Levofloxacin

Phototoxicity assessment of drugs and cosmetic products using E. coli

A gram negative bacteria Escherichia coli (Dh5alpha strain) was developed as an alternate test system of phototoxicity. Eight drugs (antibiotics) and cosmetic products (eight face creams) were examined for their phototoxicity using this test system. Five known phototoxic compounds were used to validate the test system. UVA-radiation induced phototoxicity of these compounds was tested by agar gel diffusion assay. Decrease in colony forming units (CFU) was taken as an end point of phototoxicity. The phototoxic compounds and antibiotics produced significant reduction in CFU (p<0.001) at 80 microg/ml concentrations under exposure to UVA-radiation (5.4-10.8 J/cm(2)). One face cream was found phototoxic and produced significant decrease in CFU of E. coli at 1.0mg/ml concentration under UVA exposure (10.8 J/cm(2)). The minimum effective concentration of tetracycline and dose of UVA-radiation were also determined by observing growth inhibition of E. coli through disc diffusion assay. The observations suggested that E. coli can be used as an alternative test system for phototoxicity evaluation of chemicals. A battery of test systems is required to conclude the toxic/phototoxic potential of a chemical agent. In view of the speed, easiness, sensitivity and low cost, E. coli is introduced as one of the alternate test system for phototoxicity studies in safety evaluation of various chemical ingredients or formulations used in cosmetics and drugs.

Drug management in chronic rhinosinusitis: identification of the needs

Chronic rhinosinusitis (CRS) is a group of multifactorial diseases characterized by inflammation of the mucosa of the nose and paranasal sinuses with a history of at least 12 weeks of persistent symptoms despite maximal medical therapy. The precise role played by infection and immunoglobin E (IgE)-mediated hypersensitivity remains unclear. Diagnosis of CRS is based upon medical history, nasal endoscopy and computed tomography scan of the sinuses. The CRS with polyps visible in the middle meatus must be distinguished from the CRS without polyps. Based on the current knowledge about the pathogenesis of CRS, it is admitted that an optimal medical treatment must consider all favorizing factors and control efficaciously the inflammation process. In case of failure of medical treatment, endoscopic sinus surgery should be proposed. However, some well-validated data and scientific evidences are missing, even for the most frequently used medications. After a review of the actual definitions and classifications, a short description of the current knowledge about pathogenesis of CRS is provided in order to justify the actual therapeutic rationales and identify the needs for an effective treatment of CRS.

Clinical efficacy and tolerability of levofloxacin in patients with liver disease: a prospective, non comparative, observational study

The aim of this open, non comparative, observational study was to assess the clinical and bacteriological efficacy, the tolerability and safety of levofloxacin for treatment of concurrent bacterial infections in patients with chronic liver disease. Overall, 40 patients (inpatients or outpatients) were recruited to the study (28 with UTI, 6 with pneumonia, and 6 with spontaneous bacterial peritonitis (SBP)). Patients affected by UTI received 250 mg oral levofloxacin once daily for five days; patients with pneumonia or SBP underwent a 10/14-day therapeutic oral regimen with 500 mg b.i.d. Clinical evaluation and possible side effects were monitored daily both in out- and in-patients. For all patients, laboratory tests were performed at baseline and 3-4 days after the end of therapy in order to evaluate levofloxacin tolerability. Statistical analysis was performed by means of Student's t test to show differences between cases; all values are reported as means and standard deviations and p values were considered as significant when p<0.05. After treatment, clinical cure and bacteriological eradication were achieved in all patients (40/40; 100%). Adverse events, mainly gastrointestinal disturbances (e.g. nausea), were observed in 5 out of 40 patients (12.5%) and no neurotoxic effects were registered (e.g. anxiety, hallucinations, convulsions, mental confusion). No significant variation in laboratory tests due to hematic crasis and/or hepatic and renal disorders was observed. Levofloxacin proved to be highly efficacious and safe in the treatment of bacterial infections in patients affected by liver disease.

