Caspofungin sequestration in a polyacrylonitrile-derived filter: Increasing the dose does not mitigate sequestration

OBJECTIVES

Critically ill patients frequently require continuous renal replacement therapy. Echinocandins are recommended as first-line treatment of candidemia. Preliminary results suggested echinocandin sequestration in a polyacrylonitrile filter. The present study aimed to determine whether increasing the dose might balance sequestration.

METHODS

An STX filter (Baxter-Gambro) was used. A liquid chromatography-mass spectrometry method was used for dosage of caspofungin. In vitro drug disposition was evaluated by NeckEpur (Neckepur, Versailles, France) technology using a crystalloid medium instead of diluted/reconstituted blood, focusing on the disposition of the unbound fraction of drugs. Two concentrations were assessed.

RESULTS

At the low dose, the mean measured initial concentration in the central compartment (CC) was 5.1 ± 0.6 mg/L. One hundred percent of the initial amount was eliminated from the CC within the 6-h session. The mean total clearance from the CC was 9.6 ± 2.5 L/h. The mean percentages of elimination resulting from sequestration and diafiltration were 96.0 ± 5.0 and 4.0 ± 5.2%, respectively. At high dose, the mean measured initial concentration in the CC was 13.1 mg/L. One hundred percent of the initial amount was eliminated from the CC within the 6-h session. The mean total clearance from the CC was 9.5 L/h. The mean percentages of elimination resulting from sequestration and filtration were 88.5% and 11.5%, respectively.

CONCLUSION

Increasing the dose does not mitigate caspofungin sequestration in the STX filter. The results raise caution about the simultaneous use of caspofungin and polyacrylonitrile-derived filters. Intermittent modes of renal replacement therapy might be considered. For sensitive species, fluconazole might be an alternative.

Therapeutic Drug Monitoring of the Echinocandin Antifungal Agents: Is There a Role in Clinical Practice? A Position Statement of the Anti-Infective Drugs Committee of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology

PURPOSE

Reduced exposure to echinocandins has been reported in specific patient populations, such as critically ill patients; however, fixed dosing strategies are still used. The present review examines the accumulated evidence supporting echinocandin therapeutic drug monitoring (TDM) and summarizes available assays and sampling strategies.

METHODS

A literature search was conducted using PubMed in December 2020, with search terms such as echinocandins, anidulafungin, caspofungin, micafungin, or rezafungin with pharmacology, pharmacokinetics (PKs), pharmacodynamics (PDs), drug-drug interactions, TDM, resistance, drug susceptibility testing, toxicity, adverse drug reactions, bioanalysis, chromatography, and mass spectrometry. Data on PD/PD (PK/PD) outcome markers, drug resistance, PK variability, drug-drug interactions, assays, and TDM sampling strategies were summarized.

RESULTS

Echinocandins demonstrate drug exposure-efficacy relationships, and maximum concentration/minimal inhibitory concentration ratio (Cmax/MIC) and area under the concentration-time curve/MIC ratio (AUC/MIC) are proposed PK/PD markers for clinical response. The relationship between drug exposure and toxicity remains poorly clarified. TDM could be valuable in patients at risk of low drug exposure, such as those with critical illness and/or obesity. TDM of echinocandins may also be useful in patients with moderate liver impairment, drug-drug interactions, hypoalbuminemia, and those undergoing extracorporeal membrane oxygenation, as these conditions are associated with altered exposure to caspofungin and/or micafungin. Assays are available to measure anidulafungin, micafungin, and caspofungin concentrations. A limited-sampling strategy for anidulafungin has been reported.

CONCLUSIONS

Echinocandin TDM should be considered in patients at known risk of suboptimal drug exposure. However, for implementing TDM, clinical validation of PK/PD targets is needed.

Pharmacokinetic/pharmacodynamics variability of echinocandins in critically ill patients: A systematic review and meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Anidulafungin, caspofungin and micafungin are three widely used echinocandin drugs licensed for the treatment of invasive fungal infections, and their clinical use is widespread. To evaluate pharmacokinetic/pharmacodynamics variability of echinocandins in critically ill patients by comparing the differences in pharmacokinetic parameters between critically ill patients and healthy volunteers or general patients.

