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Li RC, Zhu ZY. The integration of four major determinants of antibiotic action: bactericidal activity, postantibiotic effect, susceptibility, and pharmacokinetics. J Chemother 2002; 14:579-83. [PMID: 12583549 DOI: 10.1179/joc.2002.14.6.579] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
A functional pharmacokinetic/pharmacodynamic (PK/PD) index that could simultaneously describe three controlling PD variables, i.e., bactericidal activity, postantibiotic effect (PAE), and susceptibility, in relation to pharmacokinetics, was designed using an in vitro kinetic model. Tobramycin was tested against one standard and five clinical strains of Pseudomonas aeruginosa. The organisms showed minimum inhibitory concentrations (MICs) ranging between 1 and >1000 microg/ml. The model allowed antibiotic concentrations to be reduced exponentially from initial concentrations at fixed multiples of MIC. Antibiotic removal was performed when the decreasing concentrations hit the MIC of individual strain to provide a wide range of AUC(>MIC) within an identical frame of AUC(>MIC)/MIC (AUIC) values. Viable counts were measured at antibiotic addition and before/after its removal for bactericidal activity and PAE assessments. A linear relationship was observed between PAE and bactericidal rate constants, though the pattern varied among different strains. Characterization of the exposure (AUC(>MIC))-effect relationships using the Emax model revealed that the less susceptible strains displayed lower Emax and higher EC50 for both antimicrobial effects. By employing the AUIC as a common frame of reference, regression analysis showed a significant linear correlation (p < 0.05) between the mean PAE and bactericidal rate data and, thereby simultaneously defining the four contributing factors of the PK/PD system. It appears that the AUIC, by conveying the pharmacokinetic and susceptibility information, could serve as a PK/PD index in bridging the interdependency of PAE and bactericidal activity. More importantly, the collective assessment of these four factors would allow more optimal evaluation of dosage regimens.
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Affiliation(s)
- R C Li
- Department of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong.
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52
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Bonapace CR, Friedrich LV, Bosso JA, White RL. Determination of antibiotic effect in an in vitro pharmacodynamic model: comparison with an established animal model of infection. Antimicrob Agents Chemother 2002; 46:3574-9. [PMID: 12384367 PMCID: PMC128701 DOI: 10.1128/aac.46.11.3574-3579.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Animal infection models have historically been used to study pharmacodynamic relationships. Similar results could theoretically be produced by using an in vitro pharmacodynamic model as an alternative to animal models. We compared the antibiotic effects of ticarcillin administered in various doses and dosing regimens against Pseudomonas aeruginosa ATCC 27853 under conditions analogous to those previously employed in a neutropenic-mouse thigh infection model (B. Vogelman et al., J. Infect. Dis. 158:831-847, 1988). Ticarcillin dosages of either 96, 192, or 384 mg/day were administered at 1-, 2-, 3-, 4-, 8-, 12-, or 24-h intervals into a two-compartment model in order to duplicate the concentration-time profiles of the animal model. Colony counts were enumerated at 0 and 24 h. Linear regression and sigmoidal maximum-effect (Emax) model fitting were used to assess the relationship between the percentage of time that the concentration remained above the MIC (%T>MIC) or above four times the MIC (%T>4xMIC) and the change in the log(10) CFU per milliliter (Deltalog(10) CFU/ml) in the central and peripheral compartments. Statistical analysis of the Deltalog(10) CFU/ml values was performed for matched regimens of the in vitro and animal models based on the %T>MICs. The slopes of the regression equations of %T>MICs relative to Deltalog(10) CFU/ml values were similar for the in vitro and animal models, but the y intercept was greater with the in vitro model. The Deltalog(10) CFU/ml values of the 0- to 24-h colony counts at equivalent %T>MICs in the two models were not statistically different (P = 0.087). Overall, the peripheral compartment of the in vitro model was a better predictor of effect than the central compartment. This study, which compares pharmacodynamic principles between an in vitro and an animal model, demonstrated similar relationships between %T>MICs and effects.
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Affiliation(s)
- Charles R Bonapace
- Anti-Infective Research Laboratory, College of Pharmacy, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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53
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Zarzuelo A, Lanao JM, López FG, Sánchez-Navarro A. Influence of the infusion rate on disposition of netilmicin in the isolated rat perfused kidney. Eur J Pharm Sci 2002; 16:133-41. [PMID: 12128167 DOI: 10.1016/s0928-0987(02)00079-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A study of the disposition of netilmicin in the isolated rat kidney was carried out in order to establish the influence of the infusion rate on the drug profile in this tissue. A dose of 800 microg administered as a bolus injection or at infusion times of 5, 7.5 and 10 min, respectively, was injected through the afferent cannula into the isolated kidney. Analysis of outflow curves was carried out using different kinetic approaches. Comparison of statistical moments and derived parameters pointed to changes in the distribution process with the infusion rate. In contrast, elimination remained constant, since the extraction coefficient and relative area under the curve values did not change with the infusion rate, although the MTT (mean transit time) and distribution volume decreased for the longest infusion times. The UDF (unit disposition function) profiles were not superimposed for the different infusion rates and combined with the results of the kinetic analysis revealed that the behaviour of netilmicin in the isolated kidney depends on infusion rate. The apparent partition coefficients in renal cortex and medulla showed higher values for the slower perfusion rates. Yet, a progressive decrease in the absolute amount of netilmicin was predicted in the tubular epithelium compartment whereas the residence time tended to increase. The latter phenomenon could account for the higher aminoglycoside nephrotoxicity reported when these drugs are administered over longer infusion times.
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Affiliation(s)
- Aránzazu Zarzuelo
- Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Salamanca, Avda. Campo Charro s/n, 37007, Salamanca, Spain
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54
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Maglio D, Nightingale CH, Nicolau DP. Extended interval aminoglycoside dosing: from concept to clinic. Int J Antimicrob Agents 2002; 19:341-8. [PMID: 11978505 DOI: 10.1016/s0924-8579(02)00030-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Extended-interval aminoglycoside dosing (EIAD), while a relatively recent concept in mainstream clinical practice, actually has its roots in the mid 1970s. Early trial and error approaches of manipulating the dosage regimen to avoid toxicity and improve efficacy have helped to characterize the pharmacodynamic properties of these drugs. The increasing successful use of EIAD and improved understanding of pharmacodynamics has helped this dosing regimen gain acceptance into routine clinical practice. A 1998 United States survey demonstrated that approximately 75% of hospitals have adopted EIAD into routine patient care. However, controversy still exists regarding some aspects of infrequent aminoglycoside administration, such as length of the drug-free interval and patient exclusion criteria. After more than 50 years of experience with the aminoglycosides we continue to learn how to most appropriately use these drugs.
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Affiliation(s)
- Dana Maglio
- Department of Pharmacy Research, Hartford Hospital, CT 06102, USA
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55
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Pinder M, Bellomo R, Lipman J. Pharmacological principles of antibiotic prescription in the critically ill. Anaesth Intensive Care 2002; 30:134-44. [PMID: 12002919 DOI: 10.1177/0310057x0203000203] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The goal of antimicrobial prescription is to achieve effective drug concentrations. Standard antimicrobial dosing regimens are based on research performed often decades ago and for the most part with patients who were not critically ill. More recent insights into antibiotic activity (e.g. the importance of high peak/MIC ratios for aminoglycosides and time above MIC for beta-lactam antibiotics), drug pharmacokinetics (e.g. increased volume of distribution and altered clearances) and the pathogenesis of sepsis (e.g. third space losses and altered creatinine clearances) have made re-evaluation of dosing regimens necessary for the critically ill. The inflammatory response associated with sepsis results in a rapid decrease in serum albumin levels, large fluid shifts and third space losses, initially with a high cardiac output. In turn these changes result in increased creatinine clearance and increased renal drug clearance. Unless these effects are offset by ensuing renal and/or hepatic impairment, with subsequent drug accumulation, antibiotic levels may be too low for optimal efficacy. The institution of continuous renal replacement therapy separately affects antibiotic clearances, and therefore dosing, even further. This article reviews relevant literature and offers principles for more effective and appropriate antibiotic dosing in the critically ill, based on the pharmacokinetic and pharmacodynamic principles of the main antibiotic groups (aminoglyosides, glycopeptides, beta-lactams, carbapenems and quinolones) and knowledge of the pathophysiology of the inflammatory response syndrome. Finally it also provides some guidance on the basic principles of drug prescription for patients receiving continuous renal replacement therapy.
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Affiliation(s)
- M Pinder
- Intensive Care Unit, Sir Charles Gairdner, Perth, WA
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56
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Gottfredsson M, Erlendsdóttir H, Gudmundsson A, Gudmundsson S. Determination of in vitro postantibiotic effects in Staphylococcus aureus and Escherichia coli by [3H]thymidine incorporation. Clin Microbiol Infect 2002; 2:99-104. [PMID: 11866825 DOI: 10.1111/j.1469-0691.1996.tb00213.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Postantibiotic effects (PAE) and control-related effective regrowth time (CERT) of dicloxacillin, vancomycin, rifampin and gentamicin in Staphylococcus aureus and imipenem, gentamicin, tobramycin, doxycycline and rifampin in Escherichia coli were measured by standard viability counting and [3H]thymidine incorporation. For PAE determination, the two methods correlated well; r2=0.821 for S. aureus and r2=0.939 for E. coli. For viable counts below the detection limits of 105 to 106 log10 CFU/mL, the PAE was overestimated by the [3H]thymidine method. Quantitation of CERT by both methods showed a good correlation, r2=0.867 for S. aureus and r2=0.997 for E. coli. Measuring [3H]thymidine incorporation in bacteria is a novel alternative method for the determination of PAE and CERT.
