Multicenter, randomized study comparing levofloxacin and ciprofloxacin for uncomplicated skin and skin structure infections

Interventions for impetigo

BACKGROUND

Impetigo is a common, superficial bacterial skin infection, which is most frequently encountered in children. There is no generally agreed standard therapy, and guidelines for treatment differ widely. Treatment options include many different oral and topical antibiotics as well as disinfectants. This is an updated version of the original review published in 2003.

OBJECTIVES

To assess the effects of treatments for impetigo, including non-pharmacological interventions and 'waiting for natural resolution'.

SEARCH METHODS

We updated our searches of the following databases to July 2010: the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 2005), EMBASE (from 2007), and LILACS (from 1982). We also searched online trials registries for ongoing trials, and we handsearched the reference lists of new studies found in the updated search.

SELECTION CRITERIA

Randomised controlled trials of treatments for non-bullous, bullous, primary, and secondary impetigo.

DATA COLLECTION AND ANALYSIS

Two independent authors undertook all steps in data collection. We performed quality assessments and data collection in two separate stages.

MAIN RESULTS

We included 57 trials in the first version of this review. For this update 1 of those trials was excluded and 12 new trials were added. The total number of included trials was, thus, 68, with 5578 participants, reporting on 50 different treatments, including placebo. Most trials were in primary impetigo or did not specify this.For many of the items that were assessed for risk of bias, most studies did not provide enough information. Fifteen studies reported blinding of participants and outcome assessors.Topical antibiotic treatment showed better cure rates than placebo (pooled risk ratio (RR) 2. 24, 95% confidence interval (CI) 1.61 to 3.13) in 6 studies with 575 participants. In 4 studies with 440 participants, there was no clear evidence that either of the most commonly studied topical antibiotics (mupirocin and fusidic acid) was more effective than the other (RR 1.03, 95% CI 0.95 to 1.11).In 10 studies with 581 participants, topical mupirocin was shown to be slightly superior to oral erythromycin (pooled RR 1.07, 95% CI 1.01 to 1.13). There were no significant differences in cure rates from treatment with topical versus other oral antibiotics. There were, however, differences in the outcome from treatment with different oral antibiotics: penicillin was inferior to erythromycin, in 2 studies with 79 participants (pooled RR 1.29, 95% CI 1.07 to 1.56), and cloxacillin, in 2 studies with 166 participants (pooled RR 1.59, 95% CI 1.21 to 2.08).There was a lack of evidence for the benefit of using disinfectant solutions. When 2 studies with 292 participants were pooled, topical antibiotics were significantly better than disinfecting treatments (RR 1.15, 95% CI 1.01 to 1.32).The reported number of side-effects was low, and most of these were mild. Side-effects were more common for oral antibiotic treatment compared to topical treatment. Gastrointestinal effects accounted for most of the difference.Worldwide, bacteria causing impetigo show growing resistance rates for commonly used antibiotics. For a newly developed topical treatment, retapamulin, no resistance has yet been reported.

AUTHORS' CONCLUSIONS

There is good evidence that topical mupirocin and topical fusidic acid are equally, or more, effective than oral treatment. Due to the lack of studies in people with extensive impetigo, it is unclear if oral antibiotics are superior to topical antibiotics in this group. Fusidic acid and mupirocin are of similar efficacy. Penicillin was not as effective as most other antibiotics. There is a lack of evidence to support disinfection measures to manage impetigo.

Skin and skin structure infections: treatment with newer generation fluoroquinolones

Skin and skin structure infections (SSSI) are an emerging issue in healthcare. They are responsible for increasing heathcare utilization, both in hospitalizations and intravenous antibiotic use. SSSI are caused by an evolving variety of pathogens, including Gram-positive, Gram-negative, and anaerobic bacteria. In combination with mounting resistance patterns, this diverse range of bacteria mandate empiric broad-spectrum antibiotic coverage. Historically, cephalosporins and penicillins have been the mainstay of treatment, but recent data suggest newer generation fluoroquinolones are being used with increasing frequency. In 2005, moxifloxacin joined gatifloxacin and levofloxacin as newer generation fluoroquionolones with Food and Drug Administration indications for SSSIs. Even within this group there exist subtle differences that impact optimal management. This paper offers the clinician a comparative review of the antimicrobial spectrum, pharmacodynamics, pharmacokinetics, and clinical efficacy data to support the appropriate use of fluoroquinolones in SSSIs.

Fluoroquinolones vs beta-lactams for empirical treatment of immunocompetent patients with skin and soft tissue infections: a meta-analysis of randomized controlled trials

OBJECTIVE

To compare the effectiveness and safety of fluoroquinolones with beta-lactams in the treatment of patients with skin and soft tissue infections (SSTIs).

