearer understanding of the disease burden and the role, effectiveness, and cost-effectiveness of antibiotic treatment.

Acute exacerbations of chronic bronchitis: what role for the new fluoroquinolones?

Acute exacerbations of chronic bronchitis (AECB) are a major cause of morbidity and mortality. Bacterial pathogens are implicated in about half the episodes of AECB. Empirical antibacterials have a significant benefit in AECB; however, several recent developments have considerably complicated antibacterial choice for this condition. New fluoroquinolone antibacterials introduced in the last decade are theoretically well suited for the treatment of AECB, as the in vitro antimicrobial spectrum of these drugs includes all the major pathogens involved. The pharmacokinetic and pharmacodynamic properties of the new fluoroquinolones are superior to many other antibacterials used to treat AECB. In trials, clinical success with the new fluoroquinolones was equivalent and bacteriological success was occasionally superior to nonfluoroquinolone comparators. However, these clinical trials did not assess several potentially important end-points for which the theoretical superiority of the fluoroquinolones may translate into differences in outcome. Rare but serious adverse effects with some of the new fluoroquinolones have shaken the confidence of prescribing physicians in this class of drugs. Emergence of the resistance of Streptococcus pneumoniae to fluoroquinolones has raised concerns about indiscriminate and widespread use of the new agents for trivial infections. Patients with AECB are a heterogeneous population who should be stratified in order to appropriately choose empirical antibacterial therapy. Highly efficacious antibacterial therapy, such as the new fluoroquinolones, is appropriate as a first-line choice for patients who have risk factors for a poor outcome or are in intensive care units. Such selected use of the new fluoroquinolones balances individual benefit with societal concerns of the use of these agents for AECB.

Bacterial infection in chronic obstructive pulmonary disease in 2000: a state-of-the-art review

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States. The precise role of bacterial infection in the course and pathogenesis of COPD has been a source of controversy for decades. Chronic bacterial colonization of the lower airways contributes to airway inflammation; more research is needed to test the hypothesis that this bacterial colonization accelerates the progressive decline in lung function seen in COPD (the vicious circle hypothesis). The course of COPD is characterized by intermittent exacerbations of the disease. Studies of samples obtained by bronchoscopy with the protected specimen brush, analysis of the human immune response with appropriate immunoassays, and antibiotic trials reveal that approximately half of exacerbations are caused by bacteria. Nontypeable Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae are the most common causes of exacerbations, while Chlamydia pneumoniae causes a small proportion. The role of Haemophilus parainfluenzae and gram-negative bacilli remains to be established. Recent progress in studies of the molecular mechanisms of pathogenesis of infection in the human respiratory tract and in vaccine development guided by such studies promises to lead to novel ways to treat and prevent bacterial infections in COPD.

Steady-state plasma and intrapulmonary concentrations of levofloxacin and ciprofloxacin in healthy adult subjects

STUDY OBJECTIVE

To determine the steady-state plasma, epithelial lining fluid (ELF), and alveolar macrophage (AM) concentrations of levofloxacin and ciprofloxacin.

DESIGN

Multiple-dose, open-label, randomized pharmacokinetic study.

PARTICIPANTS

Thirty-six healthy, nonsmoking adult subjects were randomized either to oral levofloxacin, 500 or 750 mg once daily for five doses, or ciprofloxacin, 500 mg q12h for nine doses.

INTERVENTIONS

Venipuncture, bronchoscopy, and BAL were performed in each subject at 4 h, 12 h, or 24 h after the last administered dose of antibiotic.