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57
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Cottagnoud P, Gerber CM, Cottagnoud M, Täuber MG. Gentamicin increases the efficacy of vancomycin against penicillin-resistant pneumococci in the rabbit meningitis model. Antimicrob Agents Chemother 2002; 46:188-90. [PMID: 11751132 PMCID: PMC127013 DOI: 10.1128/aac.46.1.188-190.2002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In experimental meningitis a single dose of gentamicin (10 mg/kg of body weight) led to gentamicin levels in around cerebrospinal fluid (CSF) of 4 mg/liter for 4 h, decreasing slowly to 2 mg/liter 4 h later. The CSF penetration of gentamicin ranged around 27%, calculated by comparison of areas under the curve (AUC in serum/AUC in CSF). Gentamicin monotherapy (-1.24 log(10) CFU/ml) was inferior to vancomycin monotherapy (-2.54 log(10) CFU/ml) over 8 h against penicillin-resistant pneumococci. However, the combination of vancomycin with gentamicin was significantly superior (-4.48 log(10) CFU/ml) compared to either monotherapy alone. The synergistic activity of vancomycin combined with gentamicin was also demonstrated in vitro in time-kill assays.
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58
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Beauchamp D, Labrecque G. Aminoglycoside nephrotoxicity: do time and frequency of administration matter? Curr Opin Crit Care 2001; 7:401-8. [PMID: 11805542 DOI: 10.1097/00075198-200112000-00006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Aminoglycosides remains the mainstay in the treatment of gram-negative infections despite their potential oto-and nephrotoxicity although alternatives with equal or better efficacy are available. Several approaches were investigated to decrease aminoglycosides nephrotoxicity. Among them, only the once-daily dosing of aminoglycosides has been brought to the clinic and physicians are now increasingly adopting this approach to reduce the toxicity of these agents. The incidence of aminoglycoside nephrotoxicity can be further reduced in view of the recent data on the circadian variations of their nephrotoxicity. In fact, it has been clearly demonstrated in both experimental animals and humans that the toxicity is maximal when the drug is injected during the rest period compared with the activity period. Thus, injecting aminoglycosides once-daily at the time of the lowest toxicity is actually the most interesting and clinically applicable approach to reduce aminoglycosides toxicity.
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Affiliation(s)
- D Beauchamp
- Centre de Recherche en Infectiologie, and Université Laval, Ste-Foy, Quebec, Canada.
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59
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Ross GH, Hovde LB, Ibrahim YH, Rotschafer JC. In vitro pharmacodynamic analysis of single daily dosing versus conventional dosing of gentamicin administered with penicillin against Enterococcus faecalis. Pharmacotherapy 2001; 21:1479-85. [PMID: 11765301 DOI: 10.1592/phco.21.20.1479.34476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
STUDY OBJECTIVE To compare the effectiveness of single daily dosing (SDD) versus conventional dosing of gentamicin when administered with penicillin to treat enterococcal infections. DESIGN In vitro pharmacodynamic model. SETTING Hospital laboratory. MEASUREMENTS AND MAIN RESULTS A 24-hour in vitro pharmacodynamic model was employed to simulate SDD and 3 times/day dosing of gentamicin, in conjunction with continuously infused penicillin, against Enterococcus faecalis. Duplicate 24-hour kill curves were generated with varying concentrations of penicillin and gentamicin alone and in combination. No difference in the rate of kill was seen between any combination of penicillin and gentamicin. Regrowth occurred only with drug combinations in which penicillin was administered continuously at the minimum inhibitory concentration. Variations in the gentamicin dosing regimen did not affect regrowth. CONCLUSION In the treatment of enterococcal infections, an SDD regimen for gentamicin shows no efficacy benefit compared with conventional dosing.
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Affiliation(s)
- G H Ross
- College of Pharmacy, University of Minnesota, Minneapolis, USA
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60
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Gunderson BW, Ross GH, Ibrahim KH, Rotschafer JC. What do we really know about antibiotic pharmacodynamics? Pharmacotherapy 2001; 21:302S-318S. [PMID: 11714222 DOI: 10.1592/phco.21.18.302s.33905] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antibiotic pharmacodynamics is an evolving science that focuses on the relationship between drug concentration and pharmacologic effect, which is an antibiotic-induced bacterial death that also can manifest as an adverse drug reaction. The pharmacologic action of antibiotics usually can be described as concentration dependent or independent, although such classifications are highly reliant on the specific antibiotic and bacterial pathogen being studied. Quantitative pharmacodynamic parameters, such as ratio of the area under the concentration-time curve during a 24-hour dosing period to minimum inhibitory concentration (AUC0-24:MIC), ratio of maximum serum antibiotic concentration to MIC (Cmax:MIC), and duration of time that antibiotic concentrations exceed MIC (T>MIC), have been proposed as likely predictors of clinical and microbiologic success or failure for different pairings of antibiotic and bacteria. Thus far, most pharmacodynamic data reported have focused on fluoroquinolones, but work has been conducted on vancomycin, beta-lactams, macrolides, aminoglycosides, and other antibiotics. Despite the development of a number of different pharmacodynamic modeling systems, remarkable agreement exists between in vitro, animal, and limited human data. Although still somewhat premature and requiring additional clinical validation, antibiotic pharmacodynamics will likely advance on four fronts: the science should prove to be extremely useful and represent a cost-effective and efficient method to help develop new antibiotics; formulary committees will likely use pharmacodynamic parameters to assist in differentiating antibiotics of the same chemical class in making antibiotic formulary selections; pharmacodynamic principles will likely be used to design optimal antibiotic strategies for patients with severe infections; and limited data to date suggest that the application of pharmacodynamic concepts may limit or prevent the development of antibiotic resistance. The study of antibiotic pharmacodynamics appears to hold great promise and will likely become a routine part of our daily clinical practices.
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Affiliation(s)
- B W Gunderson
- Department of Experimental and Clinical Pharmacology, University of Minnesota College of Pharmacy, Minneapolis 55455, USA
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61
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Abstract
Considering experience acquired in the past years, it seems as though physicians have reached a plateau in the frequency of peritonitis. A peritonitis rate of 1 every 2 patient years may be acceptable. Further reduction of this peritonitis rate will require inordinately large efforts on all fronts. One will have to consider what are the acceptable costs and risks of peritonitis in patients on peritoneal dialysis. New developments in catheter technology, improved connections, better understanding of patient selection and training programs, improved diagnostic and therapeutic methods in the management of peritonitis, and understanding of the infectious and immune processes are eagerly awaited developments.
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Affiliation(s)
- S Vas
- Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
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62
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Oliveira VC, Tejos CR, Hosaka EM, Andrade SC, Araújo M, Vattimo MF. [Influence of dose regimen on gentamycin nephrotoxicity in rats]. Rev Esc Enferm USP 2001; 35:200-4. [PMID: 12053909 DOI: 10.1590/s0080-62342001000200016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The acute renal failure (ARF), that still presents a right mortality rate (50%) can be defined as an abrupt decline of the glomerular filtration, resultant of ischemic or toxicity event. The drugs nephrotoxicity is one of the most frequent cause (27%) of ARF and it is suggested that the interval of administration of the drug can interfere in this side effect, however the best administration regimen is not very well established. This study evaluated the renal function of rats that received gentamicin (100 mg/kg) in one dose or in two doses (2 x 50 mg/kg), by intraperitoneal infusion. The results obtained in this research, indicated that the single infusion of gentamicin determined smaller nephrotoxicity by the reduction of serum concentration of this drug in 24 hours, decreasing the intracellular accumulation of this gentamicin, which is one of the main cellular mechanisms of this renal injury. The single dose treatment regime, otherwise, shows advantages not only related to the nephrotoxicity effect, but also it is relevant to the cost and safety, which can be rationable factors in the administration of this drug.
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63
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Nicolau DP, McNabb J, Lacy MK, Quintiliani R, Nightingale CH. Continuous versus intermittent administration of ceftazidime in intensive care unit patients with nosocomial pneumonia. Int J Antimicrob Agents 2001; 17:497-504. [PMID: 11397621 DOI: 10.1016/s0924-8579(01)00329-6] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A prospective, randomized pilot study was undertaken to compare the efficacy of continuous versus intermittent ceftazidime in ICU patients with nosocomial pneumonia. Ceftazidime was administered either as a 3 g/day continuous infusion (CI) or an intermittent infusion (II) of 2 g every 8 h. In addition, all patients received concomitant once-daily tobramycin. The demographics of the evaluable patients (n = 35) were similar between the groups: age (years), CI 46 +/- 16, II 56 +/- 20; Apache score, CI 14 +/- 4, II 16 +/- 6; time (days) from admission to diagnosis, CI 9 +/- 6, II 9 +/- 6. Clinical efficacy, defined as cure/improvement was similar between groups [n (%), CI 16/17 (94), II 15/18 (83)], while microbiological response was also comparable [n (%), CI 10/13 (76), II 12/15 (80)]. Minimal inhibitory concentrations (MICs) for all isolates were measured throughout the treatment course; there was no development of resistance during therapy for either regimen. While limited clinical data exist, our results suggest that the use of ceftazidime by CI administration maintains clinical efficacy, optimizes the pharmacodynamic profile and uses less antibiotic compared with the standard 2 g every 8 h intermittent dosing regimen.
