A risk-benefit assessment of levofloxacin in respiratory, skin and skin structure, and urinary tract infections

Antibiotics in fish caught from ice-sealed waters: Spatial and species variations, tissue distribution, bioaccumulation, and human health risk

Antibiotics are increasingly detected in fish caught in ice-free waters, but information on fish caught in ice-sealed waters is insufficient. The concentrations of 23 antibiotics in the gills, muscles, kidneys, livers, biles, and brains of Cyprinus carpio and Hypophthalmichthys nobilis caught during winter fish-hunting activities in Chagan Lake, Haernao Reservoir, and Shitoukoumen Reservoir were systematically studied to ascertain the variations among fish species and fishing regions, tissue distribution, and bioaccumulation, as well as the potential risk to humans via the consumption of contaminated fish. The results indicated that the individual antibiotic concentration in tissues ranged from undetectable to 35.0 ng/g ww. The total antibiotic concentration in fish muscles from Shitoukoumen Reservoir was lower than that from Chagan Lake and Haernao Reservoir, but showed no significant difference between Cyprinus carpio and Hypophthalmichthys nobilis. Chloramphenicols had a high proportion in most fish tissues ranging from 28.3% to 44.0%, and the antibiotics were mainly distributed in the livers with a total concentration of 54.8 ± 9.9 ng/g ww. The mean values of bioaccumulation factors (BAF) of antibiotics in tissues ranged from 79.4 to 1000 L/kg, with the higher values found in the fish livers. The hazard quotient and hazard index value of antibiotics in the muscles of fish from ice-sealed were less than 1, indicating a negligible risk to human health via the consumption of fish muscles. This study revealed that the total antibiotic concentration in muscles showed spatial variations but not fish species-dependence. The antibiotics mainly accumulated in the livers. In addition, the target antibiotic concentrations in the muscles of fish from ice-sealed waters met the safe for consumption criteria.

Approaches for setting occupational exposure limits in the pharmaceutical industry

The use of pharmaceutical drugs has provided a cure for many diseases. However, unintended exposure to drugs in the manufacturing workplace can cause significant health hazards to workers. It is important to protect the workforce from these deleterious effects by limiting exposure to an acceptable level, the occupational exposure limit (OEL). OEL is defined as airborne concentrations (expressed as a time-weighted average for a conventional 8-h workday and a 40-h work week) of a substance to which nearly all workers may be repeatedly exposed (for a working lifetime) without adverse effects. Determination of OELs has become very challenging over time, requiring an overall assessment of the preclinical and clinical data of the drug being manufactured. Previously, to derive OEL values, toxicologists used animal no-observed-adverse-effect level (NOAEL) data, which have been replaced with the overall assessment of animal and human data, placing a higher emphasis on human health-based data. A major advantage of working with human pharmaceuticals is that sufficient clinical data are available for them in most cases. The present manuscript reviews the latest knowledge regarding the derivation of occupational exposure limits as health-based exposure limits (HBELs) for pharmaceuticals. We have provided examples of OEL calculations for various drugs including levofloxacin (CAS No. 100986-85-4), dienogest (CAS no. 65928-58-7), and acetylsalicylic acid (ASA, CAS no. 50-78-2) using human data. This report will benefit professionals in the OEL domain in understanding this highly important, growing, and challenging field.

Pharmacokinetics of levofloxacin mesylate in healthy adult giant panda after single-dose administration via different routes

The pharmacokinetics of levofloxacin mesylate in healthy adult giant panda is unknown. In this study, the pharmacokinetics of levofloxacin after intramuscular administration at a dose of 2 mg/kg and oral administration at a dose of 3 mg/kg in healthy adult giant pandas was determined. Levofloxacin concentrations in plasma were determined using liquid chromatography. In the levofloxacin intramuscular administration group, the absorption and elimination half-lives of the drug were determined to be 0.123 (range: 0.02) hr and 5.402 (range: 0.70) hr, respectively. In the levofloxacin oral administration group, the absorption and elimination half-lives were determined to be 0.325 (range: 0.02) hr and 7.143 (range: 0.63) hr, respectively. Furthermore, the blood-drug concentration of levofloxacin was found to be above 1 μg/ml after 8 hr of intramuscular administration and above 0.5 μg/ml after 12 hr of oral administration. In this study, HPLC conditions and pretreatment methods of plasma samples were optimized and a detection method was established. Our results indicated that in healthy adult giant pandas, levofloxacin was rapidly absorbed and slowly eliminated. This study will therefore provide to be a guide in veterinary research and will be helpful in the rational use of levofloxacin in giant panda.