Clinical experience in the management of community-acquired pneumonia: lessons from the use of fluoroquinolones

Community-acquired pneumonia (CAP) remains a major cause of morbidity and mortality worldwide. The treatment of CAP has been complicated by several factors, including the expanding spectrum of causative organisms and the rising prevalence of antibiotic resistance among respiratory pathogens. Initial antimicrobial treatment for patients with CAP is usually selected empirically and should provide appropriate coverage against the most common causative organisms, including resistant strains. Respiratory fluoroquinolones, such as levofloxacin, are the only antimicrobials that are highly active against the pathogens most frequently implicated in CAP, including macrolide-resistant and penicillin-resistant pneumococci, Haemophilus influenzae, Legionella spp., and atypical agents. This paper reviews recent studies involving adult patients with CAP that suggest that levofloxacin, as compared with other conventional antibiotic treatments, may be associated with better clinical outcomes.

Comparison of gatifloxacin and levofloxacin administered at various dosing regimens to hospitalised patients with community-acquired pneumonia: pharmacodynamic target attainment study using North American surveillance data for Streptococcus pneumoniae

This work aimed at determining the target attainment potential of gatifloxacin and levofloxacin in specific age-related patient populations such as elderly (> or =65 years) versus younger (<65 years) hospitalised patients with community-acquired pneumonia (CAP). Previously described population pharmacokinetic models of gatifloxacin and levofloxacin administration in patients with serious CAP were utilised to simulate gatifloxacin and levofloxacin pharmacokinetics. Pharmacokinetic simulations and susceptibility data for Streptococcus pneumoniae from the ongoing national surveillance study, Canadian Respiratory Organism Susceptibility Study (CROSS), were then used to produce pharmacodynamic indices of free-drug area under the curve over 24h relative to the minimum inhibitory concentration (free-drug AUC(0-24)/MIC(all)). Monte Carlo simulations were then used to analyse target attainment both of gatifloxacin and levofloxacin to achieve free-drug AUC(0-24)/MIC(all)> or =30 against S. pneumoniae in patients with CAP. Dosing regimens for gatifloxacin were 400 mg once daily (qd) administered to younger patients (<65 years) and gatifloxacin 200 mg qd to elderly patients (> or =65 years). Dosing regimens for levofloxacin were simulated as 500 mg, 750 mg and 1000 mg qd administered to elderly patients as well as younger patients. Monte Carlo simulations using gatifloxacin 400mg against S. pneumoniae yielded probabilities of achieving free-drug AUC(0-24)/MIC(all) of 30 of 96.6% for all patients, 92.3% for younger patients and 97.7% for elderly patients. When administered to elderly patients, a reduced dose of gatifloxacin 200mg qd could achieve a target attainment potential of 91.4%. Monte Carlo simulation using levofloxacin 500 mg qd yielded probabilities of achieving free-drug AUC(0-24)/MIC(all) of 30 of 92.3% for all patients, 95.7% for elderly patients compared with 72.7% for younger patients. Using levofloxacin 750 mg and 1000 mg qd had probabilities of achieving free-drug AUC(0-24)/MIC(all) of 30 of 97.0% and 98.3%, 98.1% and 99.2%, and 90.1% and 95.2% for all patients, elderly patients and younger patients, respectively. The probability of achieving free-drug AUC(0-24)/MIC(all) of 100 was low both with gatifloxacin and levofloxacin, except in the case of elderly patients receiving levofloxacin in a dose of 1000 mg qd (78.5%). We conclude that gatifloxacin and levofloxacin pharmacokinetics in elderly patients with CAP are markedly different from those of younger patients. Higher gatifloxacin/levofloxacin AUC and longer half-life (t(1/2)) values in elderly patients with CAP compared with younger patients provide better pharmacodynamic parameters (free-drug AUC(0-24)/MIC) leading to a higher probability of pharmacodynamic target attainment and improved bacteriological outcome against S. pneumoniae. Gatifloxacin 400mg qd results in a high probability of target attainment and improved bacteriological outcome against S. pneumoniae both in young and elderly CAP patients. However, gatifloxacin administered at a lowered dose of 200 mg qd in elderly patients could still be successful in producing a favourable antibacterial effect. Levofloxacin administered at a dose of 750 mg qd results in a high probability of target attainment and improved bacteriological outcome against S. pneumoniae in all patients with CAP.

