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Kristoffersson AN, Rognås V, Brill MJE, Dishon-Benattar Y, Durante-Mangoni E, Daitch V, Skiada A, Lellouche J, Nutman A, Kotsaki A, Andini R, Eliakim-Raz N, Bitterman R, Antoniadou A, Karlsson MO, Theuretzbacher U, Leibovici L, Daikos GL, Mouton JW, Carmeli Y, Paul M, Friberg LE. Population pharmacokinetics of colistin and the relation to survival in critically ill patients infected with colistin susceptible and carbapenem-resistant bacteria. Clin Microbiol Infect 2020; 26:1644-1650. [PMID: 32213316 DOI: 10.1016/j.cmi.2020.03.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 02/26/2020] [Accepted: 03/15/2020] [Indexed: 02/08/2023]
Abstract
OBJECTIVES The aim was to analyse the population pharmacokinetics of colistin and to explore the relationship between colistin exposure and time to death. METHODS Patients included in the AIDA randomized controlled trial were treated with colistin for severe infections caused by carbapenem-resistant Gram-negative bacteria. All subjects received a 9 million units (MU) loading dose, followed by a 4.5 MU twice daily maintenance dose, with dose reduction if creatinine clearance (CrCL) < 50 mL/min. Individual colistin exposures were estimated from the developed population pharmacokinetic model and an optimized two-sample per patient sampling design. Time to death was evaluated in a parametric survival analysis. RESULTS Out of 406 randomized patients, 349 contributed pharmacokinetic data. The median (90% range) colistin plasma concentration was 0.44 (0.14-1.59) mg/L at 15 minutes after the end of first infusion. In samples drawn 10 hr after a maintenance dose, concentrations were >2 mg/L in 94% (195/208) and 44% (38/87) of patients with CrCL ≤120 mL/min, and >120 mL/min, respectively. Colistin methanesulfonate sodium (CMS) and colistin clearances were strongly dependent on CrCL. High colistin exposure to MIC ratio was associated with increased hazard of death in the multivariate analysis (adjusted hazard ratio (95% CI): 1.07 (1.03-1.12)). Other significant predictors included SOFA score at baseline (HR 1.24 (1.19-1.30) per score increase), age and Acinetobacter or Pseudomonas as index pathogen. DISCUSSION The population pharmacokinetic model predicted that >90% of the patients had colistin concentrations >2 mg/L at steady state, but only 66% at 4 hr after start of treatment. High colistin exposure was associated with poor kidney function, and was not related to a prolonged survival.
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Affiliation(s)
- A N Kristoffersson
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - V Rognås
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - M J E Brill
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Y Dishon-Benattar
- Institute of Infectious Diseases, Rambam Health Care Campus, Haifa, Israel; The Cheryl Spencer Institute for Nursing Research, University of Haifa, Israel
| | - E Durante-Mangoni
- Department of Precision Medicine, University of Campania 'L Vanvitelli' and AORN dei Colli-Monaldi Hospital, Napoli, Italy
| | - V Daitch
- Infectious Diseases University Research Centre, Rabin Medical Centre, Beilinson Hospital, Petah Tikva, Israel; Sackler Faculty of Medicine, Tel-Aviv University, and Department of Medicine E, Rabin Medical Centre, Beilinson Hospital, Petah Tikva, Israel
| | - A Skiada
- First Department of Medicine, Laiko General Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - J Lellouche
- National Centre for Infection Control and Antibiotic Resistance, Tel Aviv Medical Centre, Tel Aviv, Israel; National Laboratory for Antibiotic Resistance and Investigation of Outbreaks in Medical Institutions, Tel Aviv Medical Centre, Tel Aviv, Israel
| | - A Nutman
- National Centre for Infection Control and Antibiotic Resistance, Tel Aviv Medical Centre, Tel Aviv, Israel
| | - A Kotsaki
- 4th Department of Internal Medicine, National and Kapodistrian University of Athens, School of Medicine, University General Hospital Attikon, Athens, Greece
| | - R Andini
- Department of Precision Medicine, University of Campania 'L Vanvitelli' and AORN dei Colli-Monaldi Hospital, Napoli, Italy
| | - N Eliakim-Raz
- Infectious Diseases University Research Centre, Rabin Medical Centre, Beilinson Hospital, Petah Tikva, Israel; Sackler Faculty of Medicine, Tel-Aviv University, and Department of Medicine E, Rabin Medical Centre, Beilinson Hospital, Petah Tikva, Israel
| | - R Bitterman