MEASUREMENT AND RESULTS

Mean plasma concentrations of levofloxacin and ciprofloxacin were similar to those previously reported. For once-daily dosing of levofloxacin, 500 mg, the mean (+/- SD) steady-state concentrations at 4 h, 12 h, and 24 h in ELF were 9.9 +/- 2.7 microg/mL, 6.5 +/- 2.5 microg/mL, and 0.7 +/- 0.4 microg/mL, respectively; AM concentrations were 97.9 +/- 80.0 microg/mL, 36.7 +/- 23.4 microg/mL, and 13.8 +/- 16.0 microg/mL, respectively. For levofloxacin, 750 mg, the mean steady-state concentrations in ELF were 22.1 +/- 14.9 microg/mL, 9.2 +/- 5.3 microg/mL, and 1.5 +/- 0.8 microg/mL, respectively; AM concentrations were 105.1 +/- 65.5 microg/mL, 36.2 +/- 26.1 microg/mL, and 15.1 +/- 2.0 microg/mL, respectively. The concentrations of ciprofloxacin at 4 h and 12 h in ELF were 1.9 +/- 0.9 microg/mL and 0.4 +/- 0.1 microg/mL, respectively; AM concentrations were 34.9 +/- 23.2 microg/mL and 6.8 +/- 5.9 microg/mL, respectively. The differences in the ELF concentrations of the two levofloxacin groups vs those of the ciprofloxacin group were significant (p < 0.05) at each sampling time.

CONCLUSIONS

Levofloxacin was more extensively distributed into intrapulmonary compartments than ciprofloxacin and achieved significantly higher steady-state concentrations in plasma and ELF during the 24 h after drug administration.

The spectrum of acute bronchitis. Using baseline factors to guide empirical therapy

The optimal therapy for acute bronchitis depends on the causative pathogen and the presence or absence of underlying lung disease. Because there is no fast, reliable way to identify the pathogen, physicians have to rely on clinical judgment and epidemiologic characteristics. In this article, Drs Flaherty, Saint, Fendrick, and Martinez discuss how an evidence-based approach to treatment may help ensure that efficacious therapy is available in the future.

[Use of levofloxacine in primary care for outbreaks in COPD]

OBJECTIVE

To find scientific evidence to support the indication for treating outbreaks in COPD patients on an out-patient basis with levofloxacine, as against conventional treatments.

DESIGN

Standardised review, following the criteria of medicine based on the evidence. A bibliographic search of the MEDLINE data base from 1966 to June 2000 was the basis for an analysis of the evidence found.

SETTING

Non-hospital treatment.

PATIENTS AND OTHER PARTICIPANTS

COPD patients suffering a light outbreak of probable bacterial origin, according to the Anthonisen criteria.

INTERVENTIONS

The intervention analysed was treatment with 500 mg/day of levofloxacine taken orally. An attempt was made to compare this with conventional treatments such as amoxycillin-clavulanic acid and acetyl cefuroxime. The indicators of results analysed were reduction in mortality or in the number of hospital admissions.

MEASUREMENTS AND MAIN RESULTS

No clinical trial was found that compared levofloxacine and amoxycillin-clavulanic acid. Two clinical trials were found that compared levofloxacine and acetyl cefuroxime. These found no significant differences between the group treated with levofloxacine and the group treated with cefuroxime.

CONCLUSIONS

No scientific evidence demonstrating advantages of levofloxacine treatment over amoxycillin-clavulanic acid was found, or over acetyl cefuroxime as empirical PC first-choice treatment for patients with outbreaks of COPD.

A Risk-Benefit Assessment of Levofloxacin in Respiratory, Skin and Skin Structure, and Urinary Tract Infections