METHODS

MEDLINE, EMBASE, The Cochrane Library and Pubmed were searched from inception until 6 September 2018. Studies investigating the pharmacokinetic parameters of echinocandins in critically ill patients, healthy volunteers or general patients were included. Our primary outcomes included AUC0-24 h , Cmax and Cmin (24 hours). Two reviewers independently reviewed all titles, abstracts and text, and extracted data. We applied R software (R 2017) to conduct meta-analysis.

RESULTS AND DISCUSSION

Of 3235 articles screened, 17 studies were included in the data synthesis. Descriptive data from single-arm studies show that critically ill patients who received caspofungin had more stable AUC0-24 h than those who received anidulafungin and micafungin. The Cmax of critically ill patients who received caspofungin and micafungin was similar to healthy volunteers. However, the Cmax in critically ill patients who received anidulafungin was lower than in healthy volunteers. The Cmin and T1/2 of critically ill patients who received caspofungin were larger than in healthy volunteers. The Vd and CL of critically ill patients receiving anidulafungin and micafungin were larger than in healthy volunteers.

WHAT IS NEW AND CONCLUSION

This systematic review provides an analysis of the pharmacokinetic/pharmacodynamics variability of echinocandins in critically ill patients. Based on the limited data available, caspofungin has less pharmacokinetic/pharmacodynamics variability than anidulafungin and micafungin.

Pharmacokinetic, efficacy, and safety considerations for the use of antifungal drugs in the neonatal population

INTRODUCTION

Invasive fungal infections are an important cause of morbidity and mortality in infants, particularly in extreme prematurity. Successful systemic treatment requires consideration of antifungal efficacy, safety, and pharmacokinetics, including optimization of dosing in this population.

AREAS COVERED

This review summarizes published pharmacokinetic data on four classes of antifungal agents used in the neonatal population. Alterations in absorption, distribution, drug metabolism and clearance in infants compared to adult populations are highlighted. Additionally, pharmacodynamics, safety, and therapeutic drug monitoring are discussed. Recent advancements in neonatal antifungal pharmacotherapies are examined, with emphasis on clinical application.

EXPERT OPINION

Over the last two decades, published studies have provided increased knowledge on pharmacokinetic considerations in the neonatal population. Future research should focus on filling in the knowledge gaps that remain regarding the benefits and risks of combination antifungal therapy, the rising use of micafungin for invasive candidiasis given its fungicidal activity against polyene and azole-resistant Candida species and its minimal adverse effect profile, and the need for pharmacokinetic and safety data of broad spectrum triazoles, like voriconazole and posaconazole, in infants. Furthermore, efforts should focus on well-designed trials, including population pharmacokinetic studies, to develop dosing recommendations with subsequent implementation into clinical practice.

Caspofungin Population Pharmacokinetics in Critically Ill Patients Undergoing Continuous Veno-Venous Haemofiltration or Haemodiafiltration

BACKGROUND AND OBJECTIVE

Sepsis and continuous renal replacement therapy (CRRT) can both significantly affect antifungal pharmacokinetics. This study aimed to describe the pharmacokinetics of caspofungin in critically ill patients during different CRRT modes.

METHODS

Patients receiving caspofungin and undergoing continuous veno-venous haemofiltration (CVVH) or haemodiafiltration (CVVHDF) were eligible to take part in the study. Blood samples were collected at seven sampling times during a dosing interval. Demographics and clinical data were recorded. Population pharmacokinetic analysis and Monte-Carlo simulation were undertaken using Pmetrics.

RESULTS

Twelve pharmacokinetic profiles from nine patients were analysed. The caspofungin CRRT clearance (CL) was 0.048 ± 0.12 L/h for CVVH and 0.042 ± 0.042 L/h for CVVHDF. A two-compartment linear model best described the data. Patient weight was the only covariate affecting drug CL and central volume. The mean (standard deviation) parameter estimates were 0.64 ± 0.12 L/h for CL, 9.35 ± 3.56 L for central volume, 0.25 ± 0.19 per h for the rate constant for drug distribution from central to peripheral compartments and 0.19 ± 0.10 per h from peripheral to central compartments. Based on simulation results, a caspofungin 100 mg loading dose followed by a 50 mg maintenance dose for patients with a total body weight of ≤80 kg best achieved the pharmacokinetic/PD targets whilst a 70 mg maintenance dose was required for patients with a weight of >80 kg.