Assessing the association between fluoroquinolones and emerging adverse drug reactions raised by regulatory agencies: An umbrella review

BACKGROUND

Regulatory agencies warned against fluoroquinolones for the management of minor infections because of the risk of emerging adverse events (collagen-associated adverse events, neuropsychiatric toxicity and long-term disability). We aimed to assess quality and credibility of evidence as well as causality regarding these putative associations.

METHODS

MEDLINE, Scopus, Web of Science and PROSPERO were searched, from inception to August 2019, for systematic reviews with meta-analyses investigating emerging adverse events. Two investigators extracted data to grade quality (through validated AMSTAR-2 tool), rank credibility of the evidence (convincing, highly suggestive, suggestive, weak) through adapted criteria including E-value calculation, and assess causality (Hill's criteria).

RESULTS

Seven systematic reviews of observational studies providing 16 risk estimates [seven, five and four, respectively, for aortic aneurysm/dissection (AAD), retinal detachment (RD) and any tendon disorders (ATD)] met inclusion criteria. No systematic reviews with meta-analysis investigating the risk of neuropsychiatric toxicity or long-term disability were found. The associations between fluoroquinolones and AAD/ATD showed highly suggestive credibility and were supported by strong evidence of causality (double increased risk, especially within first 2 months of treatment). Conflicting data concerning the emergence of RD were retrieved, resulting in weak evidence of causality. Quality of the evidence ranged from high to low for AAD, from moderate to critically low for RD, and it was moderate for ATD.

CONCLUSION

Our analysis supports credible, plausible and highly suggestive associations with AAD (rare occurrence but strong causality) and ATD. Limitations of both umbrella reviews and observational evidence should be considered.

Levofloxacin-induced Desquamation: A Possible and Rare Case Report

Introduction:

Levofloxacin is a fluoroquinolone active against both gram-negative and gram-positive bacteria with a well-defined margin of safety and efficacy. It has various labeled adverse effects like other fluoroquinolones but its adverse effect like desquamation is rarely reported.

Methods:

We present a case report of levofloxacin-induced desquamation in an Indian patient.

Case Report:

A-38-year old female patient presented to the outpatient department, with chief complaints of peeling off her epidermal skin. Initially, Desquamation started on her greater finger, which slowly spread to her hand, feet, lower limbs as well as upper limb and neck region. She was prescribed Levofloxacin for respiratory tract infection.

Results and Discussion:

Considering temporal relationship, upon causality assessment, (Adverse Drug Reaction) ADR was found to be likely, moderate and probable. The drug was withdrawn along with the initiation of supportive therapy and reaction subsided.

Discussion:

Although adverse drug reactions like desquamation are not fatal, this induces anxiety in the patients and reduces patient’s quality of life. This case report will help keep physicians vigilant about the current adverse drug reaction, helping in the early detection and management of ADR.

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.

Rapid and sensitive determination of levofloxacin in microsamples of human plasma by high-performance liquid chromatography and its application in a pharmacokinetic study

A rapid, sensitive and simple high-performance liquid chromatographic assay with ultraviolet detection was developed for the quantification of levofloxacin in microsamples (100 μL) of human plasma. The extraction procedure included a protein precipitation technique and a short chromatographic running time (4.5 min). Analyses were carried out on a Symmetry C18 column using a mixture of acetonitrile and 0.01 m potassium dihydrogen aqueous solution (pH 3.4; 14:86 v/v) as mobile phase. The method provided specificity and was linear (r ≥ 0.9992) over the concentration range 0.1-12 µg/mL. The average absolute recovery was 93.59%. The intra- and inter-day coefficients of variation were <6%. Additionally, levofloxacin was stable in all evaluations. The usefulness of this method was demonstrated in a pharmacokinetic study of levofloxacin in healthy adult volunteers. The present method offers two main advantages: (a) the use of microsamples reduces the total volume of blood to be collected from patients; and (b) it provides a good cost-effectiveness ratio. It is concluded that the method is rapid, simple, sensitive, economical and suitable for the determination of levofloxacin in human plasma using a small volume of sample.

