151
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Lonsdale DO, Udy AA, Roberts JA, Lipman J. Antibacterial therapeutic drug monitoring in cerebrospinal fluid: difficulty in achieving adequate drug concentrations. J Neurosurg 2012; 118:297-301. [PMID: 23121433 DOI: 10.3171/2012.10.jns12883] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This report illustrates the difficulty in managing CNS infection in neurosurgical patients, the altered drug pharmacokinetics associated with critical illness, and the role that therapeutic drug monitoring (TDM) of CSF can play in assisting clinical decision making. The authors present a case of external ventricular drain-related ventriculitis in a critically ill patient who initially presented with a subarachnoid hemorrhage. They discuss the physiological changes found in such patients, in particular augmented renal clearance (demonstrated in this patient by a measured creatinine clearance of 375 ml/min/1.73 m(2)), noting the effect this had on drug pharmacokinetics and leading to dosing requirements 2-3 times those recommended in standard regimens. The authors consider the bacterial "kill" characteristics of 2 different antibacterial agents (meropenem and vancomycin) and describe the unique approach of using plasma and CSF TDM to achieve optimal drug exposure at the site of infection while limiting toxic side effects. The authors demonstrate that simply using plasma TDM as a surrogate marker for drug concentration in the CNS may lead to underdosing, exemplified in this patient by CSF vancomycin concentrations as little as 13% of that in plasma. Finally, by measuring CSF and plasma ratios, the authors illustrate the disparity in pharmacokinetic properties between drugs, reminding the clinician of the importance of CNS penetration when selecting antibacterial agents in such cases. This work raises an important hypothesis in the accurate prescription of antibacterial agents in neurosurgical critical care, namely underdosing in the context of augmented elimination and impaired target site penetration. However, prior to any recommendations regarding empirical dose modification, more data are clearly needed, particularly with respect to the safety and efficacy of such an approach. In this respect, the authors would advocate further research using TDM in the management of CNS infection in this setting, in addition to work defining plasma and CSF concentrations associated with antibacterial efficacy and toxicity.
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Affiliation(s)
- Dagan O Lonsdale
- Department of Intensive Care Medicine, Royal Brisbane and Women’s Hospital, Herston, Queenslan, Australia
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152
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Mavros MN, Tansarli GS, Vardakas KZ, Rafailidis PI, Karageorgopoulos DE, Falagas ME. Impact of vancomycin minimum inhibitory concentration on clinical outcomes of patients with vancomycin-susceptible Staphylococcus aureus infections: a meta-analysis and meta-regression. Int J Antimicrob Agents 2012; 40:496-509. [PMID: 23068600 DOI: 10.1016/j.ijantimicag.2012.07.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 07/24/2012] [Accepted: 07/27/2012] [Indexed: 12/29/2022]
Abstract
Although the vancomycin minimum inhibitory concentration (VMIC) susceptibility breakpoint for Staphylococcus aureus was recently lowered to ≤2 mg/L, it is argued that isolates in the higher levels of the susceptible range may bear adverse clinical outcomes. Clinical outcomes (all-cause mortality and treatment failure) of patients with S. aureus infections by 'high-VMIC' (conventionally defined as VMIC >1 mg/L but ≤2 mg/L) and 'low-VMIC' (VMIC≤1 mg/L) isolates were compared by performing a systematic review and meta-analysis. The effect of potential confounders was assessed by univariate meta-regression analyses. In total, 33 studies (6210 patients) were included. Most studies were retrospective (28/33), used the Etest (22/33) and referred to meticillin-resistant S. aureus (MRSA) infections (26/33) and bacteraemia (23/33). Irrespective of VMIC testing method, meticillin resistance and site of infection, the high-VMIC group had higher mortality [relative risk (RR)=1.21 (95% confidence interval 1.03-1.43); 4612 patients] and more treatment failures [RR=1.67 (1.26-2.21); 2049 patients] than the low-VMIC group. The results were not affected by the potential confounders and were reproduced in the subset of patients with MRSA infections [mortality, RR=1.19 (1.02-1.40), 2956 patients; treatment failure, RR=1.69 (1.26-2.25), 1793 patients]. In conclusion, infection by vancomycin-susceptible S. aureus with VMIC>1mg/L appears to be associated with higher mortality than VMIC≤1mg/L. Further research is warranted to verify these results and to assess the impact of VMIC on meticillin-susceptible S. aureus infections. Evaluation of alternative antimicrobial agents also appears justified.