- Institute of Infectious Diseases, Rambam Health Care Campus, Haifa, Israel; The Ruth and Bruce Rappaport Faculty of Medicine, Techion - Israel Institute of Technology, Haifa, Israel
| | - A Antoniadou
- 4th Department of Internal Medicine, National and Kapodistrian University of Athens, School of Medicine, University General Hospital Attikon, Athens, Greece
| | - M O Karlsson
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | | | - L Leibovici
- Sackler Faculty of Medicine, Tel-Aviv University, and Department of Medicine E, Rabin Medical Centre, Beilinson Hospital, Petah Tikva, Israel; Department of Medicine E, Rabin Medical Centre, Beilinson Hospital, Petah Tikva, Israel
| | - G L Daikos
- First Department of Medicine, Laiko General Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - J W Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, the Netherlands
| | - Y Carmeli
- National Centre for Infection Control and Antibiotic Resistance, Tel Aviv Medical Centre, Tel Aviv, Israel; National Laboratory for Antibiotic Resistance and Investigation of Outbreaks in Medical Institutions, Tel Aviv Medical Centre, Tel Aviv, Israel
| | - M Paul
- Institute of Infectious Diseases, Rambam Health Care Campus, Haifa, Israel; The Ruth and Bruce Rappaport Faculty of Medicine, Techion - Israel Institute of Technology, Haifa, Israel
| | - L E Friberg
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden.
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Theuretzbacher U, Paul M. Developing a new antibiotic for extensively drug-resistant pathogens: the case of plazomicin. Clin Microbiol Infect 2018; 24:1231-1233. [DOI: 10.1016/j.cmi.2018.07.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 10/28/2022]
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Theuretzbacher U. Individualized antibiotic use - an introduction. Int J Infect Dis 2018. [DOI: 10.1016/j.ijid.2018.04.3577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Theuretzbacher U. New drugs – will they solve the problem of resistance to antibiotics? Clin Microbiol Infect 2017; 23:695-696. [DOI: 10.1016/j.cmi.2017.08.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 08/13/2017] [Accepted: 08/15/2017] [Indexed: 10/19/2022]
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Theuretzbacher U. Antibiotic innovation for future public health needs. Clin Microbiol Infect 2017; 23:713-717. [DOI: 10.1016/j.cmi.2017.06.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 06/17/2017] [Accepted: 06/19/2017] [Indexed: 11/30/2022]
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Tängdén T, Ramos Martín V, Felton TW, Nielsen EI, Marchand S, Brüggemann RJ, Bulitta JB, Bassetti M, Theuretzbacher U, Tsuji BT, Wareham DW, Friberg LE, De Waele JJ, Tam VH, Roberts JA. The role of infection models and PK/PD modelling for optimising care of critically ill patients with severe infections. Intensive Care Med 2017; 43:1021-1032. [PMID: 28409203 DOI: 10.1007/s00134-017-4780-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/18/2017] [Indexed: 01/14/2023]
Abstract
Critically ill patients with severe infections are at high risk of suboptimal antimicrobial dosing. The pharmacokinetics (PK) and pharmacodynamics (PD) of antimicrobials in these patients differ significantly from the patient groups from whose data the conventional dosing regimens were developed. Use of such regimens often results in inadequate antimicrobial concentrations at the site of infection and is associated with poor patient outcomes. In this article, we describe the potential of in vitro and in vivo infection models, clinical pharmacokinetic data and pharmacokinetic/pharmacodynamic models to guide the design of more effective antimicrobial dosing regimens. Individualised dosing, based on population PK models and patient factors (e.g. renal function and weight) known to influence antimicrobial PK, increases the probability of achieving therapeutic drug exposures while at the same time avoiding toxic concentrations. When therapeutic drug monitoring (TDM) is applied, early dose adaptation to the needs of the individual patient is possible. TDM is likely to be of particular importance for infected critically ill patients, where profound PK changes are present and prompt appropriate antibiotic therapy is crucial. In the light of the continued high mortality rates in critically ill patients with severe infections, a paradigm shift to refined dosing strategies for antimicrobials is warranted to enhance the probability of achieving drug concentrations that increase the likelihood of clinical success.