Cefepime

Cefepime (Maxipime), Maxcef, Cepimax, Cepimex, Axepim, a parenteral fourth-generation cephalosporin, is active against many organisms causative in pneumonia. Cefepime has in vitro activity against Gram-positive organisms including Staphylococcus aureus and penicillin-sensitive, -intermediate and -resistant Streptococcus pneumoniae similar to that of cefotaxime and ceftriaxone. Cefepime also has good activity against Gram-negative organisms, including Pseudomonas aeruginosa, similar to that of ceftazidime. Importantly, cefepime is stable against many of the common plasmid- and chromosome-mediated beta-lactamases and is a poor inducer of AmpC beta-lactamases. As a result, it retains activity against Enterobacteriaceae that are resistant to third-generation cephalosporins, such as derepressed mutants of Enterobacter spp. Cefepime may be hydrolyzed by the extended-spectrum beta-lactamases produced by some members of the Enterobacteriaceae, but to a lesser extent than the third-generation cephalosporins. Monotherapy with cefepime 1 or 2g, usually administered intravenously twice daily, was as effective for clinical and bacteriological response as ceftazidime, ceftriaxone or cefotaxime monotherapy (1 or 2g two or three times daily) in a number of randomized, clinical trials in hospitalized adult, or less commonly, pediatric, patients with generally moderate to severe community-acquired or nosocomial pneumonia. More limited data indicated that monotherapy with cefepime 2g three times daily was also as effective in treating patients with nosocomial pneumonia as imipenem/cilostatin 0.5g four times daily, and when combined with amikacin, cefepime was as effective as ceftazidime plus amikacin. Patients with pneumonia who failed to respond to previous antibacterial therapy with penicillins or other cephalosporins responded to treatment with cefepime. Cefepime is generally well tolerated, with a tolerability profile similar to those of other parenteral cephalosporins. In clinical trials, the majority of adverse events experienced by cefepime recipients were mild to moderate and reversible. The most common adverse events with a causal relationship to cefepime reported in clinical trials included rash and diarrhea. Other, less common, adverse events included pruritus, urticaria, nausea, vomiting oral candidiasis, colitis, headache, fever, erythema and vaginitis.

CONCLUSION

Cefepime is an established and generally well tolerated parenteral drug with a broad spectrum of antibacterial activity which, when administered twice daily, provides coverage of most of the pathogens that may be causative in pneumonia. In randomized clinical trials in hospitalized patients with generally moderate to severe community-acquired or nosocomial pneumonia, cefepime monotherapy exhibited good clinical and bacteriological efficacy. Cefepime may become a preferred antibacterial agent for infections caused by Enterobacter spp. With prudent use in order to prevent the emergence of resistant organisms, cefepime will continue to be a suitable option for the empiric treatment of pneumonia.

Staphylococcal skin infections in children: rational drug therapy recommendations