METHODS

We searched the PubMed database, Cochrane Database of Controlled Trials, and references of relevant articles for study reports published between January 1980 and February 2006.

RESULTS

Twenty randomized controlled trials that enrolled 4817 patients were included in the analysis. Fluoroquinolones as empirical treatment of patients with SSTIs were more effective than beta-lactams for the clinically evaluable patients (90.4% vs 88.2%; odds ratio [OR], 1.29; 95% confidence interval [CI], 1.00-1.66). This was also true in subset analyses of randomized controlled trials that studied ciprofloxacin (OR, 2.49; 95% CI, 1.45-4.26) and for patients with mild to moderate infections (OR, 1.83; 95% CI, 1.13-2.96). In contrast, no difference was found between the compared regimens for patients with moderate to severe infections (OR, 1.12; 95% CI, 0.80-1.55), for patients who did not receive third-generation cephalosporins as the comparator antibiotic (OR, 0.99; 95% CI, 0.73-1.34), or for the microbiologically evaluable patients (OR, 1.19; 95% CI, 0.89-1.59). Fluoroquinolones were also associated with more adverse effects (19.2% vs 15.2%; OR, 1.33; 95% CI, 1.13-1.57).

CONCLUSION

The high proportion of successfully treated patients in the compared groups of antibiotics and the development of more adverse effects associated with fluoroquinolone use suggest that these antibiotics do not have substantial advantages compared with beta-lactams for empirical treatment of patients with SSTIs.

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.

The use of fluoroquinolones in the treatment of skin infections

Fluoroquinolones have been studied for both uncomplicated and complicated skin and skin structure infections. Their broad spectrum, rapid bactericidal activity, extensive tissue penetration, excellent bioavailability and ease of administration have made these drugs a common choice for many infectious diseases, including skin infections. Extensive research has shown the fluoroquinolones to be as effective as beta-lactam antibiotics in managing a spectrum of diseases including erysipelas, cellulitis, impetigo, surgical wounds and diabetic foot infections. However, resistance to the fluoroquinolones has increased among the staphylococci, streptococci, Enterobacteriaceae and other important Gram-negative bacilli. Resistance has been linked directly to the widespread use of these compounds. Despite their appeal in the treatment of both uncomplicated and complicated skin infections, the fluoroquinolones should be reserved as alternatives to beta-lactams and other antibiotics or as empirical therapy in complicated infections until pathogens have been identified and drug regimens can be focused.

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.

Newer Treatment Options for Skin and Soft Tissue Infections

In recent years, serious skin and soft tissue infections (SSTIs) caused by multidrug resistant pathogens have become more common. While the majority of SSTIs are caused by Staphylococcus aureus or beta-haemolytic streptococci that are methicillin/oxacillin susceptible, the emergence of methicillin-resistant and vancomycin-resistant community-acquired and nosocomial Gram-positive pathogens has created a need for different therapeutic agents, such as linezolid, quinupristin/dalfopristin, daptomycin, and newer generation carbapenems and fluoroquinolones. This review focuses on agents presently in clinical development for the treatment of SSTIs caused by Gram-positive pathogens such as staphylococci, streptococci and enterococci including methicillin-resistant S. aureus (MRSA) and vancomycin-resistant enterococci (VRE). Newer-generation carbapenems, such as meropenem and ertapenem, are characterised by a broad-spectrum of activity against Gram-positive and -negative aerobes and anaerobes, and are resistant to hydrolysis by many beta-lactamases. Current-generation fluoroquinolones, such as levofloxacin, moxifloxacin and gatifloxacin, have demonstrated better eradication rates for S. aureus than conventional penicillin and cephalosporins. These antimicrobial agents can be used to treat methicillin-susceptible staphylococcal and streptococcal strains. Oxazolidinones, streptogramin combinations and cyclic lipopeptides have novel mechanisms of action and have been studied in several multinational phase III clinical trials in the treatment of complicated and uncomplicated SSTIs. They possess a broad spectrum of activity against multidrug-resistant pathogens, including MRSA and VRE. Linezolid has been shown to be active against a wide variety of community-acquired and nosocomial antimicrobial-resistant pathogens with comparability to vancomycin, as well as resulting in reduced lengths of hospital stay. Cyclic lipopeptides such as daptomycin have a unique mechanism of action by disruption of bacterial membrane electric potentials with less likelihood for development of cross-resistance. Daptomycin has recently been US FDA approved for the treatment of complicated SSTI. However, rapid development of resistance to some of these newer agents has already been reported and this trend magnifies the importance of further need for effective antimicrobial agents. Several investigational agents, such as dalbavancin, oritavancin and tigecycline, are in advanced stages of development and are likely to proceed to licensing in the next few years. With their long half-lives, these agents have an advantage of less frequent dose administration with more rapid bactericidal activity and less likelihood for development of resistance. However, because of their proven activity against highly resistant organisms, these antibacterial agents should be reserved only for life-threatening situations and/or when resistant pathogens are suspected. Rational antimicrobial use coupled with awareness of infection control measures is paramount to avert the emergence of multidrug-resistant organisms.