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Affiliation(s)
- T Tängdén
- Department of Medical Sciences, Section of Infectious Diseases, Uppsala University, Uppsala, Sweden
| | - V Ramos Martín
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - T W Felton
- Intensive Care Unit, University Hospital of South Manchester, Manchester, UK
| | - E I Nielsen
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - S Marchand
- Inserm U1070, Pole Biologie Santé, Poitiers, France.,UFR Médecine-Pharmacie, Université de Poitiers, Poitiers, France
| | - R J Brüggemann
- Department of Pharmacy, Radboud University Medical Center, Nijmegen, The Netherlands
| | - J B Bulitta
- Center for Pharmacometrics and Systems Pharmacology, College of Pharmacy, University of Florida, Orlando, USA
| | - M Bassetti
- Infectious Diseases Division, Santa Maria della Misericordia University Hospital and University of Udine, Udine, Italy
| | | | - B T Tsuji
- School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, USA
| | - D W Wareham
- Antimicrobial Research Group, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - L E Friberg
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - J J De Waele
- Department of Critical Care Medicine, Ghent University Hospital, Ghent, Belgium
| | - V H Tam
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, USA
| | - Jason A Roberts
- Burns, Trauma and Critical Care Research Centre and Centre for Translational Anti-infective Pharmacodynamics, The University of Queensland, Brisbane, Australia. .,Departments of Intensive Care Medicine and Pharmacy, Royal Brisbane and Women's Hospital, Level 3, Ned Hanlon Building, Herston, Brisbane, QLD, 4029, Australia.
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Theuretzbacher U, Paul M. Revival of old antibiotics: structuring the re-development process to optimize usage. Clin Microbiol Infect 2015; 21:878-80. [PMID: 26119721 DOI: 10.1016/j.cmi.2015.06.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 06/19/2015] [Indexed: 11/18/2022]
Affiliation(s)
| | - M Paul
- Division of Infectious Diseases, Rambam Health Care Campus and Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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Muller AE, Theuretzbacher U, Mouton JW. Use of old antibiotics now and in the future from a pharmacokinetic/pharmacodynamic perspective. Clin Microbiol Infect 2015; 21:881-5. [PMID: 26093075 DOI: 10.1016/j.cmi.2015.06.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 05/31/2015] [Accepted: 06/07/2015] [Indexed: 11/25/2022]
Abstract
Because of the increase in bacterial resistance to commonly used antibacterial drugs, old antibiotics are being 'revived' and, once again, are attracting interest. Many of these old antibiotics were approved long ago, in an era when there was no clear process for development, and requirements for efficacy to be demonstrated in rigorous clinical trials did not exist. At the time of these approvals, pharmacokinetic and pharmacodynamic principles were largely unknown, and did not inform the dose-finding process or recommendations for optimal usage. Indeed, the task of generating basic vital information for these old antibiotics remains to be performed. In this review, we provide a brief overview of the most essential data needed for dose justification and optimization. An overview of the shortage of data for selected old antibiotics illustrates the scope of the problem. In order to prevent harming patients with clinical decisions based on inadequate evidence, a redevelopment procedure for old antibiotics is urgently needed, including a regulatory framework.
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Affiliation(s)
- A E Muller
- Department of Medical Microbiology, Medical Centre Haaglanden (MCH), The Hague, The Netherlands
| | | | - J W Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands; Department of Medical Microbiology, Radboudumc, Nijmegen, The Netherlands.