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Affiliation(s)
- D P Nicolau
- Department of Pharmacy Research, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102, USA.
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64
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Poumarat F, Le Grand D, Philippe S, Calavas D, Schelcher F, Cabanié P, Tessier P, Navetat H. Efficacy of spectinomycin against Mycoplasma bovis induced pneumonia in conventionally reared calves. Vet Microbiol 2001; 80:23-35. [PMID: 11278120 DOI: 10.1016/s0378-1135(00)00379-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sixteen 3-week-old calves were intratracheally inoculated with Mycoplasma bovis. Follow-up consisted of regular bronchoalveolar lavages (BALs) and clinical examinations. Animals were slaughtered from 4 to 21 days after inoculation. Counts were made of the mycoplasmas and other bacteria systematically isolated from the BAL liquids and lung lobes after slaughter. On the 6th day, spectinomycin 20mg/kg was given intramuscularly in three repeated doses at 24h intervals to six randomly chosen calves. All animals had developed a persistent M. bovis infection with a maximum BAL count on the 6th day (start of treatment). Co-occuring Pasteurella multocida infection was found in most animals with a maximum rate on the 14th day. The extent of lung surface lesions varied widely (0-64%) but was greater in the later slaughtered calves. Average counts of M. bovis and P. multocida in the BAL liquids were lower in treated calves than in untreated ones but the difference was not statistically significant. However, M. bovis and P. multocida counts in the lungs of the treated group were significantly lower than in the untreated group (p=0.003 and 0.009, respectively).
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Affiliation(s)
- F Poumarat
- Agence Française de Sécurité Sanitaire des Aliments, Site de Lyon, 31 av. Tony Garnier, F-69364 Cedex 07, Lyon, France.
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65
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DeLisle S, Perl TM. Antimicrobial management measures to limit resistance: A process-based conceptual framework. Crit Care Med 2001; 29:N121-7. [PMID: 11292887 DOI: 10.1097/00003246-200104001-00012] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
To curb the trend toward increasingly resistant microorganisms, we must at least ensure that antibiotics are used in accordance with the best available scientific evidence. Here we review the control and streamlining measures aimed at optimizing the use of antibiotics, placing an emphasis on their demonstrated effectiveness in the intensive care unit environment. Because of their wide variety, the measures have been organized along the process of choosing, dosing, delivering, and then adjusting the initial antibiotics according to the culture results. By clarifying the range of options available, this process-based conceptual framework assists in best adapting a creative mixture of control measures to a particular healthcare system. The framework also facilitates the overview of a proposed multidisciplinary antibiotic management program, thereby helping to secure the administrative and local provider support necessary for its implementation and continued improvement.
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Affiliation(s)
- S DeLisle
- U.S. Veterans Administration Medical Center and the Departments of Internal Medicine and Physiology, University of Maryland, Baltimore, MD, USA
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66
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Angus BJ, Smith MD, Suputtamongkol Y, Mattie H, Walsh AL, Wuthiekanun V, Chaowagul W, White NJ. Pharmacokinetic-pharmacodynamic evaluation of ceftazidime continuous infusion vs intermittent bolus injection in septicaemic melioidosis. Br J Clin Pharmacol 2000; 50:184-91. [PMID: 10930972 PMCID: PMC2014399 DOI: 10.1111/j.1365-2125.2000.00179.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
AIMS Experimental studies have suggested that constant intravenous infusion would be preferable to conventional intermittent bolus administration of beta-lactam antibiotics for serious Gram-negative infections. Severe melioidosis (Burkholderia pseudomallei infection) carries a mortality over 40% despite treatment with high dose ceftazidime. The aim of this study was to measure the pharmacokinetic and pharmacodynamic effects of continuous infusion of ceftazidime vs intermittent bolus dosing in septicaemic melioidosis. METHODS Patients with suspected septicaemic melioidosis were randomised to receive ceftazidime 40 mg kg(-1) 8 hourly by bolus injection or 4 mg kg(-1) h(-1) by constant infusion following a 12 mg kg(-1) priming dose and pharmacokinetic and pharmacodynamic parameters were compared. RESULTS Of the 34 patients studied 16 (59%) died. Twenty patients had cultures positive for B. pseudomallei of whom 12 (60%) died. The median MIC90 of B. pseudomallei was 2 mg l(-1), giving a minimum target concentration (4*MIC) of 8 mg l(-1). The median (range) estimated total apparent volume of distribution, systemic clearance and terminal elimination half-lives of ceftazidime were 0.468 (0.241-0. 573) l kg(-1), 0.058 (0.005-0.159) l kg(-1) h(-1) and 7.74 (1.95-44.71) h, respectively. Clearance of ceftazidime and creatinine clearance were correlated closely (r = 0.71; P < 0.001) and there was no evidence of significant nonrenal clearance. CONCLUSIONS Simulations based on these data and the ceftazidime sensitivity of the B. pseudomallei isolates indicated that administration by constant infusion would allow significant dose reduction and cost saving. With conventional 8 h intermittent dosing to patients with normal renal function, plasma ceftazidime concentrations could fall below the target concentration but this would be unlikely with a constant infusion. Correction for renal failure, which is common in patients with meliodosis is Clearance = k(*) creatinine clearance where k = 0.72. Calculation of a loading dose gives median (range) values of loading dose, DL of 18.7 mg kg(-1) (9.5-23) and infusion rate I = 3.5 mg k(-1) h(-1) (0.4-13) (which equals 84 mg kg(-1) day(-1)). A nomogram for adjustment in renal failure is given.
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Affiliation(s)
- B J Angus
- Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand
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67
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Affiliation(s)
- M N Swartz
- Massachusetts General Hospital, Boston, Massachusetts 02114, USA. Mswartz.@partners.org
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68
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69
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Angus BJ, Smith MD, Suputtamongkol Y, Mattie H, Walsh AL, Wuthiekanun V, Chaowagul W, White NJ. Pharmacokinetic-pharmacodynamic evaluation of ceftazidime continuous infusion vs intermittent bolus injection in septicaemic melioidosis. Br J Clin Pharmacol 2000; 49:445-52. [PMID: 10792202 PMCID: PMC2014958 DOI: 10.1046/j.1365-2125.2000.00179.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS Experimental studies have suggested that constant intravenous infusion would be preferable to conventional intermittent bolus administration of beta-lactam antibiotics for serious Gram-negative infections. Severe melioidosis (Burkholderia pseudomallei infection) carries a mortality of 40% despite treatment with high dose ceftazidime. The aim of this study was to measure the pharmacokinetic and pharmacodynamic effects of continuous infusion of ceftazidime vs intermittent bolus dosing in septicaemic melioidosis. METHODS Patients with suspected septicaemic melioidosis were randomised to receive ceftazidime 40 mg kg-1 8 hourly by bolus injection or 4 mg kg-1 h-1 by constant infusion following a 12 mg kg-1 priming dose to perform estimation of pharmacokinetic and pharmacodynamic parameters. RESULTS Of the 34 patients studied 16 (59%) died. Twenty patients had cultures positive for B. pseudomallei of whom 12 (60%) died. The median MIC90 of B. pseudomallei was 2 mg l-1, giving a target concentration CT, of 8 mg l-1. The median (range) estimated total apparent volume of distribution, systemic clearance and terminal elimination half-lives of ceftazidime were 0.468 (0.241-0.573) l kg-1, 0.058 (0.005-0.159) l kg-1 h-1 and 7.74 (1.95-44.71) h, respectively. Clearance of ceftazidime and creatinine clearance were correlated closely (r = 0. 71; P < 0.001) and there was no evidence of significant nonrenal clearance. CONCLUSIONS Simulations based on these data and the ceftazidime sensitivity of the B. pseudomallei isolates indicated that administration by constant infusion would allow significant dose reduction and cost saving. With conventional 8 h intermittent dosing to patients with normal renal function, plasma ceftazidime concentrations could fall below the target concentration but this would be unlikely with a constant infusion. Correction for renal failure which is common in these patients is Clearance = k * creatinine clearance where k = 0.072. Calculation of a loading dose gives median (range) values of loading dose, DL of 3.7 mg kg-1 (1. 9-4.6) and infusion rate I = 0.46 mg kg h-1 (0.04-1.3) (which equals 14.8 mg kg-1 day-1). A nomogram for adjustment in renal failure is given.
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Affiliation(s)
- B J Angus
- Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand
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70
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Pea F, Poz D, Baraldo M, Furlanut M. Optimisation of Vancomycin Regimen in Neutropenic Haematological Patients with Normal Renal Function. Clin Drug Investig 2000. [DOI: 10.2165/00044011-200019030-00006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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71
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Majtánová L, Majtán V. Postantibiotic effects of gentamicin and netilmicin on Serratia marcescens: effects on hydrophobicity and motility. Folia Microbiol (Praha) 2000; 45:45-9. [PMID: 11200671 DOI: 10.1007/bf02817449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The impact of postantibiotic effect (PAE) of aminoglycosides (gentamicin, netilmicin) on cell-surface hydrophobicity and motility of a clinical isolate Serratia marcescens was evaluated. For the induction of PAE 2x and 4xMIC concentrations of both antibiotics were used. Gentamicin and netilmicin induced a PAE of similar duration after 2xMIC concentration (2.7 and 2.8 h, respectively). Both aminoglycosides demonstrated concentration-dependent PAE. At a concentration of 4xMIC they produced PAEs of 5.9 and 8.2 h, respectively. The evaluation of hydrophobic properties of S. marcescens after affecting PAE showed that both aminoglycosides inhibited adherence to xylene. This inhibition was also concentration-dependent. More expressive was netilmicin which inhibited the adhesion by 70.5% at 2xMIC and by 85.2% at 4xMIC. Netilmicin inhibited also the adhesion to nitrocellulose filter by 34.7% at 4xMIC. Exposure of the bacterial cells to suprainhibitory concentrations of both aminoglycosides resulted only in moderate inhibition of motility of strain tested compared to the unexposed cells.