CONCLUSION

No caspofungin dosing adjustment is necessary for patients undergoing either form of CRRT. However, higher than recommended loading doses of caspofungin are required to achieve pharmacokinetic/pharmacodynamic targets in critically ill patients. Registration: ClinicalTrials.gov Identifier NCT01403220.

Ex vivo Rezafungin Adsorption and Clearance During Continuous Renal Replacement Therapy

BACKGROUND/AIMS

To determine adsorption and transmembrane clearances (CLTM) of rezafungin, a novel long-acting echinocandin, in continuous venovenous hemofiltration (CVVH).

METHODS

A validated ex vivo bovine blood CVVH model using polysulfone and AN69 hemodiafilters was used to evaluate urea and rezafungin CLTM at 3 different ultrafiltrate flow rates. Rezafungin adsorption to the CRRT apparatus was determined for each hemodiafilter.

RESULTS

The sieving coefficient (SC) from CVVH with 3 different ultrafiltrate flow rates was 0 for both HF1400 and Multiflow-150 hemodiafilters, while urea SC was approximately 1 at all flow rates. Hemodiafilter type and ultrafiltrate flow rate did not influence CLTM. Rezafungin adsorption to the CVVH apparatus was not observed for either hemodiafilter.

CONCLUSION

Rezafungin is not removed by CVVH by membrane adsorption or via CLTM. Ultrafiltrate flow rates and hemodiafilter types are unlikely to influence rezafungin CLTM. No dosage adjustment of rezafungin is likely required for critically ill patients receiving CVVH.

Echinocandins for management of invasive candidiasis in patients with liver disease and liver transplantation

Candida species remains one of the most important causes of opportunistic infections worldwide. Invasive candidiasis (IC) is associated with considerable morbidity and mortality in liver disease (LD) patients if not treated promptly. Echinocandins are often recommended as a first-line empirical treatment for managing IC and can especially play a critical role in managing IC in LD patients. However, advanced LD patients are often immunocompromised and critically ill. Hence altered pharmacokinetics, drug interactions as well as tolerance issues of antifungal treatments are a concern in these patients. This comprehensive review examines the epidemiology, risk factors and diagnosis of IC in patients with LD and evaluates differences between three available echinocandins for treating this group of patients.

Filter Adsorption of Anidulafungin to a Polysulfone-Based Hemofilter During CVVHD In Vitro

Candidemia is frequent in critically ill patients, especially in combination with an acute kidney injury (AKI). Echinocandins generally are recommended for therapy of such infections. Recent studies found no need for dosage adjustment in patients with end-stage renal disease receiving hemodialysis, or patients with AKI receiving continuous venovenous hemofiltration. The aim of this in vitro study was to examine the adsorption of anidulafungin to the surface of the hemofilter during continuous venovenous hemodialysis (CVVHD) and its effect on anidulafungin concentrations. The concentration of anidulafungin in the dialyzed fluid, and the dialysate during CVVHD in vitro was examined using three different dialyzed fluids (saline; saline with 40 g/L human albumin; and a mixture of human erythrocytes and fresh frozen plasma). After the end of dialysis, the hemofilter was opened and portions of the filter capillaries were also analyzed to determine the amount of anidulafungin adsorbed. When dialyzing saline, about 99% of the anidulafungin used adsorbed to the hemofilter capillaries; in the experiments with saline with 40 g/L albumin, about 60% adsorbed to the hemofilter's surface, and when blood was dialyzed, 35% was found adsorbed after analyzing the filter capillaries. Anidulafungin was not detectable in the dialysate of any of the experiments, consequently the dialysis clearance was 0 mL/min. In conclusion, during CVVHD in vitro we found remarkable adsorption of anidulafungin to the hemofilter's surface, yet the effect on the tissue concentration needs further examination.