Interventions for impetigo

BACKGROUND

Impetigo is a common superficial bacterial skin infection, most frequently encountered in children. There is no standard therapy and guidelines for treatment differ widely. Treatment options include many different oral and topical antibiotics as well as disinfectants.

OBJECTIVES

To assess the effects of treatments for impetigo, including waiting for natural resolution.

SEARCH STRATEGY

We searched the Skin Group Specialised Trials Register (March 2002), Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1 2002), the National Research Register (2002), MEDLINE (from 1966 to January 2003), EMBASE (from 1980 to March 2000) and LILACS (November 2001). We handsearched the Yearbook of Dermatology (1938-1966), the Yearbook of Drug Therapy (1949-1966), used reference lists of articles and contacted pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials of treatments for non-bullous and bullous, primary and secondary impetigo.

DATA COLLECTION AND ANALYSIS

All steps in data collection were done by two independent reviewers. We performed quality assessments and data collection in two separate stages.

MAIN RESULTS

We included 57 trials including 3533 participants in total which studied 20 different oral and 18 different topical treatments. CURE OR IMPROVEMENT: Topical antibiotics showed better cure rates than placebo (pooled odds ratio (OR) 6.49, 95% confidence interval (CI) 3.93 to 10.73), and no topical antibiotic was superior (pooled OR of mupirocin versus fusidic acid 1.76, 95% CI 0.69 to 2.16). Topical mupirocin was superior to oral erythromycin (pooled OR 1.22, 95% CI 1.05 to 2.97). In most other comparisons, topical and oral antibiotics did not show significantly different cure rates, nor did most trials comparing oral antibiotics. Penicillin was inferior to erythromycin and cloxacillin and there is little evidence that using disinfectant solutions improves impetigo.

SIDE EFFECTS

The reported number of side effects was low. Oral antibiotic treatment caused more side effects, especially gastrointestinal ones, than topical treatment.

REVIEWERS' CONCLUSIONS

Data on the natural course of impetigo are lacking. Placebo controlled trials are scarce. There is little evidence about the value of disinfecting measures. There is good evidence that topical mupirocin and topical fusidic acid are equally, or more effective than oral treatment for people with limited disease. It is unclear if oral antibiotics are superior to topical antibiotics for people with extensive impetigo. Fusidic acid and mupirocin are of similar efficacy. Penicillin was not as effective as most other antibiotics. Resistance patterns against antibiotics change and should be taken into account in the choice of therapy.

Methicillin-resistant Staphylococcus aureus: impact on dermatology practice

Methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) emerged in the 1960s and is now commonly seen in hospitals, clinics and, since the mid-1990s, the community. Risk factors for the acquisition of MRSA include chronic dermatoses, underlying medical illnesses, attending healthcare facilities, use of prescription antibacterials, surgery, intravenous lines, hospitalization in an intensive care unit, and proximity to patients colonized with MRSA. Recent community-associated strains often occur in patients without these risk factors. Staphylococci are readily spread from person to person and readily contaminate the environment. Infection control measures thus involve identifying the infected patients, separating them from other non-infected patients, cleaning of the environment and, most important of all, scrupulous attention to hand hygiene. Alcoholic antiseptic hand rubs offer an alternative to antiseptic hand washes and increase compliance. Treatment of MRSA skin infections is challenging. Topical agents such as mupirocin or fusidic acid can be used, but the organisms often become resistant. Systemic therapy involves non-beta-lactams. Parenteral treatment is generally with glycopeptides such as vancomycin; oral therapy is more complex. Monotherapy with quinolones, rifampin (rifampicin), and fusidic acid often results in the development of resistance and so, if any of these agents are chosen it should be in combination. There are no data on combination therapy, although rifampin-containing combinations are often chosen. Fourth-generation quinolones and linezolid are expensive but promising alternatives.

A practical guide to the treatment of complicated skin and soft tissue infections