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Abstract
The global burden of antibiotic resistance is tremendous and, without new anti-infective strategies, will continue to increase in the coming decades. Despite the growing need for new antibiotics, few pharmaceutical companies today retain active antibacterial drug discovery programmes. One reason is that it is scientifically challenging to discover new antibiotics that are active against the antibiotic-resistant bacteria of current clinical concern. However, the main hurdle is diminishing economic incentives. Increased global calls to minimize the overuse of antibiotics, the cost of meeting regulatory requirements and the low prices of currently marketed antibiotics are strong deterrents to antibacterial drug development programmes. New economic models that create incentives for the discovery of new antibiotics and yet reconcile these incentives with responsible antibiotic use are long overdue. DRIVE-AB is a €9.4 million public-private consortium, funded by the EU Innovative Medicines Initiative, that aims to define a standard for the responsible use of antibiotics and to develop, test and recommend new economic models to incentivize investment in producing new anti-infective agents.
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Affiliation(s)
- S Harbarth
- Infection Control Program and Division of Infectious Diseases, University of Geneva Hospitals and Medical Faculty, Geneva, Switzerland
| | | | - J Hackett
- AstraZeneca Research & Development, Gaithersburg, MD, USA
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Paul M, Carmeli Y, Durante-Mangoni E, Mouton JW, Tacconelli E, Theuretzbacher U, Mussini C, Leibovici L. Combination therapy for carbapenem-resistant Gram-negative bacteria. J Antimicrob Chemother 2014; 69:2305-9. [DOI: 10.1093/jac/dku168] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Nation RL, Li J, Cars O, Couet W, Dudley MN, Kaye KS, Mouton JW, Paterson DL, Tam VH, Theuretzbacher U, Tsuji BT, Turnidge JD. Consistent Global Approach on Reporting of Colistin Doses to Promote Safe and Effective Use. Clin Infect Dis 2013; 58:139-41. [DOI: 10.1093/cid/cit680] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Theuretzbacher U. SP26-3 Facilitating new drug development – international actions. Int J Antimicrob Agents 2013. [DOI: 10.1016/s0924-8579(13)70213-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Theuretzbacher U. Pharmacokinetic and Pharmacodynamic Issues for Antimicrobial Therapy in Patients With Cancer. Clin Infect Dis 2012; 54:1785-92. [DOI: 10.1093/cid/cis210] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Abstract
The novel class of echinocandins represents a milestone in antifungal drug research that has further expanded our therapeutic options. The favorable pharmacokinetic profile of the echinocandins has been elucidated in animal and human studies. The echinocandins are targeted for once-daily dosing and are not metabolized through the cytochrome P450 enzyme system, and they are generally well tolerated due to lack of mechanism-based toxicity. Little is known, however, about the disposition of these compounds in tissues and body fluids and the relationships between dosage, concentrations in the body, and antifungal efficacy in vivo. Many unanswered questions remain, including the importance of the high protein binding and the concentrations of free antifungal agents at target sites. Although recent attempts have been made to ensure the reproducibility of in vitro tests, the clinical usefulness of these tests is still unreliable and their relevance remains controversial. In vitro activity must be correlated with achievable concentrations at the site of infection. As little is known about the relationship between the pharmacokinetics and the pharmacodynamics of the echinocandins, increased incorporation of these principles in experimental and clinical studies is an important objective that will benefit the treatment and prophylaxis of life-threatening invasive fungal infections in immunocompromised patients.
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Affiliation(s)
- U Theuretzbacher
- Center for Anti-Infective Agents-Vienna, Eckpergasse 13, 1180 Vienna, Austria.