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Affiliation(s)
- L Majtánová
- Institute of Preventive and Clinical Medicine, 833 01 Bratislava 37, Slovakia
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72
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Sorger JI, Kirk PG, Ruhnke CJ, Bjornson SH, Levy MS, Cockrin J, Tang P. Once daily, high dose versus divided, low dose gentamicin for open fractures. Clin Orthop Relat Res 1999:197-204. [PMID: 10627736 DOI: 10.1097/00003086-199909000-00026] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A prospective, randomized study was performed on 75 Gustilo Grades II and III open fractures to determine the efficacy of once daily, high dose aminoglycoside therapy, compared with more conventional dosing, in reducing the infection rate when used in conjunction with an aggressive operative treatment protocol. All patients enrolled in the study were treated with immediate irrigation, debridement, operative stabilization of the fracture, and 1 g of cefazolin every 8 hours. At the time of admission patients were randomized to two groups. Patients in Group I received gentamicin 5 mg/kg divided into twice daily doses, and patients in Group II received gentamicin 6 mg/kg given once daily. All patients were monitored for renal toxicity and observed for radiographic and clinical signs of infection until fracture union. The results of the study revealed no statistically significant difference between once daily, high dose versus divided, low dose gentamicin in infection rates. Thus, daily dosing of gentamicin was found to be safe, effective, and cost efficient in the treatment of open fractures when combined with a cephalosporin and aggressive operative debridement and stabilization.
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Affiliation(s)
- J I Sorger
- Department of Orthopaedic Surgery, College of Medicine, University of Cincinnati, OH, USA
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73
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Rybak MJ, Abate BJ, Kang SL, Ruffing MJ, Lerner SA, Drusano GL. Prospective evaluation of the effect of an aminoglycoside dosing regimen on rates of observed nephrotoxicity and ototoxicity. Antimicrob Agents Chemother 1999; 43:1549-55. [PMID: 10390201 PMCID: PMC89322 DOI: 10.1128/aac.43.7.1549] [Citation(s) in RCA: 275] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/1998] [Accepted: 04/05/1999] [Indexed: 11/20/2022] Open
Abstract
The nephrotoxicity and ototoxicity associated with once-daily versus twice-daily administration of aminoglycosides was assessed in patients with suspected or proven gram-negative bacterial infections in a randomized, double-blind clinical trial. Patients who received therapy for >/=72 h were evaluated for toxicity. Patients also received concomitant antibiotics as deemed necessary for treatment of their infection. Plasma aminoglycoside concentrations, prospective aminoglycoside dosage adjustment, and serial audiologic and renal status evaluations were performed. The probability of occurrence of a nephrotoxic event and its relationship to doses and daily aminoglycoside exposure served as the main outcome measurement. One hundred twenty-three patients were enrolled in the study, with 83 patients receiving therapy for at least 72 h. For 74 patients plasma aminoglycoside concentrations were available for analysis, and the patients formed the group evaluable for toxicity. The primary infectious diagnosis for the patients who were enrolled in the study were bacteremia or sepsis, respiratory infections, skin and soft tissue infections, or urosepsis or pyelonephritis. Of the 74 patients evaluable for toxicity, 39 received doses twice daily and 35 received doses once daily and a placebo 12 h later. Nephrotoxicity occurred in 6 of 39 (15.4%) patients who received aminoglycosides twice daily and 0 of 35 patients who received aminoglycosides once daily. The schedule of aminoglycoside administration, concomitant use of vancomycin, and daily area under the plasma concentration-time curve (AUC) for the aminoglycosides were found to be significant predictors of nephrotoxicity by multivariate logistic regression analysis (P = 0.001). The time to a nephrotoxic event was significantly influenced by vancomycin use and the schedule of administration, as assessed by Cox proportional hazards modeling (P = 0.002). The results of the multivariate logistic regression analysis and the Cox proportional hazards modeling demonstrate that both the probability of occurrence and the time to occurrence of aminoglycoside nephrotoxicity are influenced by the schedule on which the aminoglycoside is administered as well as by the concomitant use of vancomycin. Furthermore, this risk of occurrence is modulated by the daily AUC for aminoglycoside exposure. These data suggest that once-daily administration of aminoglycosides has a predictably lower probability of causing nephrotoxicity than twice-daily administration.
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Affiliation(s)
- M J Rybak
- The Anti-Infective Research Laboratory, Department of Pharmacy Services, Detroit Receiving Hospital and University Health Center, College of Pharmacy and Allied Health Professions, Wayne State University, Detroit, Michigan 48201, USA.
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Dworkin RJ. Aminoglycosides for the treatment of gram-negative infections: therapeutic use, resistance and future outlook. Drug Resist Updat 1999; 2:173-179. [PMID: 11504488 DOI: 10.1054/drup.1999.0080] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Ronald J. Dworkin
- Providence Portland Medical Center, Oregon Health Sciences University, Portland, Oregon, USA
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Abstract
OBJECTIVE We developed a simplified gentamicin dosing protocol for all neonates using a loading dose and once-daily dosing that would have an equal or lower incidence of toxicity and an equal or improved effectiveness compared with a regimen with no loading dose that included use of divided daily dosing. METHODS All neonatal intensive care unit patients with a postnatal age </=7 days and started on gentamicin therapy at the discretion of the attending neonatologist were evaluated in this comparative cohort study. All peak and trough serum drug levels (SDL), pertinent demographic data, and markers of potential nephrotoxicity, ototoxicity, and cure were tracked prospectively during 132 consecutive, nonrandomized courses of therapy on a new gentamicin protocol. These were compared with data retrieved retrospectively throughout 103 consecutive, nonrandomized courses of therapy in a control group. RESULTS Initial measured peak SDL were higher (7.8 +/- 1.1 microgram/mL vs 6.1 +/- 1.0 microgram/mL) and trough SDL were lower (0.9 +/- 0.2 microgram/mL vs 2.7 +/- 0.6 microgram/mL) in the protocol term subset, compared with the control term subset (gestational age, >/=37 weeks; weight, >/=2500 g). One hundred percent of the initial and maintenance peak SDL in term protocol neonates were 5 to 12 micrograms/mL; compared with 84% of the initial and 61% of maintenance peak SDL in the term control group. One hundred percent of the initial and maintenance trough SDL were in the desired range of <2 micrograms/mL in term protocol neonates; compared with 70% of the initial and 94% of maintenance trough SDL in the term control group. No significant differences were found in any SDL in low birth weight neonates (gestational age <37 weeks or weight <2500 g and >1500 g) in the protocol compared with the control group. The very low birth weight (weight <1500 g) protocol neonates had a significantly higher mean initial trough SDL (2.3 +/- 0.7 micrograms/mL vs 1.5 +/- 0.6 micrograms/mL) and a lower incidence of initial trough SDL <2.0 micrograms/mL (30% vs 95%) than very low birth weight neonates in the control group. No differences were seen between groups in incidence of significant rise in serum creatinine or failure of hearing screen. CONCLUSION A loading dose followed by once-daily dosing was shown to result in SDL in the safe and therapeutic range in all term neonates in this study. In low birth weight neonates, this regimen resulted in peak and trough SDL throughout therapy that were similar to those observed in the control group. Delaying the initiation of maintenance once-daily dosing until 36 to 48 hours after the loading dose would be expected to result in a higher incidence of initial trough SDL in target range for very low birth weight neonates.
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Affiliation(s)
- F S Lundergan
- Stanford University School of Medicine, Stanford, California, USA.
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76
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Tam VH, Preston SL, Briceland LL. Once-daily aminoglycosides in the treatment of gram-positive endocarditis. Ann Pharmacother 1999; 33:600-6. [PMID: 10369625 DOI: 10.1345/aph.18316] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To examine the role of once-daily aminoglycosides (ODA) in the treatment of gram-positive endocarditis. DATA SOURCES A MEDLINE search was conducted from January 1984 to August 1998, and a Current Contents search was performed from September 1998 to December 1998, using endocarditis or aminoglycoside as key words. In addition, relevant articles were cross-referenced to screen for additional information. DATA EXTRACTION Data published in English regarding the use of aminoglycosides in endocarditis are cited. Emphasis was placed on animal and human studies, but in vitro studies and review articles are also included. DATA SYNTHESIS Endocarditis and the pharmacology of aminoglycosides are briefly reviewed. ODA is an alternative to conventional dosing in the treatment of endocarditis. Extensive work in endocarditis has been done recently in animals and humans to add to our understanding. Limited clinical data exist to support the theoretical advantages of increased efficacy, reduced toxicity, and potential cost savings versus traditional synergistic aminoglycoside dosing. Optimal monitoring of ODA remains undefined. CONCLUSIONS Routine use of ODA for the treatment of endocarditis is not yet advocated. Promising supporting evidence and speculation of success of ODA in gram-positive endocarditis justify well-designed trials to further define its role in therapy.