Complicated skin and soft tissue infections (SSTIs) remain a common reason for hospitalisation. Optimal management of complicated SSTIs begins with a physical examination, and obtaining the complete social and medical history of the patient. Empirical intravenous antibacterial therapy is guided by expected pathogens, patient factors and diagnostic procedure reports, such as the Gram-stained smear of discharge or exudates. The majority of community-acquired SSTIs are caused by Staphylococcus aureus and beta-haemolytic streptococci. On the basis of recent surveillance data, 80-90% of these pathogens remain susceptible to cefazolin or oxacillin. Consequently, a first generation cephalosporin or an antistaphylococcal penicillin remains the first line empirical therapy for community-acquired skin and soft tissue infections. Vancomycin may be an appropriate alternative when vancomycin-resistant S. aureus is highly suspected on the basis of patient history and co-morbid conditions. With the global emergence and spread of macrolide-resistant S. aureus and beta-haemolytic streptococci, clindamycin rather than a macrolide is the recommended agent for empirical antibacterial therapy of community-acquired SSTIs in penicillin-allergic patients. Nosocomial complicated SSTIs are predominantly caused by S. aureus, Pseudomonas aeruginosa, Enterococcus spp., Escherichia coli and other Enterobacteriaceae. Piperacillin/tazobactam with or without vancomycin is the preferred agent for empirical treatment depending on local resistance statistics. The newer fluoroquinolones may have a role in the treatment of complicated SSTIs, especially in penicillin-allergic patients. More clinical studies are needed before a formal recommendation can be made. Many of the newer antimicrobial agents such as the carbapenems, oxazolidinones and streptogramins have been shown to be effective for the treatment of complicated SSTIs. However, because of their proven activity against highly resistant organisms including methicillin-resistant S. aureus and vancomycin-resistant enterococci (oxazolidinones and streptogramins), and Gram-negative bacilli producing extended spectrum beta-lactamases (carbapenems), these antibacterials should be reserved for life-threatening situations and/or when resistant pathogens are suspected. Complicated skin and soft tissue infections are often associated with exudates, ulcerations, fluid collections or abscesses. Adequate debridement of devitalized tissues and drainage of abscesses and fluid collections in addition to systemic antibacterial therapy is an integral part of appropriate management.

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.

The Role of Fluoroquinolones in the Treatment of Skin and Soft Tissue Infection

Skin and soft tissue infections vary widely in their nature and severity, and their nomenclature is complex. Most are readily recognized and easily treated, but more severe infections may masquerade in forms similar to those of more innocent infections, causing delay in diagnosis and treatment that may result in loss of limb or life. Antimicrobial therapy is clearly beneficial for both recovery from these infections as well as preventing disease progression. The fluoroquinolones are potent broad-spectrum antimicrobial agents. The older fluoroquinolones mainly have excellent in vitro activity against gram-negative bacilli and borderline activity against clinically important gram-positive organisms, but newer fluoroquinolones were developed to have enhanced activity against both gram-positive and anaerobic organisms while retaining broad-spectrum anti-gram-negative activity. Several comparative trials using fluoroquinolones suggest that the efficacy of these agents is similar to that of b-lactam antimicrobial agents. Additional clinical trials are necessary to determine the overall role of newer fluoroquinolones as alternatives for skin and soft tissue infections.

Once-daily, high-dose levofloxacin versus ticarcillin-clavulanate alone or followed by amoxicillin-clavulanate for complicated skin and skin-structure infections: a randomized, open-label trial

This study tested whether levofloxacin, at a new high dose of 750 mg, was effective for the treatment of complicated skin and skin-structure infections (SSSIs). Patients with complicated SSSIs (n=399) were randomly assigned in a ratio of 1:1 to 2 treatment arms: levofloxacin (750 mg given once per day intravenously [iv], orally, or iv/orally) or ticarcillin-clavulanate (TC; 3.1 g given iv every 4-6 hours) followed, at the investigator's discretion, by amoxicillin-clavulanate (AC; 875 mg given orally every 12 hours). In the clinically evaluable population, therapeutic equivalence was demonstrated between the levofloxacin and TC/AC regimens (success rates of 84.1% and 80.3%, respectively). In the microbiologically evaluable population, the overall rate of eradication was 83.7% in the levofloxacin treatment group and 71.4% in the TC/AC treatment group (95% confidence interval, -24.3 to -0.2). Both levofloxacin and TC/AC were well tolerated. These data demonstrate that levofloxacin (750 mg once per day) is safe and at least as effective as TC/AC for complicated SSSIs.

Penetration of levofloxacin into skin tissue after oral administration of multiple 750 mg once-daily doses

OBJECTIVE

To probe the pharmacokinetic basis for the use of levofloxacin for complicated skin and skin-structure infections (SSSIs) at a once-daily dosage of 750 mg by investigating its penetration into skin tissue.

METHOD

Ten healthy volunteers were administered three oral, once-daily 750 mg doses of levofloxacin, and levofloxacin concentrations were subsequently measured over time (0.5-24 h) in skin-punch biopsy tissue and plasma.

RESULTS

Skin tissue concentrations consistently exceeded those in plasma at every time point, with tissue/plasma ratios of 1.37 +/- 0.81 for peak concentration and 1.97 +/- 0.35 for area under the concentration versus time curve. Three of the ten subjects reported treatment-emergent adverse events (AEs) that were considered unrelated to treatment. An 11th subject who had enrolled in the study withdrew after AEs of mild severity that were possibly related to the study drug.