Quinolones in 2005: an update

Quinolones are one of the largest classes of antimicrobial agents used worldwide. This review considers the quinolones that are available currently and used widely in Europe (norfoxacin, ciprofloxacin, ofloxacin, levofloxacin and moxifloxacin) within their historical perspective, while trying to position them in the context of recent and possible future advances based on an understanding of: (1) their chemical structures and how these impact on activity and toxicity; (2) resistance mechanisms (mutations in target genes, efflux pumps); (3) their pharmacodynamic properties (AUC/MIC and Cmax/MIC ratios; mutant prevention concentration and mutant selection window); and (4) epidemiological considerations (risk of emergence of resistance, clonal spread). Their main indications are examined in relation to their advantages and drawbacks. Overall, it is concluded that these important agents should be used in an educated fashion, based on a careful balance between their ease of use and efficacy vs. the risk of emerging resistance and toxicity. However, there is now substantial evidence to support use of the most potent drug at the appropriate dose whenever this is required.

Pharmacokinetics of levofloxacin after single intravenous and repeat oral administration to cats

The pharmacokinetic properties of the fluoroquinolone levofloxacin, were investigated in five cats after single intravenous and repeat oral administration at a daily dose of 10 mg/kg. Levofloxacin serum concentration was analyzed by microbiological assay using Klebsiella pneumoniae ATCC 10031 as test microorganism. Serum levofloxacin disposition after intravenous and oral dosing was best fitted to a bicompartmental and a monocompartmental open models with first-order elimination, respectively. After intravenous administration, distribution was rapid (t(1/2(d)) 0.26 +/- 0.18 h) and wide as reflected by the steady-state volume of distribution of 1.75 +/- 0.42 L/kg. Drug elimination was slow with a total body clearance of 0.14 +/- 0.04 L/h.kg and a t(1/2) for this process of 9.31 +/- 1.63 h. The mean residence time was of 12.99 +/- 2.12 h. After repeat oral administration, absorption half-life was of 0.18 +/- 0.12 h and Tmax of 1.62 +/- 0.84 h. The bioavailability was high (86.27 +/- 43.73%) with a peak plasma concentration at the steady state of 4.70 +/- 0.91 microg/mL. Drug accumulation was not significant after four oral administrations. Estimated efficacy predictors for levofloxacin after either intravenous or oral administration indicate a good profile against bacteria with a MIC value below of 0.5 microg/mL. However, for microorganisms with MIC values of 1 microg/mL it would be efficacious only when administered intravenously.

Investigation of the susceptibility trends in Japan to fluoroquinolones and other antimicrobial agents in a nationwide collection of clinical isolates: a longitudinal analysis from 1994 to 2002

The susceptibilities of clinical isolates to fluoroquinolones (FQs) and other antimicrobial agents were surveyed to obtain an accurate understanding of the trends in incidence and antimicrobial resistance. The samples were collected from across Japan, biennially, between 1994 and 2002 and a defined level of resistance to FQ determined. Streptococcus pneumoniae and Haemophilus influenzae exhibited stable and high rates of susceptibility to FQ over the period examined. For methicillin-resistant Staphylococcus aureus the rate of resistance to FQ was 80%-90%, markedly higher than that of methicillin-susceptible S. aureus. The rate of FQ-resistant Escherichia coli increased rapidly to approximately 10% for samples after 2000. Of 696 E. coli isolates collected in 2002, 13 produced an extended-spectrum beta-lactamase (ESBL), with 6 of 13 ESBL-producing isolates being FQ-resistant. No FQ resistance in clinical isolates of Salmonella spp. was detected in any of the surveys. The rate of FQ resistance to Pseudomonas aeruginosa isolated from urinary tract and respiratory tract infections was 40%-60% and 15%-25%, respectively.

In vitro Activity of Levofloxacin against Recent Gram-Negative Nosocomial Pathogens

The objective of our study was to evaluate the in vitro activity of levofloxacin in comparison with other antibiotics (coamoxiclav, ceftriaxone, ceftazidime, meropenem, aztreonam, ciprofloxacin and netilmicin) against about 500 Gram-negative nosocomial microorganisms, isolated during 2003. The bactericidal activities (minimal bactericidal activity and killing curve) of levofloxacin and the other antibiotics were also evaluated. The results confirm the excellent in vitro activity of levofloxacin against multiresistant nosocomial Gram-negative pathogens, including the 73 extended spectrum beta-lactamase producer strains (90% of Escherichia coli, Enterobacter cloacae and Klebsiella pneumoniae were inhibited at 0.5 mg/l). Of particular interest is its susceptibility and bactericidal activity against Stenotrophomonas maltophilia strains. In conclusion, due to the favorable pharmacokinetics and pharmacodynamics of the molecule, associated with its safety, levofloxacin may represent a valid therapeutic option in the treatment of severe Gram-negative nosocomial infections.