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153
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154
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Does resistance in severe infections caused by methicillin-resistant Staphylococcus aureus give you the ‘creeps’? Curr Opin Crit Care 2012; 18:451-9. [PMID: 22941206 DOI: 10.1097/mcc.0b013e3283578968] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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155
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Wunderink RG, Niederman MS, Kollef MH, Shorr AF, Chastre J. Reply to Taccone et al, Wolff and Mourvillier, Masuta and Iwata, and Lahey. Clin Infect Dis 2012. [DOI: 10.1093/cid/cis334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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156
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Fraser JF, Shekar K, Diab S, Dunster K, Foley SR, McDonald CI, Passmore M, Simonova G, Roberts JA, Platts DG, Mullany DV, Fung YL. ECMO - the clinician’s view. ACTA ACUST UNITED AC 2012. [DOI: 10.1111/j.1751-2824.2012.01560.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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157
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Abstract
Critically ill patients admitted to the intensive care unit (ICU) are frequently treated with antimicrobials. The appropriate and judicious use of antimicrobial treatment in the ICU setting is a constant clinical challenge for healthcare staff due to the appearance and spread of new multiresistant pathogens and the need to update knowledge of factors involved in the selection of multiresistance and in the patient's clinical response. In order to optimize the efficacy of empirical antibacterial treatments and to reduce the selection of multiresistant pathogens, different strategies have been advocated, including de-escalation therapy and pre-emptive therapy as well as measurement of pharmacokinetic and pharmacodynamic (pK/pD) parameters for proper dosing adjustment. Although the theoretical arguments of all these strategies are very attractive, evidence of their effectiveness is scarce. The identification of the concentration-dependent and time-dependent activity pattern of antimicrobials allow the classification of drugs into three groups, each group with its own pK/pD characteristics, which are the basis for the identification of new forms of administration of antimicrobials to optimize their efficacy (single dose, loading dose, continuous infusion) and to decrease toxicity. The appearance of new multiresistant pathogens, such as imipenem-resistant Pseudomonas aeruginosa and/or Acinetobacter baumannii, carbapenem-resistant Gram-negative bacteria harbouring carbapenemases, and vancomycin-resistant Enterococcus spp., has determined the use of new antibacterials, the reintroduction of other drugs that have been removed in the past due to toxicity or the use of combinations with in vitro synergy. Finally, pharmacoeconomic aspects should be considered for the choice of appropriate antimicrobials in the care of critically ill patients.
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Affiliation(s)
- Francisco Álvarez-Lerma
- Service of Intensive Care Medicine, Parc de Salut Mar, Universitat Autònoma de Barcelona, Barcelona, Spain.
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158
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Zelenitsky SA, Ariano RE, McCrae ML, Vercaigne LM. Initial Vancomycin Dosing Protocol to Achieve Therapeutic Serum Concentrations in Patients Undergoing Hemodialysis. Clin Infect Dis 2012; 55:527-33. [DOI: 10.1093/cid/cis458] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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159
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Traitement des infections sévères à staphylocoques dorés résistants à la méticilline : vancomycine ou nouvelles molécules ? Données récentes. MEDECINE INTENSIVE REANIMATION 2012. [DOI: 10.1007/s13546-012-0471-z] [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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160
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Determinants of early inadequate vancomycin concentrations during continuous infusion in septic patients. Int J Antimicrob Agents 2012; 39:332-7. [DOI: 10.1016/j.ijantimicag.2011.12.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 12/23/2011] [Accepted: 12/29/2011] [Indexed: 11/22/2022]
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161
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Roberts JA, Norris R, Paterson DL, Martin JH. Therapeutic drug monitoring of antimicrobials. Br J Clin Pharmacol 2012; 73:27-36. [PMID: 21831196 DOI: 10.1111/j.1365-2125.2011.04080.x] [Citation(s) in RCA: 216] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Optimizing the prescription of antimicrobials is required to improve clinical outcome from infections and to reduce the development of antimicrobial resistance. One such method to improve antimicrobial dosing in individual patients is through application of therapeutic drug monitoring (TDM). The aim of this manuscript is to review the place of TDM in the dosing of antimicrobial agents, specifically the importance of pharmacokinetics (PK) and pharmacodynamics (PD) to define the antimicrobial exposures necessary for maximizing killing or inhibition of bacterial growth. In this context, there are robust data for some antimicrobials, including the ratio of a PK parameter (e.g. peak concentration) to the minimal inhibitory concentration of the bacteria associated with maximal antimicrobial effect. Blood sampling of an individual patient can then further define the relevant PK parameter value in that patient and, if necessary, antimicrobial dosing can be adjusted to enable achievement of the target PK/PD ratio. To date, the clinical outcome benefits of a systematic TDM programme for antimicrobials have only been demonstrated for aminoglycosides, although the decreasing susceptibility of bacteria to available antimicrobials and the increasing costs of pharmaceuticals, as well as emerging data on pharmacokinetic variability, suggest that benefits are likely.