CONCLUSION

The results support the clinical usage of levofloxacin 750 mg once-daily for complicated SSSIs.

Levofloxacin

Levofloxacin is the L-form of the fluoroquinolone antibacterial agent, ofloxacin. In in vitro studies, levofloxacin demonstrated a broad range of activity against Gram-positive and -negative organisms and anaerobes. The drug is more active against Gram-positive organisms than ciprofloxacin, but less active than newer fluoroquinolones such as gatifloxacin. Its activity against Streptococcus pneumoniae is unaffected by the presence of penicillin resistance. In several randomised controlled trails, 5 to 14 days' treatment with intravenous and/or oral levofloxacin proved an effective therapy for upper and lower respiratory tract infections. In patients with mild to severe community-acquired pneumonia (CAP), intravenous and/or oral levofloxacin 500mg once or twice daily was as effective as intravenous and/or oral gatifloxacin, clarithromycin, azithromycin or amoxicillin/clavulanic acid. Overall, clinical response rates with levofloxacin ranged from 86 to 95% versus 88 to 96% with comparator agents; bacteriological response rates were 88 to 95% and 86 to 98%, respectively. Sequential (intravenous +/- oral switch) therapy with levofloxacin 750mg once daily was as effective as intravenous imipenem/cilastatin (+/- oral switch to ciprofloxacin) in patients with severe nosocomial pneumonia. Generally, oral levofloxacin 250 or 500mg once daily was at least as effective as oral cefaclor, cefuroxime axetil, clarithromycin or moxifloxacin in patients with acute exacerbations of chronic bronchitis as assessed by either clinical or bacteriological response rates. This approach also provided similar efficacy to amoxicillin/ clavulanic acid or clarithromycin in patients with acute sinusitis. Sequential therapy with levofloxacin 500mg twice daily for 7 to 14 days' was as effective as intravenous imipenem/cilastatin in patients with suspected bacteraemia. Oral levofloxacin 500mg once daily for 7 to 10 days was also an effective treatment in patients with uncomplicated skin and skin structure infections, and in those with complicated urinary tract infections. A higher dosage of sequential levofloxacin 750mg once daily proved as effective as intravenous ticarcillin/clavulanic acid (+/- oral switch to amoxicillin/clavulanic acid) in the treatment of complicated skin and skin structure infections. Pharmacoeconomic studies suggest that levofloxacin may be cost-saving in comparison to conventional therapies.

CONCLUSIONS

Levofloxacin continues to demonstrate good clinical efficacy in the treatment of a range of infections, including those in which S. pneumoniae is a potential pathogen. Importantly, it has efficacy in CAP similar to that of gatifloxacin and at least as good as that of the third generation cephalosporins. Extensive clinical data confirm the good tolerability profile of this agent without the phototoxicity, hepatic and cardiac events evident with some of the other newer fluoroquinolone agents. Levofloxacin therefore offers a unique combination of documented efficacy and tolerability, and provides an important option for the treatment of bacterial infections.

Integrating fluoroquinolones into the hospital formulary

With the increasing availability of new agents, selection of fluoroquinolones for formulary inclusion can be difficult. Appropriate evaluation of the important characteristics (pharmacokinetic and pharmacodynamic properties, antimicrobial activity, efficacy, tolerability, cost) of these agents should allow selection of the most cost-effective ones. Evidence from in vitro studies and clinical trials indicates differences exist among fluoroquinolones, especially in terms of activity against gram-positive, aerobic organisms. For selected clinical situations, it may be important to choose an agent that is available in both intravenous and oral formulations. Comparative drug costs, as well as costs associated with potential clinical failure and adverse events, should be evaluated carefully. Dosage regimens should be considered, as shorter durations of therapy and less frequent dose administration may lead to reduced labor costs and increased patient compliance, thereby improving effectiveness and economic efficiency.

Is more than one quinolone needed in clinical practice?

OBJECTIVE

To review clinical information on fluoroquinolone antimicrobials to distinguish between these agents and help define their place in clinical practice.

DATA SOURCES

Primary and review articles on fluoroquinolones available commercially in the US as of August 2000 were identified through MEDLINE (from 1993-August 2000) and secondary sources.

STUDY SELECTION AND DATA EXTRACTION

All pertinent, published, clinical trials for levofloxacin, moxifloxacin, and gatifloxacin were included. Minimal data were included for quinolones with restricted or limited uses, including trovafloxacin, sparfloxacin, enoxacin, and lomefloxacin. Due to the quantity of data on ciprofloxacin, only more recent or pivotal trials or articles summarizing data on specific infections were included. Relevant information was included if it was believed to assist in differentiating between the fluoroquinolones for infections for which these agents would most commonly be considered.