Pharmacodynamic target attainment analysis against Streptococcus pneumoniae using levofloxacin 500 mg, 750 mg and 1000 mg once daily in plasma (P) and epithelial lining fluid (ELF) of hospitalized patients with community acquired pneumonia (CAP)

The pharmacokinetics and pharmacodynamics of levofloxacin in patients with respiratory infections such as community-acquired pneumonia (CAP) are poorly documented. This work aimed at assessing the pharmacodynamic target attainment against Streptococcus pneumoniae using levofloxacin 500 mg, 750 mg and 1000 mg administered once daily in plasma (P) and epithelial lining fluid (ELF) of hospitalized patients with community acquired pneumonia. The pharmacokinetics of levofloxacin in elderly (>/=65 years) compared with younger patients (<65 years) hospitalized with CAP were simulated. Susceptibility data with S. pneumoniae from our ongoing national surveillance study (Canadian Respiratory Organism Susceptibility Study-CROSS) were then used to produce pharmacodynamic indices of AUC(0-24)/MIC(all.) Monte Carlo simulations were then used to analyse target attainment of levofloxacin using doses of 500 mg, 750 mg and 1000 mg once daily to achieve free drug AUC(0-24)/MIC(all) >/= 30-100 versus S. pneumoniae in patients with CAP. Pharmacokinetics of levofloxacin simulated after 500 mg, 750 mg and 1000 mg once daily dosing resulted in levofloxacin volume of distribution: elderly patients = younger patients, while levofloxacin clearance was: elderly patients < younger patients. Levofloxacin t(1/2) values were longer in elderly patients (9.8 +/- 2.5h) than younger patients with CAP (7.4 +/- 2.5h). Free levofloxacin AUC(0-24) as well as AUC(0-24)/MIC(all) for S. pneumoniae were higher in elderly patients than younger patients. Monte Carlo simulation using levofloxacin 500 mg yielded probabilities of achieving free-drug AUC(0-24)/MIC(all) of 30 in P and ELF (95.7% and 98.1%) in elderly and younger patients (72.7% and 80.6%) respectively. Levofloxacin 750 mg and 1000 mg once daily had probability of achieving free-drug AUC(0-24)/MIC(all) of 30 in P/ELF of 98.1%/98.6% and 99.2%/99.0%, respectively, in elderly patients compared with 89.9%/94.1% and 95.2%/96.5%, respectively, for younger patients. Probability of achieving of AUC(0-24)/MIC(all) of 100 in P or ELF was very low in both patient populations at different doses except in the case of elderly patients receiving levofloxacin in a dose of 1000 mg once daily P/ELF of 78.5%/87.0%. We conclude that levofloxacin pharmacokinetics in elderly patients with CAP are markedly different from those of younger patients. Levofloxacin 750 mg OD provides high probabilities of achieving free-drug AUC(0-24)/MIC(all) of 30 in both plasma and epithelial lining fluid in patients with CAP including younger patients. Levofloxacin 500 mg OD provides high probabilities of achieving free-drug AUC(0-24)/MIC(all) of 30 in elderly patients with CAP, although we favour the 750 mg dosing in these patients as well. Levofloxacin 750 mg OD results in high probability of pharmacodynamic target attainment and improved bacteriological outcome against S. pneumoniae in patients with CAP.

An economic and outcomes assessment of first-line monotherapy in the treatment of community-acquired pneumonia within managed care

OBJECTIVE

To evaluate the resource consumption and outcomes associated with first-line monotherapy for community-acquired pneumonia, focusing specifically on the use of erythromycin, azithromycin, clarithromycin, and levofloxacin.

STUDY DESIGN

Retrospective managed care database analysis.

PATIENTS AND METHODS

Subjects included patients within a managed care setting over 18 years of age with an initial diagnosis of community-acquired pneumonia from January 1995 to April 2002. Multivariate linear and logistic regression models were used to examine associations with treatment success rates and direct medical costs between antibiotic treatments after controlling for patient demographics and pneumonia risk factors.