Staphylococcus aureus remains one of the most common and troublesome of bacteria causing disease in humans, despite the development of effective antibacterials and improvement in hygiene. The organism is responsible for over 70% of all skin and soft tissue infections in children and accounts for up to one-fifth of all visits to pediatric clinics. Skin and soft tissue infections that are predominantly caused by S. aureus include bullous and non-bullous impetigo, folliculitis, furunculosis, carbunculosis, cellulitis, surgical and traumatic wound infections, mastitis, and neonatal omphalitis. Other skin and soft tissue infections may also be caused by S. aureus but are often polymicrobial in origin and require special consideration. These include burns, decubitus ulcers (particularly in the perianal region), puncture wounds of the foot, as well as human and mammalian bites. Treatment of staphylococcal skin infections varies from topical antiseptics to prolonged intravenous antibacterials, depending on severity of the lesions and the health of the child. The treatment of choice for oral antibacterials remains the penicillinase-resistant penicillins such as flucloxacillin. Cefalexin and erythromycin are suitable cost-effective alternatives with broader cover, although care must be taken with the use of macrolides because of development of resistance to multiple families of antibacterials, particularly the lincosamides. Other cephalosporins such as cefadroxil and cefprozil are also effective, can be given once daily and have a better tolerability profile -- while azithromycin has a further advantage of a 3-day course. However, all of these agents are more expensive. Although the antibacterials have been given for 10 days in most clinical trials, there is no evidence that this duration is more effective than a 7-day course. In children requiring intravenous therapy, ceftriaxone has a major advantage over other antibacterials such as sulbactam/ampicillin and cefuroxime in that it can be given once daily and may, therefore, be suitable for outpatient treatment of moderate-to-severe skin infections. Newer-generation cephalosporins and loracarbef are also effective and have a broader spectrum of activity, but do not offer any added benefit and are significantly more expensive. Skin and soft tissue infections due to methicillin-resistant S. aureus (MRSA) are still relatively uncommon in children. Well children with community-acquired MRSA infections can be treated with clindamycin or trimethoprim-sulfamethoxazole (cotrimoxazole), but must be observed closely for potentially severe adverse effects. In severe infections, vancomycin remains the treatment of choice, while intravenous teicoplanin and clindamycin are suitable alternatives. Linezolid and quinupristin/dalfopristin are currently showing great promise for the treatment of multi-resistant Gram-positive infections. While the choice of antibacterial is important, supportive management, including removal of any infected foreign bodies, surgical drainage of walled-off lesions, and regular wound cleaning, play a vital role in ensuring cure.

In vivo measurement of levofloxacin penetration into lung tissue after cardiac surgery

Nosocomial pneumonia is a severe complication after cardiac surgery (CS). Levofloxacin, a fluoroquinolone, qualifies for the therapy of postoperative pneumonia. However, penetration properties of levofloxacin into the lung tissue could be substantially affected by CS: atelectasis, low cardiac output after CS, high volume loads, and inflammatory capillary leak potentially influence drug distribution. The aim of our study was to gain information on interstitial antibiotic concentrations in lung tissue in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass. Therefore, six patients undergoing elective CS participated in this prospective study. A dose of 500 mg of levofloxacin was administered intravenously in addition to standard antibiotic prophylaxis immediately after the end of surgery. Time versus concentration profiles of levofloxacin in the interstitial lung tissue and plasma were determined. A microdialysis technique was used for lung interstitial concentration measurements. The microdialysis procedure was well tolerated in all patients and no adverse events were observed. The median area under the concentration curve (AUC) of levofloxacin in interstitial lung fluid was 18.6 microg.h/ml (range, 10.1 to 33.6). The median AUC for tissue (AUC(tissue)) of unbound levofloxacin/AUC(total) in plasma was 0.6 (range, 0.4 to 0.9). The median unbound AUC(tissue)/MIC was 2.4 (range, 1.3 to 4.2) for Pseudomonas aeruginosa. Our study demonstrated the feasibility and safety of microdialysis in human lung tissue in vivo after CS. The unbound AUC/MIC ratio revealed that levofloxacin used in the described manner was borderline sufficient for the treatment of nosocomial pneumonia caused by Klebsiella pneumoniae and insufficient for the treatment of pneumonia caused by Pseudomonas aeruginosa, because the breakpoint of 30 to 40 for AUC/MIC could not be reached by the conventionally used dosage schema in our post-CS setting. Penetration was lower than in previous reports.

Maximizing Pharmacodynamics with High-Dose Levofloxacin

Objective

To review published literature of levofloxacin 750 mg for the treatment of community-acquired pneumonia (CAP), nosocomial-acquired pneumonia (NAP), and skin and skin-structure infections (SSSI) focusing on microbiology, pharmacokinetic, and pharmacodynamic parameters.

Data Sources

MEDLINE was searched for clinical trials and review articles (1966 to September 2004). Also included were data from the manufacturer. Search terms utilized were levofloxacin, pneumonia, skin infections, adverse effects, pharmacokinetics, pharmacodynamics, and resistance.

Study Selection and Data Extraction

All articles and product labeling regarding levofloxacin for the treatment of CAP, NAP, and SSSI were included for review.