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Affiliation(s)
- V H Tam
- Albany College of Pharmacy, NY 12208, USA
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77
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Ellepola AN, Samaranayake LP. The in vitro post-antifungal effect of nystatin on Candida species of oral origin. J Oral Pathol Med 1999; 28:112-6. [PMID: 10069538 DOI: 10.1111/j.1600-0714.1999.tb02007.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The post-antifungal effect (PAFE) is defined as the suppression of growth that persists following limited exposure of yeasts to antimycotics and subsequent removal of the drug. Although limited data are available on the PAFE of nystatin on oral isolates of C albicans, there is no information on non-albicans Candida species. As nystatin is the commonest antifungal agent prescribed in dentistry, the main aim of this investigation was to measure the PAFE of oral isolates of Candida belonging to six different species (five isolates each of C. albicans, C. tropicalis, C. krusei, C. parapsilosis, C. glabrata and C. guilliermondii) following limited exposure (1 h) to nystatin. The yeasts were examined for the presence of the PAFE after 1 h exposure to the minimum inhibitory concentration (MIC) of nystatin. The PAFE was determined as the difference in time (h) required for the growth of the drug-free control and the drug-exposed test cultures to increase to the 0.05 absorbance level following removal of the antifungal agent. The mean duration of nystatin-elicited PAFE was lowest for C. albicans (6.85 h) and greatest for C. parapsilosis (15.17 h), while C. krusei (11.58 h), C. tropicalis (12.73 h), C. glabrata (8.51 h), and C. guilliermondii (8.68 h) elicited intermediate values. These findings clarify another intriguing possibility for the persistent, chronic recurrence of oral C. albicans infections despite apparently adequate antifungal drug regimens. The significant variations in nystatin-induced PAFE amongst non-albicans species may also have clinical implications, in terms of nystatin regimens used in the management of these fungal infections.
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Affiliation(s)
- A N Ellepola
- Oral Bio-Sciences Laboratories, Faculty of Dentistry, The Prince Philip Dental Hospital, University of Hong Kong, Hong Kong
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78
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Liu C, Abate B, Reyes M, Gonik B. Single daily dosing of gentamicin: pharmacokinetic comparison of two dosing methodologies for postpartum endometritis. Infect Dis Obstet Gynecol 1999; 7:133-7. [PMID: 10371471 PMCID: PMC1784732 DOI: 10.1002/(sici)1098-0997(1999)7:3<133::aid-idog4>3.0.co;2-h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE We compared the pharmacokinetics of two methods for dosing gentamicin for the treatment of postpartum endometritis with the goal of achieving adequate peak serum concentrations (>12 mg/L) and prolonged trough levels below 2 mg/L. METHODS Group-I subjects (n = 5) received intravenous gentamicin, 5 mg/kg per total body weight over 60 min., with a maximum dose of 500 mg. Group-II subjects (n = 17) were dosed intravenously according to the following formula: Dose = desired peak concentration (fixed at 14 mg/L) * (volume of distribution, i.e., 0.35 L/kg) * adjusted body weight (in kilograms). Serum gentamicin levels were obtained 1 hr. and 8-12 hr. after infusion of the second dose. Pharmacokinetic parameters for the subjects in each group were calculated according to standard formulas. RESULTS Subjects in Group I had significantly higher doses and peak drug concentrations (P < 0.01), while in Group II, 76% of patients had peak levels less than desired (<12 mg/L). Both groups maintained trough levels of <2 mg/L in excess of 12 hr. CONCLUSIONS Changing to the adjusted body weight formula for Group I, while maintaining a dose between 4 and 5 mg/kg, would reduce excessive peak concentrations. Using a calculated volume of distribution of 0.4 L/kg in Group II would improve peak serum concentrations to the desired levels. Both dosing regimens ensure adequate aminoglycoside pharmacokinetic parameters and avoid the need for monitoring serial serum drug concentrations, provided the expected clinical response is also achieved. While the first dosing formula is simpler to calculate, the second dosing formula allows for more individualized dosing considerations.
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Affiliation(s)
- C Liu
- Department of Pharmacy, Detroit Medical Center and Wayne State University, MI, USA
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79
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Liu C, Abate B, Reyes M, Gonik B. Single daily dosing of gentamicin: pharmacokinetic comparison of two dosing methodologies for postpartum endometritis. Infect Dis Obstet Gynecol 1999. [PMID: 10371471 PMCID: PMC1784732 DOI: 10.1002/(sici)1098-0997(1999)7:3<133::aid-idog4>3.0.co;2-h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVE We compared the pharmacokinetics of two methods for dosing gentamicin for the treatment of postpartum endometritis with the goal of achieving adequate peak serum concentrations (>12 mg/L) and prolonged trough levels below 2 mg/L. METHODS Group-I subjects (n = 5) received intravenous gentamicin, 5 mg/kg per total body weight over 60 min., with a maximum dose of 500 mg. Group-II subjects (n = 17) were dosed intravenously according to the following formula: Dose = desired peak concentration (fixed at 14 mg/L) * (volume of distribution, i.e., 0.35 L/kg) * adjusted body weight (in kilograms). Serum gentamicin levels were obtained 1 hr. and 8-12 hr. after infusion of the second dose. Pharmacokinetic parameters for the subjects in each group were calculated according to standard formulas. RESULTS Subjects in Group I had significantly higher doses and peak drug concentrations (P < 0.01), while in Group II, 76% of patients had peak levels less than desired (<12 mg/L). Both groups maintained trough levels of <2 mg/L in excess of 12 hr. CONCLUSIONS Changing to the adjusted body weight formula for Group I, while maintaining a dose between 4 and 5 mg/kg, would reduce excessive peak concentrations. Using a calculated volume of distribution of 0.4 L/kg in Group II would improve peak serum concentrations to the desired levels. Both dosing regimens ensure adequate aminoglycoside pharmacokinetic parameters and avoid the need for monitoring serial serum drug concentrations, provided the expected clinical response is also achieved. While the first dosing formula is simpler to calculate, the second dosing formula allows for more individualized dosing considerations.
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Affiliation(s)
- C Liu
- Department of Pharmacy, Detroit Medical Center and Wayne State University, MI, USA
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80
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Understanding Therapeutic Drug Monitoring. Am J Nurs 1999. [DOI: 10.1097/00000446-199901000-00037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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81
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Ellepola AN, Samaranayake LP. The postantifungal effect (PAFE) of antimycotics on oral C. albicans isolates and its impact on candidal adhesion. Oral Dis 1998; 4:260-7. [PMID: 10200705 DOI: 10.1111/j.1601-0825.1998.tb00290.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Postantifungal effect (PAFE) is defined as the suppression of growth that persists following limited exposure of yeasts to antimycotics and subsequent removal of the drug. As there are no data on the PAFE of oral C. albicans isolates the main aim of this investigation was to measure the PAFE of 10 oral isolates of C. albicans following limited exposure (1 h) to five antifungal drugs, including nystatin which has not been previously used in PAFE assays. A secondary aim of the study was to evaluate the biological significance of PAFE, using a nystatin pre-exposed isolate of C. albicans and observing its adherence to denture acrylic surfaces, during the PAFE period. DESIGN A total of 10 oral isolates of C. albicans were examined for the presence of the PAFE after 1 h exposure to five antifungal drugs, nystatin, amphotericin B, 5-fluorocytosine, ketoconazole and fluconazole. PAFE was automatically assessed with the help of a Spectramax machine which utilizes the principle of periodic turbidometric assessment of growth rates at a given temperature over a given period. The data thus collected are automatically processed in a graphic format as a computer printout. The PAFE was determined as the difference in time (h) required for growth of the drug-free control and the drug-exposed test cultures to increase to 0.05 absorbance level following removal of the antifungal agent (by repeated washing). The adhesion of the single isolate to denture acrylic following limited exposure to nystatin was assessed by a previously described in vitro adhesion assay. RESULTS Significant PAFE were observed for nystatin, amphotericin-B and 5-fluorocytosine. A marginal PAFE was observed for ketoconazole and little or none for fluconazole. The mean duration of the PAFE of nystatin, amphotericin-B, 5-fluorocytosine, ketoconazole and fluconazole were 2.89 (+/- 0.27) h, 2.83 (+/- 0.23) h, 3.18 (+/- 0.31) h, 0.65 (+/- 0.11) h and 0.16 (+/- 0.06) h, respectively. The mean percentage reduction of adhesion of oral C. albicans BU47204 to denture acrylic during the PAFE period following exposure to nystatin for 10, 30, 50, 70 and 90 min was 9.12%, 61.73%, 65.99%, 82.16% and 83.14%, respectively. CONCLUSIONS These in vitro findings imply that even a short period of exposure to antifungals may result in modulation of the growth and the virulent attributes of C. albicans, which however is largely dictated by the antimycotic agent in question. Whether such mechanisms operate in vivo needs to be clarified by further studies.