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Affiliation(s)
- Jason A Roberts
- Burns, Trauma and Critical Care Research Centre, The University of Queensland, Brisbane, Queensland, Australia.
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162
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Taccone FS, Vincent JL, Denis O, Jacobs F. Should We Abandon Vancomycin for Treatment of Methicillin-Resistant Staphylococcus aureus Pneumonia? Still Questions to Answer. Clin Infect Dis 2012; 55:161-3; author reply 163-5. [DOI: 10.1093/cid/cis332] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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163
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Adnan S, Paterson DL, Lipman J, Kumar S, Li J, Rudd M, Roberts JA. Pharmacokinetics of Beta-Lactam Antibiotics in Patients with Intra-Abdominal Disease: A Structured Review. Surg Infect (Larchmt) 2012; 13:9-17. [DOI: 10.1089/sur.2011.046] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Syamhanin Adnan
- Burns, Trauma and Critical Care Research Centre, The University of Queensland, Brisbane, Australia
- University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia
| | - David L. Paterson
- University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia
- Department of Infectious Diseases, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - Jeffrey Lipman
- Burns, Trauma and Critical Care Research Centre, The University of Queensland, Brisbane, Australia
- Department of Intensive Care, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - Suresh Kumar
- Department of Medicine, Hospital Sungai Buloh, Sungai Buloh, Selangor, Malaysia
| | - Janice Li
- School of Pharmacy, The University of Queensland, Brisbane, Australia
| | - Michael Rudd
- Burns, Trauma and Critical Care Research Centre, The University of Queensland, Brisbane, Australia
- Department of Surgery, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - Jason A. Roberts
- Burns, Trauma and Critical Care Research Centre, The University of Queensland, Brisbane, Australia
- Department of Intensive Care, Royal Brisbane and Women's Hospital, Brisbane, Australia
- Department of Pharmacy, Royal Brisbane and Women's Hospital, Brisbane, Australia
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
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164
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Lipman J, Udy AA, Roberts JA. Do we understand the impact of altered physiology, consequent interventions and resultant clinical scenarios in the intensive care unit? The antibiotic story. Anaesth Intensive Care 2012; 39:999-1000. [PMID: 22165348 DOI: 10.1177/0310057x1103900602] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Early, appropriate antibacterial therapy is a key factor in effectively managing septic critically ill patients1. The prescriber must not only employ an agent of appropriate spectrum, but also in an adequate dose to achieve bacterial eradication at the site of infection. However, the relationship between drug administration and therapeutic success is complex in the critically ill, such that a patient's physiology heavily influences the way drugs distribute into tissue and are eliminated. This represents a significant challenge to the emergency or intensive care physician, and in this manner, personalising therapy, through a greater understanding of how a drug will behave in an individual patient, is likely to lead to improved outcomes.
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165
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Li J, Udy AA, Kirkpatrick CM, Lipman J, Roberts JA. Improving vancomycin prescription in critical illness through a drug use evaluation process: a weight-based dosing intervention study. Int J Antimicrob Agents 2012; 39:69-72. [DOI: 10.1016/j.ijantimicag.2011.08.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 08/26/2011] [Accepted: 08/26/2011] [Indexed: 12/31/2022]
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166
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Vancomycin serum concentration during febrile neutropenia in patients with acute myeloid leukemia. Med Mal Infect 2011; 41:652-6. [DOI: 10.1016/j.medmal.2011.09.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 07/20/2011] [Accepted: 09/23/2011] [Indexed: 11/17/2022]
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167
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Appropriate antibiotic dosage levels in the treatment of severe sepsis and septic shock. Curr Infect Dis Rep 2011; 13:406-15. [PMID: 21805081 DOI: 10.1007/s11908-011-0203-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Antibiotic treatment of critically ill patients remains a significant challenge. Optimal antibacterial strategy should achieve therapeutic drug concentration in the blood as well as the infected site. Achieving therapeutic drug concentrations is particularly difficult when infections are caused by some pathogens, such as Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative rods, because of their low susceptibility to antimicrobials. In sepsis, pharmacokinetics (PKs) of antibiotics are profoundly altered and may result in inadequate drug concentrations, even when recommended regimens are used, which potentially contribute to increased mortality and spread of resistance. The wide inter-individual PK variability observed in septic patients strongly limits the a priori prediction of the optimal dose that should be administered. Higher than standard dosages are necessary for the drugs, such as β-lactams, aminoglycosides, and glycopeptides, that are commonly used as first-line therapy in these patients to maximize their antibacterial activity. However, the benefit of reaching adequate drug concentrations on clinical outcome needs to be further determined.
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