DATA SYNTHESIS

Fluoroquinolones are a potent class of intravenous and oral broad-spectrum antimicrobial agents used for treating a wide range of community-acquired and nosocomial infections. More than 10 quinolones have been approved for use; although some of these have been withdrawn from the market, numerous others are under investigation. It has become increasingly important to be able to differentiate between these agents.

CONCLUSIONS

Differences in safety, antimicrobial spectrum of activity, and resistance development support the selective use of various fluoroquinolones in differing clinical situations.

Once-daily oral gatifloxacin versus oral levofloxacin in treatment of uncomplicated skin and soft tissue infections: double-blind, multicenter, randomized study

This was a double-blind, multicenter study in which 410 adults (> or =18 years of age) with uncomplicated skin and soft tissue infections (SSTIs) were randomized to receive either 400 mg of gatifloxacin orally once daily or 500 mg of levofloxacin orally once daily for 7 to 10 days. The study protocol called for four assessments-before and during treatment, at the end of treatment, and posttreatment. Efficacy evaluations included clinical response and bacterial eradication rates. Of 407 treated patients, 202 (108 women, 94 men) received gatifloxacin and 205 (111 women, 94 men) received levofloxacin. For clinically evaluable patients, the cure rates were 91% for gatifloxacin and 84% for levofloxacin (95% confidence interval [CI] for the difference, -2.0 to 15.2%). Clinical cure rates for microbiologically evaluable patients were 93% for gatifloxacin and 88% for levofloxacin (95% CI for the difference, -6.5 to 16.8%). The bacterial eradication rate was 92% for each group, with gatifloxacin eradicating 93% of the methicillin-susceptible Staphylococcus aureus isolates and levofloxacin eradicating 91% of them. Both drugs were well tolerated. Most of the adverse events were mild to moderate, and nausea was the most common adverse event in each treatment arm. Once-daily oral gatifloxacin (400 mg) is clinically efficacious and well tolerated compared with once-daily levofloxacin (500 mg) for the treatment of patients with uncomplicated SSTIs.

Safety and pharmacokinetics of multiple 750-milligram doses of intravenous levofloxacin in healthy volunteers

The safety and pharmacokinetics of a once-daily high intravenous dose of levofloxacin (750 mg) in 18 healthy volunteers were studied in a double-blind, randomized, placebo-controlled, single-center parallel group study. Levofloxacin was well tolerated, and higher maximum concentration of drug in serum and area under the concentration-time curve values were achieved. For difficult-to-treat infections, high daily doses of levofloxacin may be beneficial, and intravenous administration may be preferred in certain clinical settings, such as when treating patients in intensive care units, warranting further evaluation.

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.

The safety profile of the fluoroquinolones

BACKGROUND

Premarketing trials showed the fluoroquinolone agents to have a favorable side-effect profile, with treatment-related adverse events comprising gastrointestinal, central nervous system, and dermatologic effects that were generally mild and reversible on cessation of treatment. However, postmarketing surveillance studies have identified severe adverse events, including severe anaphylaxis, QTc-interval prolongation, and potential cardiotoxicity, associated with 3 quinolone agents that either resulted in the removal of the agent from the market (temafloxacin and grepafloxacin) or significantly restricted its use due to substantial mortality and morbidity associated with liver toxicity (trovafloxacin). To date, there have been no such significant adverse events associated with the older fluoroquinolone agents, including ciprofloxacin, ofloxacin, norfloxacin, and levofloxacin. However, there are fewer data from postmarketing surveillance studies on the most recently approved agents, such as moxifloxacin and gatifloxacin, or agents awaiting approval, such as gemifloxacin.

OBJECTIVE

This paper examines safety data from the premarketing trials and postmarketing surveillance studies of fluoroquinolones available in the United States.

METHODS

A MEDLINE search was performed to identify all English-language studies published since 1980 concerning the safety profiles of the fluoroquinolones.

CONCLUSIONS

The fluoroquinolone antibacterial agents offer broad-spectrum therapy in patients with a variety of infections. Given similar spectra of activity, the choice between quinolones may be based on differences in efficacy and safety or tolerability profiles. Most drug reactions involving these agents are minor and reversible on discontinuing treatment, but adverse effects can be associated with significant mortality and morbidity, as was seen in the case of trovafloxacin and temafloxacin.