As a class, the quinolone antibacterials can no longer be assumed to be both effective and relatively free of significant adverse effects. Recent safety issues with newer generation fluoroquinolones, and concerns regarding drug-use associated bacterial resistance have made all drugs in this class subject to intense scrutiny and further study. Levofloxacin is a second generation fluoroquinolone with a post marketing history of well tolerated and successful use in a variety of clinical situations. Quinolones as a class cause a variety of adverse effects, including phototoxicity, seizures and other CNS disturbances, tendonitis and arthropathies, gastrointestinal effects, nephrotoxicity, prolonged QTc interval and torsade de pointes, hypo- or hyperglycaemia, and hypersensitivity reactions. Levofloxacin has been involved in only a few case reports of adverse events, which include QTc prolongation, seizures, glucose disturbances, and tendonitis. Levofloxacin has been shown to be effective at dosages of 250mg to 500mg once-daily in clinical trials in the management of acute maxillary sinusitis, acute bacterial exacerbations of chronic bronchitis, community-acquired pneumonia, skin and skin structure infections, and urinary tract infections. There are data suggesting that levofloxacin may promote fluoroquinolone resistance among the Streptococcus pneumoniae, and that clinical failures may result from this therapy. Other data suggest that fluoroquinolones with lower potency against Pseudomonas aeruginosa than ciprofloxacin, such as levofloxacin, may drive class-wide resistance to this pathogen. Levofloxacin is an effective drug in many clinical situations, but its cost is significantly higher than amoxicillin, erythromycin, or first and second generation cefalosporins. Because of the propensity to select for fluoroquinolone resistance in the pneumococcus and potentially other pathogens, levofloxacin should be an alternative agent rather than a drug-of-choice in routine community-acquired respiratory tract, urinary tract, and skin or skin structure infections. In areas with increasing pneumococcal beta-lactam resistance, levofloxacin may be a reasonable empiric therapy in community-acquired respiratory tract infections. Similarly, in patients with risk factors for infectious complications or poor outcome, levofloxacin may be an excellent empiric choice in severe community-acquired respiratory tract infections, urinary tract infections, complicated skin or skin structure infections, and nosocomial respiratory and urinary tract infections. Better clinical data are needed to identify the true place in therapy of the newer fluoroquinolones in common community-acquired and nosocomial infections. Until then, these agents, including levofloxacin, might best be reserved for complicated infections, infection recurrence, and infections caused by beta-lactam or macrolide-resistant pathogens.

Comparative in vitro activity and pharmacodynamics of five fluoroquinolones against clinical isolates of Streptococcus pneumoniae

STUDY OBJECTIVE

To compare in vitro activity and pharmacodynamics of five fluoroquinolones against clinical isolates of Streptococcus pneumoniae.

DESIGN

In vitro analysis.

SETTING

University research laboratory.

INTERVENTION

Minimum inhibitory concentrations (MICs) were determined for penicillin and five fluoroquinolones by E test for 201 S. pneumoniae isolates. Serum concentration-time profiles were simulated for the following regimens: ciprofloxacin 750 mg orally every 12 hours and 400 mg intravenously every 8 hours; levofloxacin 500 mg orally and intravenously every 24 hours; trovafloxacin 200 mg orally and intravenously every 24 hours; gatifloxacin 400 mg orally and intravenously every 24 hours; and clinafloxacin 200 mg orally and intravenously every 12 hours.

MEASUREMENTS AND MAIN RESULTS

Free 24-hour areas under the serum concentration-time curves (AUC0-24) were calculated using the trapezoidal rule, and the average AUC0-24:MIC ratio was calculated for each regimen. Differences in ratios among agents were determined by analysis of variance (Scheffe post hoc test, p < 0.05). For intravenous dosing, the average AUC0-24:MIC for gatifloxacin, clinafloxacin, trovafloxacin, ciprofloxacin, and levofloxacin was 146, 142, 122, 71, and 61, respectively. For both oral and intravenous regimens, gatifloxacin and clinafloxacin ratios were significantly greater than those for trovafloxacin, levofloxacin, and ciprofloxacin (p < or = 0.007). Ratios for trovafloxacin were significantly greater than those for levofloxacin and ciprofloxacin (p < 0.0001), and levofloxacin and ciprofloxacin ratios were not significantly different from each other.

CONCLUSION

Gatifloxacin and clinafloxacin achieve significantly higher AUC0-24:MIC ratios for S. pneumoniae than trovafloxacin, levofloxacin, and ciprofloxacin. Large comparative studies are necessary to determine the clinical significance of these findings.