MAIN RESULTS

Overall, treatment success rates were high (95.8%), the use of second antibiotics was un common (2.3%), and hospitalizations were infrequent (2.0%) among the 1952 subjects studied. After controlling for patient characteristics and risk factors, significantly lower total costs were associated with erythromycin (92.7% lower, p < 0.001), azithromycin (48.7% lower, p < 0.001), and clarithromycin (21.3% lower, p = 0.015) relative to levofloxacin, with no difference in treatment success between groups. Among newer agents, azithromycin (49.2% lower, p < 0.001) and clarithromycin (21.7% lower, p = 0.013) treatment groups were associated with significantly lower total costs than levofloxacin in the full sample. However, in subjects with a chronic disease score above the sample's mean, only azithromycin was associated with significantly lower total costs (47.9% lower, p < 0.001) relative to levofloxacin.

CONCLUSION

Erythromycin, azithromycin, and clarithromycin were associated with significantly lower total costs than levofloxacin, although treatment success rates did not differ between groups. Following stratification based upon various subset criteria, erythromycin and azithromycin were observed to have significantly lower total costs than levofloxacin. Although these findings may augment clinical guidelines and evidence-based approaches, health plans should consider evaluating their own patient data to see if similar differences exist in their populations.

Comparative assessment of ocular tissue distribution of drug-related radioactivity after chronic oral administration of 14C-levofloxacin and 14C-chloroquine in pigmented rats

Fluoroquinolones have been reported to have a high affinity for melanin. The ocular tissue distribution and accumulation of radioactivity was compared after repeated oral administration of 14C-levofloxacin and 14C-chloroquine at daily doses of 20 mg (0.054 mmol) kg(-1) and 28 mg (0.054 mmol) kg(-1), respectively, in pigmented rats for 84 days. The mean serum level at 24 h following each dose of 14C-levofloxacin was almost constant in the range of 0.33-0.45 nmol equiv mL(-1) after the 14th dose and thereafter. The melanin-containing ocular tissues, such as iris ciliary body and stratum pigment chorioides sclera, showed a much higher concentration of radioactivity than other non-pigmented ocular tissues. The respective concentration in iris ciliary body and stratum pigment chorioides sclera after the 1st dose was 126.47 and 74.91 nmol equiv g(-1), and gradually increased with increasing dose number, reaching 1261.81 and 447.45 nmol equiv g(-1) after the 84th dose, which was ca. 10 and 6 times higher, respectively, than after the 1st dose. The mean serum level following each dose of 14C-chloroquine was almost constant in the range 0.51-0.87 nmol equiv mL(-1) after the 7th dose and thereafter. The respective concentration in iris ciliary body and stratum pigment chorioides sclera after the 1st dose was 572.10 and 709.41 nmol equiv g(-1), and gradually increased with increasing dose number, reaching 33 317.92 and 12 322.90 nmol equiv g(-1) after the 84th dose, which was ca. 58 and 17 times higher, respectively, than after the 1st dose. The concentration in aqueous humour, cornea, lens, vitreous body and retina after the 84th dose was 1.84, 6.33, 0.48, 5.60 and 11.42 nmol equiv g(-1) for 14C-levofloxacin and 18.84, 264.99, 27.26, 158.43 and 1020.89 nmol equiv g(-1) for 14C-chloroquine (ca. 10, 42, 57, 28 and 89 times higher, respectively, than for 14C-levofloxacin). Especially, the concentration in the retina was markedly higher after 14C-chloroquine administration than after 14C-levofloxacin administration. The concentration and the extent of accumulation of radioactivity not only in melanin-containing ocular tissues but also in other non-pigmented ocular tissues, such as retina, after chronic oral administration of 14C-levofloxacin once daily for 84 days were much lower than those after multiple dosing with 14C-chloroquine under the same conditions. These results indicate that levofloxacin would have a much lower risk for ocular toxicity than chloroquine after chronic dosing.

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.