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Affiliation(s)
- A N Ellepola
- Faculty of Dentistry, University of Hong Kong, Hong Kong
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82
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83
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Gilbert DN, Lee BL, Dworkin RJ, Leggett JL, Chambers HF, Modin G, Täuber MG, Sande MA. A randomized comparison of the safety and efficacy of once-daily gentamicin or thrice-daily gentamicin in combination with ticarcillin-clavulanate. Am J Med 1998; 105:182-91. [PMID: 9753020 DOI: 10.1016/s0002-9343(98)00244-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE The primary purpose of the clinical trial was to assess the safety and efficacy of once-a-day compared with three-times-a-day gentamicin in patients with serious infections who had protocol-determined peak serum aminoglycoside concentrations. PATIENTS AND METHODS A total of 249 hospitalized patients with suspected or proven serious infections were randomized in a 2:2:1 ratio to gentamicin given three times a day with ticarcillin-clavulanate (TC), gentamicin once a day with TC, or ticarcillin-clavulanate (TC) alone. The gentamicin once-a-day dosage for patients with estimated creatinine clearance values of > or =80 mL/min was 5.1 mg/kg. With lower creatinine clearance estimates, the mg/kg dosage of gentamicin was decreased, and the dosage intervals (once daily or three times a day) were maintained. Evaluability required documentation of achievement of protocol-defined peak serum gentamicin levels. RESULTS Of the total 175 evaluable patients, there were no significant differences found between treatment regimens with respect to clinical or microbiologic efficacy. Bedside audiometry proved impractical due to the frequency of altered mental state in ill patients. Based on the traditional increase in serum creatinine values from baseline values, no differences in renal toxicity between the treatment groups was identified. When changes in renal function were reanalyzed based on maintaining, as opposed to worsening, of renal function, preservation of renal function was better in the gentamicin once-a-day patients as opposed to the gentamicin three-times-a-day patients, P <0.01. CONCLUSIONS Gentamicin once a day plus TC, gentamicin three times a day plus TC, and TC alone had similar effects in seriously ill hospitalized patients. The incidence of nephrotoxicity was similar in the three treatment groups. Using a nonvalidated post-hoc analysis, renal function was better preserved in gentamicin once-a-day + TC and TC-only patients as opposed to gentamicin three-times-a-day + TC.
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Affiliation(s)
- D N Gilbert
- Earle A. Chiles Research Institute, Providence Medical Center and Oregon Health Sciences University, Portland, USA
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84
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Vic P, Ategbo S, Turck D, Husson MO, Launay V, Loeuille GA, Sardet A, Deschildre A, Druon D, Arrouet-Lagande C. Efficacy, tolerance, and pharmacokinetics of once daily tobramycin for pseudomonas exacerbations in cystic fibrosis. Arch Dis Child 1998; 78:536-9. [PMID: 9713009 PMCID: PMC1717599 DOI: 10.1136/adc.78.6.536] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To compare once daily with thrice daily tobramycin for treatment of Pseudomonas aeruginosa infection in patients with cystic fibrosis. DESIGN 22 patients with cystic fibrosis, mean (SD) age 11 (3.4) years (range 5.6-19.3), with pulmonary pseudomonas exacerbations were randomly assigned to receive a 14 day course of tobramycin (15 mg/kg/day) either in three infusions (group A) (n = 10) or a single daily infusion (group B) (n = 12), combined with ceftazidime (200 mg/kg/day as three intravenous injections). Efficacy was assessed by comparison of pulmonary, nutritional, and inflammatory indices on days 1 and 14. Cochlear and renal tolerance were assessed on days 1 and 14. Tobramycin concentration was measured in serum and sputum 1, 2, 3, 4, 8, and 24 hours after the start of the infusion. Analysis was by non-parametric Wilcoxon test. RESULTS Variables improving (p < 0.05) in both groups A and B were, respectively: weight/height (+4% and +3.1%), plasma prealbumin (+66 and +63 mg/l), forced vital capacity (FVC) (+14% and +11%), forced expiratory volume in one second (+15% and +14%), and forced expiratory flow between 25% and 75% of FVC (+13% and +21%). Improvement was not significantly different between groups. Renal and cochlear indices remained within the normal range. Serum peak concentration of tobramycin on day 1 was 13.2 (7.1) mg/l in group A and 42.5 (11.2) mg/l in group B (p < 0.001); serum trough was 1.1 (0.8) mg/l in group A and 0.3 (0.2) mg/l in group B (p < 0.01). Tobramycin concentrations in sputum were two to three times higher in group B than group A. CONCLUSIONS Once daily tobramycin combined with three injections of ceftazidime is safe and effective for the treatment of pseudomonas exacerbations in cystic fibrosis patients.
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Affiliation(s)
- P Vic
- Department of Paediatrics, Lille University Hospital, France
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85
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Berkovitch M, Bistritzer T, Aladjem M, Burtin P, Dagan T, Chen-Levi Z, Freedom R, Koren G. Clinical relevance of therapeutic drug monitoring of digoxin and gentamicin in the saliva of children. Ther Drug Monit 1998; 20:253-6. [PMID: 9631920 DOI: 10.1097/00007691-199806000-00003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Digoxin and gentamicin are widely used in pediatric medicine, and therapeutic monitoring is mandatory because of their narrow margin of safety and wide interpatient and intrapatient pharmacokinetic variabilities. Saliva sampling may be of potential interest, especially in children, in whom blood sampling is often difficult. In 11 children treated with digoxin for various cardiac conditions, and in 24 children treated with gentamicin (14 patients were administered gentamicin three times a day, and 10 once-daily), drugs levels were measured in plasma and saliva. There was no correlation between plasma total or free digoxin concentrations and saliva levels, precluding the clinical use of the saliva test for digoxin. No correlation was found between plasma gentamicin concentrations and saliva levels when the drug was administered three times a day; however, good correlation was found when the drug was administered once-daily (r2 = 0.89, p < 0.0001). Saliva may be used as a noninvasive method of measuring gentamicin serum concentrations to guide dosage adjustments in patients administered the drug once-daily.
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Affiliation(s)
- M Berkovitch
- Department of Pediatrics, Assaf Harofeh Medical Center, Zerifin, Israel
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86
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Zembower TR, Noskin GA, Postelnick MJ, Nguyen C, Peterson LR. The utility of aminoglycosides in an era of emerging drug resistance. Int J Antimicrob Agents 1998; 10:95-105. [PMID: 9716286 DOI: 10.1016/s0924-8579(98)00033-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
As the problem of global antibiotic resistance continues to worsen, aminoglycosides have assumed increasing importance in clinical practice. Their broad antimicrobial spectrum, rapid bactericidal action, and ability to act synergistically with other drugs have made them especially useful in the treatment of serious nosocomial infections. However, as with other drugs, their overuse and misuse leads to the development of resistance in important microbial pathogens. The appropriate use of the aminoglycosides is essential to assure their continued efficacy. Therefore, physicians must familiarize themselves with both the clinical indications and the limitations of these drugs if they are to remain efficacious in the years to come.
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Affiliation(s)
- T R Zembower
- Department of Medicine, Northwestern Memorial Hospital and Northwestern University Medical School, Chicago, IL 60611, USA
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87
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Ambrose PG, Owens RC, Quintiliani R, Yeston N, Crowe HM, Cunha BA, Nightingale CH. Antibiotic use in the critical care unit. Crit Care Clin 1998; 14:283-308. [PMID: 9561818 DOI: 10.1016/s0749-0704(05)70396-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The antimicrobial management of patients in the critical care unit is complex. Not only must the clinician be familiar with a number of clinical, microbiological, pharmacological, and epidemiological observations but also fundamental pharmacodynamic concepts. It is an understanding of these concepts that forms the basis for the design of dosing strategies that maximize clinical efficacy and minimize toxicity. Antimicrobial selection is further complicated by the plethora of new antimicrobial agents available with varying clinical utility. Nowhere is this more evident than in the quinolone class of antibiotics. To aid the clinician in differentiating between quinolones it now seems reasonable to create a classification system akin to the generation grouping applied to the cephalosporins. Our classification is based upon the pharmacodynamic principles discussed within this article.
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Affiliation(s)
- P G Ambrose
- Department of Anti-infective Research and Pharmacoeconomic Studies, Hartford Hospital, Connecticut, USA
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88
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Sunyecz JA, Wiesenfeld HC, Heine RP. The pharmacokinetics of once-daily dosing with gentamicin in women with postpartum endometritis. Infect Dis Obstet Gynecol 1998. [PMID: 9812247 PMCID: PMC1784795 DOI: 10.1002/(sici)1098-0997(1998)6:4<160::aid-idog4>3.0.co;2-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE To evaluate the pharmacokinetics and cost of once-daily dosing with gentamicin in women with postpartum endometritis. METHODS Gentamicin in a single daily dose of 4.5 mg/kg was administered intravenously to 10 women with postpartum endometritis. Peak and trough gentamicin levels were measured, and nephrotoxicity and clinical ototoxicity were monitored. Pharmacokinetic data were analyzed, and a cost analysis of once-daily gentamicin administration was performed. RESULTS The mean elimination constant was 0.105 +/- 0.008 L/h, and the mean volume of distribution was 0.34 +/- 0.07 L/kg. Mean peak gentamicin levels exceeded 11 mg/L, and all trough levels were < 0.3 mg/L. Cost savings of 44% were achieved with once-daily dosing of gentamicin, compared with traditional thrice-daily dosing. CONCLUSIONS Once-daily dosing with gentamicin in women with postpartum endometritis achieves therapeutic peak levels without drug accumulation. Substantial cost savings are realized with this dosing regimen.