Potential interactions of the extended-spectrum fluoroquinolones with the CNS

The new generation fluoroquinolones -- sparfloxacin, levofloxacin, grepafloxacin and trovafloxacin -- have been designed to respond to the clinical need for extended antimicrobial cover in the face of increasing global microbial resistance. Their main focus is in the treatment of respiratory infections, particularly those acquired in the community. CNS adverse effects, such as dizziness and headache, are known to occur relatively commonly with some fluoroquinolones and are not, in general, well tolerated by patients. The structural component of the fluoroquinolone molecule believed to be responsible for improved gram-positive activity is also believed to be implicated in the production of CNS adverse effects, including those arising from drug interactions with theophylline and NSAIDs. Inhibition of brain gamma-aminobutyric acid (GABA) receptor binding appears to be a strong indicator of CNS activity, though N-methyl-D-aspartate receptor binding has also been implicated. In accordance with the results of these predictive studies, clinical trials have found sparfloxacin, levofloxacin and grepafloxacin to be associated with a low incidence of CNS events. Trovafloxacin has been found to be associated with a higher incidence of CNS events (particularly lightheadedness and dizziness) than the other 3 agents. Ongoing and future clinical studies will help to define the usefulness of the predictive models, as well as reveal the full CNS adverse event profile of these and other investigational fluoroquinolones.

The new fluoroquinolones: A critical review

OBJECTIVE

This paper reviews the literature available on the new fluoroquinolones - clinafloxacin, gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin, sparfloxacin and trovafloxacin - to compare these agents with each other and contrast them with ciprofloxacin, an older fluoroquinolone.

DATA SELECTION

Published papers used were obtained by searching MEDLINE for articles published between 1994 and 1998, inclusive. References of published papers were also obtained and reviewed. Abstracts from scientific proceedings were reviewed.

DATA EXTRACTION

Due to the limited data available on several of the agents, criteria for study inclusion in the in vitro, pharmacokinetics and in vivo sections were not restrictive.

DATA SYNTHESIS

The new fluoroquinolones offer excellent Gram-negative bacillary activity and improved Gram-positive activity (eg, against Streptococcus pneumoniae and Staphylococcus aureus) over ciprofloxacin. Clinafloxacin, gatifloxacin, moxifloxacin, sparfloxacin and trovafloxacin display improved activity against anaerobes (eg, Bacteriodes fragilis). All of the new fluoroquinolones have a longer serum half-life than ciprofloxacin (allowing for once daily dosing), and several are eliminated predominantly by nonrenal means. No clinical trials are available comparing the new fluoroquinolones with each other. Clinical trials comparing the new fluoroquinolones with standard therapy have demonstrated good efficacy in a variety of infections. Their adverse effect profile is similar to that of ciprofloxacin. Clinafloxacin and sparfloxacin cause a high incidence of phototoxicity (1.5% to 14% and 2% to 11.7%, respectively), grepafloxacin causes a high incidence of taste perversion (9% to 17%) and trovafloxacin causes a high incidence of dizziness (11%). They all interact with metal ion-containing drugs (eg, antacids), and clinafloxacin and grepafloxacin interact with theophylline. The new fluoroquinolones are expensive; however, their use may result in savings in situations where, because of their potent and broad spectrum of activity, they can be used orally in place of intravenous antibiotics.

CONCLUSIONS

The new fluoroquinolones offer advantages over ciprofloxacin in terms of improved in vitro activity and pharmacokinetics. Whether these advantages translate into improved clinical outcomes is presently unknown. The new fluoroquinolones have the potential to emerge as important therapeutic agents in the treatment of respiratory tract and genitourinary tract infections.

Levofloxacin: a therapeutic review

This therapeutic review discusses the pharmacology, pharmacokinetics, in vitro activity, drug interactions, and adverse effects of levofloxacin, a fluoroquinolone antibiotic. Particular emphasis is placed on the clinical efficacy of levofloxacin and its place in therapy. Compared with ciprofloxacin and the earlier quinolone agents, levofloxacin has an improved pharmacokinetic profile that allows convenient once-daily dosing in either an oral or parenteral formulation. Levofloxacin has enhanced activity against gram-positive aerobic organisms, including penicillin-resistant pneumococci. In published comparative trials involving commonly used treatment regimens, levofloxacin had equivalent if not greater activity in the treatment of community-acquired pneumonia, acute bacterial exacerbations of chronic bronchitis, acute bacterial sinusitis, acute pyelonephritis, and complicated urinary tract infection. Levofloxacin is well tolerated and induces minimal adverse drug reactions. Based on the above attributes, it may be reasonable to include levofloxacin on the hospital formulary in place of older quinolones. More recently released quinolones such as trovafloxacin exhibit similar advantages; however, until direct comparative trials between levofloxacin and these newer agents are conducted, it is difficult to advocate one agent over another. Regardless of which quinolone is the primary agent on the formulary, it is imperative that this class of antimicrobial drugs be used with discretion to minimize the development of resistance.