Data Synthesis

Compared with the other currently marketed fluoroquinolones, levofloxacin demonstrates similar in vitro activity to a number of commonly identified microorganisms. Levofloxacin 750 mg has shown equivalency to various non-fluoroquinolone regimens for the treatment of NAP and SSSI. Furthermore, a short, 5-day course of levofloxacin 750 mg was similar in efficacy to a longer, 10-day course of levofloxacin 500 mg for the treatment of CAP. Adverse events associated with levofloxacin therapy are dose independent; therefore, the adverse effects seen with high-dose levofloxacin are comparable to lower doses.

Conclusions

The levofloxacin 750 mg dosage formulation is a logical option when evaluating the antimicrobial armamentarium commonly utilized for the empiric treatment of CAP, NAP, and SSSI. Pharmacodynamic parameters are optimized and resistance is minimized when high-dose, short-course therapy is implemented.

Antibiotics and collateral damage

The precarious stability of the normal indigenous flora of the human gastrointestinal tract may be disturbed by a number of factors, but frequently and crucially by antibiotic therapy. This article explores recent insights on the collateral and ecologic effects of antibiotics on the microbiologic flora of the human body and the possible consequences of those effects, which are just beginning to be better understood. New data on this subject will not only help in designing better clinical trials but also begin to answer key questions about collateral damage.

Urinary pharmacokinetics and theoretical pharmacodynamics of intravenous levofloxacin in intensive care unit patients treated with 500 mg b.i.d. for ventilator-associated pneumonia

This study assessed the urinary pharmacokinetics and theoretical pharmacodynamics of levofloxacin in ICU patients treated with 500 mg b.i.d. i.v. for ventilator associated pneumonia to evaluate if this high dosage regimen might ensure appropriate exposure in the treatment of severe UTIs in ICU patients. Nineteen patients (11M, 8F; age, 52 +/- 21 years; weight, 75 +/- 16 kg) presenting with normal renal function (estimated creatinine clearance, 1.83 +/- 0.61 ml/min/kg; diuresis, 1709 +/- 643ml / 24h) were assessed. In steady-state conditions, urine samples were collected at 0-2h, 2-4h, 4-8h and 8-12h during a dosing interval, and urinary concentrations of levofloxacin were assayed by HPLC. Mean (+/- SD) levofloxacin urinary concentrations were 329.1 +/- 159.9, 388.6 +/- 143.5, 266.0 +/- 102.8 and 168.1 +/- 93.3mg/L at 0-2h, 2-4h, 4-8h and 8-12h, respectively, with urinary AUC0-tau of 3171.4 +/- 1192.1mg/L x h. Mean (+/- SD) levofloxacin excretion rates were 44.1 +/- 20.7, 42.8 +/- 8.2, 31.7 +/- 5.8 and 19.8 +/- 4.2 mg/h during the 0-2h, 2-4, 4-8h and 8-12h interval, respectively. Our findings suggest that, consistently with levofloxacin showing high renal excretion as unmodified drug, 500mg b.i.d. i.v. of levofloxacin ensure and maintain urinary concentrations at least 50-fold higher than the MIC90 of most sensitive uropathogens during the overall dosing interval in ICU patients with normal renal function. Considering the major pharmacodynamic determinants for the concentration-dependent bactericidal activity of levofloxacin as applicable at the urinary level (CU/MIC of >12.2 and/or AUC24h U /MIC of >125h), this high dosage regimen may ensure optimal exposure for the treatment of catheter-related and severe lower UTIs not only against sensitive microorganisms, but probably also whenever microorganisms usually considered as intermediate susceptible or resistant to levofloxacin may be involved.

Comparative bactericidal activity of fluoroquinolones against clinical isolates resistant to fluoroquinolones

The bactericidal activity of levofloxacin, ciprofloxacin, moxifloxacin and norfloxacin against clinical isolates conventionally classified as resistant to fluoroquinolones were compared at their maximum concentrations in serum, urine (except moxifloxacin) and bronchial mucosa (except norfloxacin). Time killing curves against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Streptococcus pneumoniae were performed. Serum concentrations of the tested drugs were not able to produce a bactericidal effect on fluoroquinolone-resistant strains. In the urine series, levofloxacin was always bactericidal (decrease > or = 3 logs CFU/ml), while norfloxacin and ciprofloxacin were bactericidal on E. coli (both), P. mirabilis (norfloxacin) and P. aeruginosa (ciprofloxacin). In the bronchial mucosa series, S. pneumoniae was rapidly killed by levofloxacin and moxifloxacin, and K. pneumoniae by levofloxacin after 12 hours. In conclusion, the maximum levofloxacin concentrations achievable at certain body sites allowed killing even of strains defined as resistant by conventional breakpoints.