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Affiliation(s)
- J A Sunyecz
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine/Magee-Womens Research Institute, PA, USA
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89
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Sunyecz JA, Wiesenfeld HC, Heine RP. The pharmacokinetics of once-daily dosing with gentamicin in women with postpartum endometritis. Infect Dis Obstet Gynecol 1998; 6:160-2. [PMID: 9812247 PMCID: PMC1784795 DOI: 10.1002/(sici)1098-0997(1998)6:4<160::aid-idog4>3.0.co;2-c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE To evaluate the pharmacokinetics and cost of once-daily dosing with gentamicin in women with postpartum endometritis. METHODS Gentamicin in a single daily dose of 4.5 mg/kg was administered intravenously to 10 women with postpartum endometritis. Peak and trough gentamicin levels were measured, and nephrotoxicity and clinical ototoxicity were monitored. Pharmacokinetic data were analyzed, and a cost analysis of once-daily gentamicin administration was performed. RESULTS The mean elimination constant was 0.105 +/- 0.008 L/h, and the mean volume of distribution was 0.34 +/- 0.07 L/kg. Mean peak gentamicin levels exceeded 11 mg/L, and all trough levels were < 0.3 mg/L. Cost savings of 44% were achieved with once-daily dosing of gentamicin, compared with traditional thrice-daily dosing. CONCLUSIONS Once-daily dosing with gentamicin in women with postpartum endometritis achieves therapeutic peak levels without drug accumulation. Substantial cost savings are realized with this dosing regimen.
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Affiliation(s)
- J A Sunyecz
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine/Magee-Womens Research Institute, PA, USA
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90
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Matsuo H, Hayashi J, Ono K, Andoh K, Andoh Y, Sano Y, Saruki K, Tanaka J, Yamashita M, Nakamura K, Kubo K. Administration of aminoglycosides to hemodialysis patients immediately before dialysis: a new dosing modality. Antimicrob Agents Chemother 1997; 41:2597-601. [PMID: 9420025 PMCID: PMC164175 DOI: 10.1128/aac.41.12.2597] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We describe a new modality for administering aminoglycosides to hemodialysis (HD) patients, namely, a modification of the once-daily regimen which consists of administering the aminoglycosides over 60 min by drip infusion just before each HD session, with a preplanned peak concentration being reached at the beginning of the session and then with a rapidly decreasing concentration being achieved by the start of HD. The area under the concentration-time curve (AUC), i.e., the accumulation of the drug in the body, is thus minimized by this modality. Arbekacin (ABK) was given at a dose of 2 mg/kg of body weight to 10 HD patients infected with methicillin-resistant Staphylococcus aureus (MRSA) for 2 weeks (six sessions in total), resulting in the complete disappearance of MRSA in 5 patients. A high rate of elimination of ABK was attained for each patient while the patient was on HD (range, 0.20 to 0.42 h-1; mean 0.28 +/- 0.08 h-1) by using high-performance dialyzers provided with membranes made of either polymethylmethacrylate, cellulose triacetate (CTA), or ethylene vinyl alcohol. The best results were obtained with the CTA membrane, as revealed by the overall mass transfer coefficient (Ko). The AUC in the simulation model for the variation in the serum ABK concentration in this modality was calculated to be 40% of that of the conventional post-HD dosing modality, suggesting that a much higher dose could be administered to HD patients who receive HD thrice weekly (4 h per session), giving, e.g., 4 mg/kg initially and before the HD sessions, when there is an interval of 68 h from HD session to HD session, and giving 2 mg/kg before the other sessions.
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Affiliation(s)
- H Matsuo
- Dialysis Center, Hidaka Hospital, Takasaki, Gunma Prefecture, Japan
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91
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Nodoushani M, Nicolau DP, Hitt CM, Quintiliani R, Nightingale CH. Evaluation of Nephrotoxicity Associated with Once-Daily Administration of Aminoglycoside. J Pharm Technol 1997. [DOI: 10.1177/875512259701300613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective: To determine the potential risk factors associated with nephrotoxicity in patients receiving once-daily aminoglycoside (ODA) therapy. Design: Case series. Setting: Large community teaching hospital. Patients: Twenty-five patients considered nephrotoxic during ODA therapy. Main Outcome Measures: This study is a retrospective chart review of patients in whom nephrotoxicity developed during ODA therapy. Nephrotoxicity was defined as a rise in serum creatinine (SCr) concentration of 0.5 mg/dL or more above the preaminoglycoside baseline value. Patients were identified from our institutional ODA database. Based on the previously identified risk factors for aminoglycoside-associated nephrotoxicity with conventional aminoglycoside therapy published by Bertino et al., a data collection tool was developed. Collected data included demographic information, concurrently administered drugs, diagnostic agents used, and potential comorbidity risk factors. Results: Similar to what has been found in patients receiving conventional aminoglycoside regimens, numerous risk factors, such as the concomitant use of cephalosporins, loop diuretics, intravenous contrast dye, angiotensin-converting enzyme inhibitors, and nonsteroidal antiinflammatory drugs, may have been responsible for the rise in SCr observed in our study population. In addition, common comorbidity risk factors in this population were pleural effusion, pneumonia, decrease in systolic blood pressure to less than 80 mm Hg, and preexisting renal disease. Conclusions: Nephrotoxicity is the result of multifactorial processes and is not solely due to the ODA administration technique.
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92
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Mitra AG, Whitten MK, Laurent SL, Anderson WE. A randomized, prospective study comparing once-daily gentamicin versus thrice-daily gentamicin in the treatment of puerperal infection. Am J Obstet Gynecol 1997; 177:786-92. [PMID: 9369820 DOI: 10.1016/s0002-9378(97)70269-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The efficacy, safety, and antibiotic-related charges for once-daily gentamicin with twice-daily clindamycin were compared with those of thrice-daily dosing of these antibiotics. STUDY DESIGN Patients with puerperal endometritis or with chorioamnionitis in labor assessed to be at risk for endometritis were randomized to receive gentamicin 4 mg/kg intravenously every 24 hours with clindamycin 1200 mg intravenously every 12 hours (experimental arm) or gentamicin 1.33 mg/kg intravenously and clindamycin 800 mg intravenously every 8 hours (conventional dosing interval arm). Primary outcomes included cure rates, mean length of treatment, antibiotic-related charges, and nephrotoxicity. Multiple logistic regression analysis was used to control for confounding variables. RESULTS There were 135 and 137 patients randomized to the experimental and conventional interval arms, respectively. Cures were obtained in 94.1% and 87.6% of patients in the experimental and conventional arms, respectively (p = 0.06). The experimental arm had mean antibiotic charges of $250.79 versus $442.49 in the conventional arm (p < 0.0001). There was no permanent nephrotoxicity in either group. CONCLUSIONS Once-daily gentamicin dosing with twice-daily clindamycin dosing is as efficacious and safe as the thrice-daily dosing of gentamicin and clindamycin for peripartum uterine infection. The experimental regimen results in substantial cost savings. The incidence of nephrotoxicity is low.
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Affiliation(s)
- A G Mitra
- Department of Obstetrics and Gynecology, Carolinas Medical Center, Charlotte, North Carolina, USA
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93
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Abstract
Cirrhosis encompasses a range of pathophysiological changes that may alter drug disposition. Drugs that are dependent primarily on the liver for their systemic clearance are more likely to be subject to reduced elimination and subsequent accumulation. Drug accumulation may lead to excessive plasma drug concentrations and adverse effects, if the adverse effects of the drug are concentration-dependent. The effects of hepatic insufficiency on the pharmacokinetics of drugs are not consistent or predictable. Furthermore, the influence of hepatic disease on the disposition of various drugs can vary, even though those drugs may share the same apparent metabolic pathway. Problems in forecasting drug kinetic behaviour are further enhanced by the additional impairment of kidney function (frequently encountered in patients with advanced liver disease) and by the unpredictability of the glomerular filtration rate using customary methods in patients with cirrhosis. Accordingly, dosages are generally adapted empirically, with the help of serum drug concentrations, when applicable. However, drugs eliminated predominantly by hepatic metabolism are not among those most commonly inducing adverse drug reactions or causing severe complications in patients with cirrhosis. Electrolyte disturbances and the hepatorenal syndrome produced by furosemide (frusemide)-the disposition of which is not substantially modified in liver disease-appear to be the most frequent adverse drug reactions in patients with liver disease. Furthermore, clinically significant alterations in the action of medications at concentrations generally considered to be in the normal therapeutic range are not uncommon. Tissue responsiveness to the pharmacological action of some drugs may be modified, as evidenced by the increased susceptibility of the brain in patients with cirrhosis to the action of many psychoactive agents. Another example is the greater susceptibility of such patients to the nephrotoxic potential of aminogly-cosides, which should not be used in this patient group. Drugs may also interfere with adaptive physiological processes induced by liver disease. ACE inhibitors and nonsteroidal anti-inflammatory drugs counteract the enhanced activity of the renin-angiotensin system in advanced liver disease, thereby generating a high risk of excessive hypotension or acute renal failure, respectively. These drugs are best avoided in patients with cirrhosis. Finally, there may be pharmacological effects that overlap with some pathophysiological modifications related to the process of liver disease, such as increased portal pressure produced by some calcium antagonists, or hypoprothrombinaemia related to the inhibition of synthesis of vitamin K-dependent clotting factors by some beta-lactam antibacterials (especially moxalactam and cefamandole). Accordingly, the use of these drugs should be avoided in advanced liver disease. It is noteworthy that reduced drug metabolism in patients with liver disease does not seem to have a significant impact on the frequency of hepatotoxicity. Special caution should be exercised, however, in patients with alcoholic liver disease because excessive alcohol intake may potentiate the hepatotoxic effect of paracetamol (acetaminophen).