Levofloxacin. Its use in infections of the respiratory tract, skin, soft tissues and urinary tract

Levofloxacin, the optically pure levorotatory isomer of ofloxacin, is a fluoroquinolone antibacterial agent. Like other fluoroquinolones, it acts on bacterial topoisomerase and has activity against a broad range of Gram-positive and Gram-negative organisms. Levofloxacin also appears to have improved activity against Streptococcus pneumoniae compared with ciprofloxacin or ofloxacin. Levofloxacin distributes well and achieves high levels in excess of plasma concentrations in many tissues (e.g., lung, skin, prostate). High oral bioavailability allows switching from intravenous to oral therapy without dosage adjustment. In patients with mild to severe community-acquired pneumonia receiving treatment for 7 to 14 days, oral levofloxacin was similar in efficacy to amoxicillin/clavulanic acid, and intravenous and/or oral levofloxacin was superior to intravenous ceftriaxone and/or oral cefuroxime axetil. With levofloxacin use, clinical success (clinical cure or improvement) rates were 87 to 96% and bacteriological eradication rates were 87 to 100%. In the 5- to 10-day treatment of acute exacerbations of chronic bronchitis, oral levofloxacin was similar in efficacy to oral cefuroxime axetil or cefaclor. Levofloxacin resulted in clinical success in 78 to 94.6% of patients and bacteriological eradication in 77 to 97%. Oral levofloxacin was also similar in efficacy to amoxicillin/clavulanic acid or oral clarithromycin in patients with acute maxillary sinusitis treated for 7 to 14 days. Equivalence between 7- to 10-day therapy with oral levofloxacin and ciprofloxacin was seen in patients with uncomplicated skin and soft tissue infections. Clinical success was seen in 97.8 and 96.1% of levofloxacin recipients and bacteriological eradication in 97.5 and 93.2%. Complicated urinary tract infections, including pyelonephritis, responded similarly well to oral levofloxacin or ciprofloxacin for 10 days or lomefloxacin for 14 days. Clinical success and bacteriological eradication rates with levofloxacin occurred in 92 to 93.3% and 93.6 to 94.7% of patients.

CONCLUSIONS

Levofloxacin can be administered in a once-daily regimen as an alternative to other fluoroquinolones in the treatment of infections of the urinary tract, skin and soft tissues. Its more interesting use is as an alternative to established treatments of respiratory tract infections. S. pneumoniae appears to be more susceptible to levofloxacin than to ciprofloxacin or ofloxacin. Other newer fluoroquinolone agents that also have enhanced in vitro antipneumococcal activity may not share the well established tolerability profile of levofloxacin, which also appears to improve on that of some older fluoroquinolones.

Double-blind evaluation of the safety and pharmacokinetics of multiple oral once-daily 750-milligram and 1-gram doses of levofloxacin in healthy volunteers

The safety and pharmacokinetics of once-daily oral levofloxacin in 16 healthy male volunteers were investigated in a randomized, double-blind, placebo-controlled study. Subjects were randomly assigned to the treatment (n = 10) or placebo group (n = 6). In study period 1, 750 mg of levofloxacin or a placebo was administered orally as a single dose on day 1, followed by a washout period on days 2 and 3; dosing resumed for days 4 to 10. Following a 3-day washout period, 1 g of levofloxacin or a placebo was administered in a similar fashion in period 2. Plasma and urine levofloxacin concentrations were measured by high-pressure liquid chromatography. Pharmacokinetic parameters were estimated by model-independent methods. Levofloxacin was rapidly absorbed after single and multiple once-daily 750-mg and 1-g doses with an apparently large volume of distribution. Peak plasma levofloxacin concentration (Cmax) values were generally attained within 2 h postdose. The mean values of Cmax and area under the concentration-time curve from 0 to 24 h (AUC0-24) following a single 750-mg dose were 7.1 microg/ml and 71.3 microg x h/ml, respectively, compared to 8.6 microg/ml and 90.7 microg x h/ml, respectively, at steady state. Following the single 1-g dose, mean Cmax and AUC0-24 values were 8.9 microg/ml and 95.4 microg x h/ml, respectively; corresponding values at steady state were 11.8 microg/ml and 118 microg x h/ml. These Cmax and AUC0-24 values indicate modest and similar degrees of accumulation upon multiple dosing at the two dose levels. Values of apparent total body clearance (CL/F), apparent volume of distribution (Vss/F), half-life (t1/2), and renal clearance (CL[R]) were similar for the two dose levels and did not vary from single to multiple dosing. Mean steady-state values for CL/F, Vss/F, t1/2, and CL(R) following 750 mg of levofloxacin were 143 ml/min, 100 liters, 8.8 h, and 116 ml/min, respectively; corresponding values for the 1-g dose were 146 ml/min, 105 liters, 8.9 h, and 105 ml/min. In general, the pharmacokinetics of levofloxacin in healthy subjects following 750-mg and 1-g single and multiple once-daily oral doses appear to be consistent with those found in previous studies of healthy volunteers given 500-mg doses. Levofloxacin was well tolerated at either high dose level. The most frequently reported drug-related adverse events were nausea and headache.