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Seewald M, Theuretzbacher U. Schneller Erregernachweis bei Vaginalinfektionen. Geburtshilfe Frauenheilkd 2001. [DOI: 10.1055/s-2001-11903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
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Naber KG, Theuretzbacher U, Moneva-Koucheva G, Stass H. Urinary excretion and bactericidal activity of intravenous ciprofloxacin compared with oral ciprofloxacin. Eur J Clin Microbiol Infect Dis 1999; 18:783-9. [PMID: 10614952 DOI: 10.1007/s100960050401] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Twelve healthy volunteers participated in a randomized crossover study to compare urinary concentrations, serum parameters, and urinary bactericidal activity of ciprofloxacin after single intravenous (i.v.) doses of 200 mg and 400 mg and an oral (p.o.) dose of 500 mg. The median serum concentrations at 1 h after administration were 1 microg/ml, 4.3 microg/ml, and 2.2 microg/ml, respectively. Between the first collection period (0-2 h) and the last collection period (38-48 h), the median urinary concentrations decreased from 394 microg/ml, 675 microg/ml, and 585 microg/ml, respectively, to 0.3 microg/ml, 0.6 microg/ml, and 1 microg/ml, respectively. The urinary concentrations after the 400 mg i.v. and the 500 mg p.o. doses were not statistically different but were significantly higher than those after the 200 mg i.v. dose. The urinary bactericidal titers (UBTs), defined as the highest urinary dilution bactericidal for the organism tested, were determined against Escherichia coli (ATCC 25922) and eight uropathogens up to 48 h after administration of ciprofloxacin. The UBTs after the 400 mg i.v. and the 500 mg p.o. doses were similar and were significantly higher (P < 0.05) than those following the 200 mg i.v. dose. After 400 mg i.v. and 500 mg p.o., median UBTs of > or = 1:4 were present up to 48 h for all strains for which the MIC was < or = 0.5 microg/ml, except for one nalidixic-acid resistant Escherichia coli strain for which the MIC was 0.25 microg/ml. Species for which the MIC is > or = 1 microg/ml showed median UBTs of > or = 1:4 for 8-16 h. Median UBTs of > or = 1:4 were present up to 8 and 12 h for both Pseudomonas strains tested. A once-daily dosage of 400 mg i.v. or 500 mg p.o. might be sufficient for treatment of urinary tract infections caused by highly susceptible pathogens. A twice-daily dosing scheme seems to be preferable for complicated infections caused by pathogens with intermediate susceptibilty (MIC > or = 1 microg/ml) or for empiric therapy.
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Affiliation(s)
- K G Naber
- Department of Urology, Hospital St. Elisabeth, Straubing, Germany
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Naber KG, Theuretzbacher U, Kinzig M, Savov O, Sörgel F. Urinary excretion and bactericidal activities of a single oral dose of 400 milligrams of fleroxacin versus a single oral dose of 800 milligrams of pefloxacin in healthy volunteers. Antimicrob Agents Chemother 1998; 42:1659-65. [PMID: 9661000 PMCID: PMC105662 DOI: 10.1128/aac.42.7.1659] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Twelve healthy volunteers participated in this randomized crossover study to compare the concentrations and recovery levels of fleroxacin and pefloxacin in urine and to assess their bactericidal activities against 12 strains of urinary pathogens with different susceptibilities over a wide range of MICs. The volunteers received a single oral dose of 400 mg of fleroxacin or 800 mg of pefloxacin. The mean cumulative renal excretion of unchanged fleroxacin, N-demethyl-fleroxacin, and N-oxide-fleroxacin accounted for 67, 7, and 6% of the total dose, respectively. The total urinary recovery of pefloxacin and the active metabolite norfloxacin was 34%. In the time-kill and the urinary bactericidal titer (UBT) studies, only the subjects' urine not supplemented with broth was used. With most tested organisms and both quinolones it took more than 8 h to achieve a reduction in CFU of 99.9% (3 log units). Overall, there was a good correlation between UBTs and MICs for the strains. Against Escherichia coli ATCC 25922 the median UBTs were similar for both antibiotics and at least 1:8 for 96 h; against the E. coli strain for which the MIC was 0.5 microgram/ml the UBT was at least 1:4 for 48 h. The UBTs of both drugs against Klebsiella pneumoniae were at least 1:16 for 72 h. The UBTs for Staphylococcus aureus (the MIC for which was 16 micrograms/ml) of both antibiotics were low, and in some of the samples, no bactericidal titers were observed. UBTs for Proteus mirabilis of pefloxacin are significantly higher than those of fleroxacin. For Pseudomonas aeruginosa the median UBTs were present for the 24-to-48-h interval. The same is true for Enterococcus faecalis. Against Staphylococcus saprophyticus, UBTs were present for at least 48 h with both quinolones. Overall, a single oral dose of 400 mg of fleroxacin exhibits UBTs comparable to those of 800 mg of pefloxacin. Therefore, it may be expected that half of the dose of fleroxacin gives comparable results in the treatment of urinary tract infections; this should be substantiated in comparative clinical trials.
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Affiliation(s)
- K G Naber
- Department of Urology, St. Elisabeth Hospital, Straubing, Germany
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