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Affiliation(s)
- J F Westphal
- Internal Medicine Service, University Hospitals of Strasbourg, France
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94
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Hayani KC, Hatzopoulos FK, Frank AL, Thummala MR, Hantsch MJ, Schatz BM, John EG, Vidyasagar D. Pharmacokinetics of once-daily dosing of gentamicin in neonates. J Pediatr 1997; 131:76-80. [PMID: 9255195 DOI: 10.1016/s0022-3476(97)70127-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In a prospective, randomized trial of once-daily versus twice-daily intravenous or intramuscular dosing with gentamicin, 11 neonates received 5.0 mg/kg once daily and 15 received 2.5 mg/kg twice daily for 2 ro 3 days. The once-daily intravenous dosing group and the twice-daily intravenous or intramuscular dosing group, respectively, had mean steady-state gentamicin peak concentrations of 10.7 versus 6.6 micrograms/ml (p < 0.05), 6-hour postdosing concentrations of 4.7 versus 2.8 micrograms/ml (p < 0.05), trough concentrations of 1.7 versus 1.7 micrograms/ml, elimination half-life of 8.8 versus 5.4 hours (p < 0.05), and volume of distribution at steady state of 0.67 versus 0.46 L/kg. No nephrotoxic effects were identified in any group. Once-daily gentamicin therapy with 5.0 mg/kg in neonates achieves peak serum levels that are more suitable for optimal bacterial killing than those which traditional regimens achieve. Similar trough levels suggest that even larger doses and longer dosing intervals may be ideal in term neonates.
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Affiliation(s)
- K C Hayani
- Department of Pediatric, University of Illinois, Chicago 60612-7324, USA
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95
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Demczar DJ, Nafziger AN, Bertino JS. Pharmacokinetics of gentamicin at traditional versus high doses: implications for once-daily aminoglycoside dosing. Antimicrob Agents Chemother 1997; 41:1115-9. [PMID: 9145878 PMCID: PMC163859 DOI: 10.1128/aac.41.5.1115] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Two doses of gentamicin (2 and 7 mg/kg of body weight) were administered to 11 healthy volunteers in a randomized, crossover single-dose study to compare their pharmacokinetics. Doses were infused over 1 h with a syringe infusion pump, and 14 concentrations in sera were obtained over an 8-h period. Concentration in serum versus time data were fitted to a two-compartment pharmacokinetic model. In addition, to mimic the clinical setting, subjects' data were fitted by the Sawchuk-Zaske method. Distributional and postdistributional peak concentrations, along with the last obtained concentration in serum, were utilized to compare the following pharmacokinetic variables: volume of distribution at steady state (Vss), half-life, clearance (CL), and maximum concentration in serum (Cmax). With two-compartment pharmacokinetic fitting, significant differences in distribution half-life (average, 21.8 and 41.6 min [P < or = 0.05]) and gentamicin CL (76.6 +/- 6.6 and 67.2 +/- 4.2 ml/min/1.73 m2 [P < or = 0.001]) were found between traditional-dose and high-dose groups, respectively. When the data for concentrations in sera were fitted to a one-compartment pharmacokinetic model by using either the distributional or the postdistributional Cmax, statistically significant differences (P < or = 0.001) were found between Vss, half-life, CL, and Cmax values for both dosage groups. The results show that the pharmacokinetics of gentamicin at a large dose differ significantly from those at the traditional dose. This information has direct implications for once-daily aminoglycoside (ODA) literature when the Cmax values reported are distributional and therefore show falsely high Cmax/MIC ratio estimates. In addition, ODA nomogram dosing tools developed with distributional Cmax values are probably inaccurate.
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Affiliation(s)
- D J Demczar
- Department of Pharmacy Services, Bassett Healthcare, Cooperstown, New York 13326, USA
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96
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97
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Gyssens IC, Knape JT, Van Hal G, ver der Meer JW. The anaesthetist as determinant factor of quality of surgical antimicrobial prophylaxis. A survey in a university hospital. PHARMACY WORLD & SCIENCE : PWS 1997; 19:89-92. [PMID: 9151347 DOI: 10.1023/a:1008691007436] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In actual surgical antimicrobial prophylaxis, the anaesthetist administers the drugs at induction of anaesthesia. In the first phase of our quality-of-use intervention study on antimicrobial drugs in a large university hospital, information on the practice of antimicrobial prophylaxis was needed. The staff of 44 anaesthetists was interviewed by means of a questionnaire. Response rate was 36/44 (82%). The anaesthetists' method of administering surgical prophylaxis was rather uniform and inexpensive: cephalosporins were almost exclusively administered by bolus method. The main reason was that infusion was more cumbersome (range 77-85%). Communication between surgeon and anaesthetist was reported to be poor, and in two out of three operating departments, orders of prophylaxis transmitted at or after induction accounted for more than 80%. Seventy-seven percent of the responders asked the surgeon if prophylaxis was necessary if they were in doubt; 20% responded that they checked it systematically. The data collected by the inquiry proved useful in the process of optimizing surgical prophylaxis in our hospital.
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Affiliation(s)
- I C Gyssens
- Dept. of Ceneral Internal Medicine, University Hospital Nijmegeh, The Netherlands
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98
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Edwards CT, Briggs D, Howes LG. Gentamicin Usage and Monitoring in a Sydney Teaching Hospital. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/jppr1997272133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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99
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Mörike K, Schwab M, Klotz U. Use of aminoglycosides in elderly patients. Pharmacokinetic and clinical considerations. Drugs Aging 1997; 10:259-77. [PMID: 9108987 DOI: 10.2165/00002512-199710040-00003] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Aminoglycosides still represent a mainstay in the treatment of serious infections caused by Gram-negative bacilli in elderly patients. The aging process is accompanied by various physiological changes (e.g. alterations in body composition, impairments in certain organ functions), which may affect drug disposition and, subsequently, drug action. For aminoglycosides that are eliminated by the renal route, kidney function is the key parameter that should be taken into account when dosage regimens are calculated. Because there is a progressive decline in renal function with aging, the glomerular filtration rate should be estimated for each patient. Any change in creatinine clearance (CLCR) should result in a proportional correction of the dosage regimen. Such individualised dosage of aminoglycosides is particularly important because of their narrow therapeutic indices. There are no conclusive data which indicate that age per se affects the elimination of aminoglycoside antibiotics. Overdosage may result from overestimation of renal function if crude serum creatinine (SCr) levels are used as a guide. Nomograms for the relationship between SCr and CLCR have been developed. However, nomograms should be used with caution because substantial interindividual variability in the plasma concentration-clearance relationship is still observed. Therefore, the choice of a maintenance dose based on an assessment of renal function, which change rapidly, should always be considered as preliminary, and verification by serum concentration measurements is necessary. As a result, the use of aminoglycoside serum concentration monitoring during therapy as the most important guide for dosage adjustment is particularly important in the elderly, and is indispensable in conjunction with frequent assessment of renal function. Although a matter of debate, the value of serum concentration monitoring has been demonstrated. With traditional multiple daily dosage, monitoring peak and trough concentrations has been recommended. For once daily dosage, however, no guidelines relating to therapeutic and/or toxic concentrations are available yet. In the meantime, we recommend monitoring at least trough concentrations. Once daily administration of aminoglycosides has emerged as a new mode of treatment. Compared with multiple daily administration, once daily dosage may have a number of advantages, and many clinical trials comparing the efficacy or safety of both modes have shown either superiority or equivalence of the new mode in most indications. At present, however, no data from studies of once daily administration in young compared with elderly adults are available.
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Affiliation(s)
- K Mörike
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
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100
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Ahmed A, París MM, Trujillo M, Hickey SM, Wubbel L, Shelton SL, McCracken GH. Once-daily gentamicin therapy for experimental Escherichia coli meningitis. Antimicrob Agents Chemother 1997; 41:49-53. [PMID: 8980753 PMCID: PMC163658 DOI: 10.1128/aac.41.1.49] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In vitro and in vivo studies have demonstrated that the bacteriologic efficacy of once-daily aminoglycoside therapy is equivalent to that achieved with conventional multiple daily dosing. The impact of once-daily dosing for meningitis has not been studied. Using the well-characterized rabbit meningitis model, we compared two regimens of the same daily dosage of gentamicin given either once or in three divided doses for 24 or 72 h. The initial 1 h mean cerebrospinal fluid (CSF) gentamicin concentration for animals receiving a single dose (2.9 +/- 1.7 micrograms/ml) was threefold higher than that for the animals receiving multiple doses. The rate of bacterial killing in the first 8 h of treatment was significantly greater for the animals with higher concentrations in their CSF (-0.21 +/- 0.19 versus -0.03 +/- 0.22 log10 CFU/ml/h), suggesting concentration-dependent killing. By 24h, the mean reduction in bacterial titers was similar for the two regimens. In animals treated for 72 h, no differences in bactericidal activity was noted for 24, 48, or 72 h. Gentamicin at two different dosages was administered intracisternally to a separate set of animals to achieve considerably higher CSF gentamicin concentrations. In these animals, the rate of bacterial clearance in the first 8 h (0.52 +/- 0.15 and 0.58 +/- 0.15 log10 CFU/ml/h for the lower and higher dosages, respectively) was significantly greater than that in animals treated intravenously. In conclusion, there is evidence of concentration-dependent killing with gentamicin early in treatment for experimental E. coli meningitis, and once-daily dosing therapy appears to be at least as effective as multiple-dose therapy in reducing bacterial counts in CSF.
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Affiliation(s)
- A Ahmed
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235-9063, USA
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