The expanding role of fluoroquinolones

There has been a growing rate of resistance among common urinary tract pathogens, such as Escherichia coli, to traditional antimicrobial therapies including the "gold standard" trimethoprim-sulfamethoxazole (TMP-SMX). Consequently, fluoroquinolone antimicrobial agents have taken on an expanding management role for UTIs. In fact, the recent Infectious Diseases Society of America clinical management guidelines for UTI recommend fluoroquinolones as first-line therapy for uncomplicated UTI in areas where resistance is likely to be of concern. Fluoroquinolones have demonstrated high bacteriologic and clinical cure rates, as well as low rates of resistance, among most common uropathogens. There are currently 7 fluoroquinolones with indications for UTI in the United States. However, only 3 are commonly used: levofloxacin, ciprofloxacin, and, to a lesser extent, gatifloxacin. Many of the fluoroquinolone agents have once-daily dosing regimens, enhancing patient adherence. In addition, levofloxacin and gatifloxacin have same-dose bioequivalency between their intravenous and oral formulations, allowing for "switch" or step-down therapy from parenteral to oral formulations of the same agent at the same dose. Fluoroquinolones are indicated for the management of acute uncomplicated UTIs, as well as complicated and severe UTI and pyelonephritis, in adults. They are the first-line treatment of acute uncomplicated cystitis in patients who cannot tolerate sulfonamides or TMP, who live in geographic areas with known resistance >10% to 20% to TMP-SMX, or who have risk factors for such resistance. Fluoroquinolone properties include a broad spectrum of coverage, low rates of resistance, and good safety profiles.

IV-to-oral switch therapy for community-acquired pneumonia requiring hospitalization: focus on gatifloxacin

The majority of the 1.1 million patients hospitalized for community-acquired pneumonia (CAP) in the United States begin therapy with an intravenous antibiotic. A switch to oral therapy as soon as patients are clinically stable reduces the length of hospitalization and associated costs. Fluoroquinolones are appropriate candidates for switch therapy. Gatifloxacin is an excellent choice when a fluoroquinolone is being considered for sequential switch therapy in the treatment of CAP requiring hospitalization.

The expanding role of fluoroquinolones

There has been a growing rate of resistance among common urinary tract pathogens, such as Escherichia coli, to traditional antimicrobial therapies including the "gold standard" trimethoprim-sulfamethoxazole (TMP-SMX). Consequently, fluoroquinolone antimicrobial agents have taken on an expanding management role for UTIs. In fact, the recent Infectious Diseases Society of America clinical management guidelines for UTI recommend fluoroquinolones as first-line therapy for uncomplicated UTI in areas where resistance is likely to be of concern. Fluoroquinolones have demonstrated high bacteriologic and clinical cure rates, as well as low rates of resistance, among most common uropathogens. There are currently 7 fluoroquinolones with indications for UTI in the United States. However, only 3 are commonly used: levofloxacin, ciprofloxacin, and, to a lesser extent, gatifloxacin. Many of the fluoroquinolone agents have once-daily dosing regimens, enhancing patient adherence. In addition, levofloxacin and gatifloxacin have same-dose bioequivalency between their intravenous and oral formulations, allowing for "switch" or step-down therapy from parenteral to oral formulations of the same agent at the same dose. Fluoroquinolones are indicated for the management of acute uncomplicated UTIs, as well as complicated and severe UTI and pyelonephritis, in adults. They are the first-line treatment of acute uncomplicated cystitis in patients who cannot tolerate sulfonamides or TMP, who live in geographic areas with known resistance >10% to 20% to TMP-SMX, or who have risk factors for such resistance. Fluoroquinolone properties include a broad spectrum of coverage, low rates of resistance, and good safety profiles.