Levofloxacin disposition in cerebrospinal fluid in patients with external ventriculostomy

In vitro levofloxacin exhibits both potent or intermediate activity against most of the pathogens frequently responsible for acute bacterial meningitis and synergistic activity with some beta-lactams. Since levofloxacin was shown to penetrate the cerebrospinal fluid (CSF) during meningeal inflammation both in animals and in humans, the disposition of levofloxacin in CSF was studied in 10 inpatients with external ventriculostomy because of communicating hydrocephalus related to subarachnoid occlusion due to cerebral accidents who were treated with 500 mg of levofloxacin intravenously twice a day because of extracerebral infections. Plasma and CSF concentration-time profiles and pharmacokinetics were assessed at steady state. Plasma and CSF levofloxacin concentrations were analyzed by high-pressure liquid chromatography. The peak concentration of levofloxacin at steady state (C(max ss))was 10.45 mg/liter in plasma and 4.06 mg/liter in CSF, respectively, with the ratio of the C(max ss) in CSF to the C(max ss) in plasma being 0.47. The areas under the concentration-time curves during the 12-h dosing interval (AUC(0-tau)s) were 47.69 mg. h/liter for plasma and 33.42 mg. h/liter for CSF, with the ratio of the AUC(0-tau) for CSF to the AUC(0-tau) for plasma being 0.71. The terminal-phase half-life of levofloxacin in CSF was longer than that in plasma (7.02 +/- 1.57 and 5.51 +/- 1.36 h, respectively; P = 0.034). The ratio of the levofloxacin concentration in CSF to the concentration in plasma progressively increased with time, from 0.30 immediately after dosing to 0.99 at the end of the dosing interval. In the ventricular CSF of patients with uninflamed meninges, levofloxacin was shown to provide optimal exposure, which approximately corresponded to the level of exposure of the unbound drug in plasma. The findings provide support for trials of levofloxacin with twice-daily dosing in combination with a reference beta-lactam for the treatment of bacterial meningitis in adults. This cotreatment could be useful both for overcoming Streptococcus pneumoniae resistance and for enabling optimal exposure of the CSF to at least one antibacterial agent for the overall treatment period.

Levofloxacin compared with imipenem/cilastatin followed by ciprofloxacin in adult patients with nosocomial pneumonia: a multicenter, prospective, randomized, open-label study

BACKGROUND

Therapy of nosocomial pneumonia is usually empiric and includes > or = 1 broad-spectrum antimicrobial agent. When considering the use of fluoroquinolones in these difficult-to-treat infections--in which drug delivery to the site of infection may be impaired or organisms with higher minimum inhibitory concentrations may be present--an agent should be chosen whose pharmacodynamics ensure maximal drug exposure. Use of the 750-mg dose of levofloxacin should enhance therapeutic benefit in patients with nosocomial pneumonia.

OBJECTIVE

The goal of this study was to compare the efficacy and safety of levofloxacin 750 mg and imipenem/cilastatin followed by ciprofloxacin in adult patients with nosocomial pneumonia.

METHODS

This was a multicenter, prospective, randomized, open-label trial conducted in North America. Patients were randomly assigned to 1 of 2 treatment arms: levofloxacin 750 mg QD given i.v. and then orally for 7 to 15 days or imipenem/cilastatin 500 mg to 1 g i.v. every 6 to 8 hours, followed by oral ciprofloxacin 750 mg every 12 hours for 7 to 15 days. Adjunctive antibacterial therapy was mandatory in patients with documented or suspected Pseudomonas aeruginosa or methicillin-resistant Staphylococcus aureus infection. The primary predefined outcome measure was the clinical response (cure, improvement, failure, or unable to evaluate) in microbiologically evaluable patients 3 to 15 days after the end of therapy.

RESULTS

The study enrolled 438 adult patients (315 men, 123 women; mean [SD] age, 55.7 [20.04] years). Two hundred twenty patients received levofloxacin, and 218 received the comparator regimen. Demographic and baseline clinical characteristics were similar in the intent-to-treat and clinically evaluable populations. In patients evaluable for microbiologic efficacy, clinical success (cure or improvement) was achieved in 58.1% (54/93) of patients who received levofloxacin, compared with 60.6% (57/94) of patients who received the comparator regimen (95% CI, -12.0 to 17.2). Similar clinical results were seen in patients evaluable for clinical efficacy and in the intent-to-treat population. In the 187 patients evaluable for microbiologic efficacy, eradication was achieved in 66.7% (62/93) of patients receiving levofloxacin and 60.6% (57/94) of patients receiving the comparator regimen (95% CI, -20.3 to 8.3).

CONCLUSION

In this study, levofloxacin was at least as effective and was as well tolerated as imipenem/cilastatin followed by ciprofloxacin in adult patients with nosocomial pneumonia, as demonstrated by comparable clinical and microbiologic success rates.