Micafungin Plasma Levels Are Not Affected by Continuous Renal Replacement Therapy: Experience in Critically Ill Patients

Critically ill patients often experience acute kidney injury and the need for renal replacement therapy in the course of their treatment in an intensive care unit (ICU). These patients are at an increased risk for candidiasis. Although there have been several reports of micafungin disposition during renal replacement therapy, to this date there are no data describing the elimination of micafungin during high-dose continuous venovenous hemodiafiltration with modified AN69 membranes. The aim of this prospective open-label pharmacokinetic study was to assess whether micafungin plasma levels are affected by continuous hemodiafiltration in critical ill patients using the commonly employed AN69 membrane. A total of 10 critically ill patients with micafungin treatment due to suspected or proven candidemia were included in this trial. Prefilter/postfilter micafungin clearance was measured to be 46.0 ml/min (±21.7 ml/min; n = 75 individual time points), while hemofilter clearance calculated by the sieving coefficient was 0.0038 ml/min (±0.002 ml/min; n = 75 individual time points). Total body clearance was measured to be 14.0 ml/min (±7.0 ml/min; n = 12). The population area under the curve from 0 to 24 h (AUC_0-24) was calculated as 158.5 mg · h/liter (±79.5 mg · h/liter; n = 13). In spite of high protein binding, no dose modification is necessary in patients receiving continuous venovenous hemodiafiltration with AN69 membranes. A dose elevation may, however, be justified in certain cases. (This study has been registered at ClinicalTrials.gov under identifier NCT02651038.).

Pharmacokinetics of antifungal drugs: practical implications for optimized treatment of patients

Introduction

Because of the high mortality of invasive fungal infections (IFIs), appropriate exposure to antifungals appears to be crucial for therapeutic efficacy and safety.

Materials and methods

This review summarises published pharmacokinetic data on systemically administered antifungals focusing on co-morbidities, target-site penetration, and combination antifungal therapy.

Conclusions and discussion

Amphotericin B is eliminated unchanged via urine and faeces. Flucytosine and fluconazole display low protein binding and are eliminated by the kidney. Itraconazole, voriconazole, posaconazole and isavuconazole are metabolised in the liver. Azoles are substrates and inhibitors of cytochrome P450 (CYP) isoenzymes and are therefore involved in numerous drug–drug interactions. Anidulafungin is spontaneously degraded in the plasma. Caspofungin and micafungin undergo enzymatic metabolism in the liver, which is independent of CYP. Although several drug–drug interactions occur during caspofungin and micafungin treatment, echinocandins display a lower potential for drug–drug interactions. Flucytosine and azoles penetrate into most of relevant tissues. Amphotericin B accumulates in the liver and in the spleen. Its concentrations in lung and kidney are intermediate and relatively low myocardium and brain. Tissue distribution of echinocandins is similar to that of amphotericin. Combination antifungal therapy is established for cryptococcosis but controversial in other IFIs such as invasive aspergillosis and mucormycosis.

Dosing of caspofungin based on a pharmacokinetic/pharmacodynamic index for the treatment of invasive fungal infections in critically ill patients on continuous venovenous haemodiafiltration

INTRODUCTION

The study objective was to evaluate the efficacy of different dosages of caspofungin in the treatment of invasive candidiasis and aspergillosis, in relation to the probability of pharmacokinetic/pharmacodynamic (PK/PD) target attainment, using modelling and Monte Carlo simulations in critically ill adult patients on continuous haemodiafiltration.

METHODS

Critically ill adult patients on continuous venovenous haemodiafiltration treated with caspofungin were analysed. A population PK model was developed. Four caspofungin dosing regimens were simulated: the licensed regimen, 70 mg/day, 100 mg/day or 200 mg/day. A PK/PD target was defined as the ratio between the area under the caspofungin concentration-time curve over 24 hours and the minimal inhibitory concentration (AUC/MIC) for candidiasis or the minimal effective concentrations (AUC/MEC) for Aspergillus spp. Target attainment based on preclinical target for Candida and Aspergillus was assessed for different MIC or MEC, respectively.

RESULTS

Concentration-time data were described by a two-compartment model. Body-weight and protein concentration were the only covariates identified by the model. Goodness-of-fit plots and bootstrap analysis proved the model had a satisfactory performance. As expected, a higher maintenance dose resulted in a higher exposure. Target attainment was >90% for candidiasis (MIC≤0.06 mg/L) and aspergillosis (MEC≤0.5 mg/L), irrespective of the dosing regimen, but not for C. parapsilosis. Standard regimen was insufficient to reach the target for C. albicans and C. parapsilosis with MIC≥0.1 mg/L.

CONCLUSION

The licensed regimen of caspofungin is insufficient to achieve the PK/PD targets in critically ill patients on haemodiafiltration. The determination of MICs will enable dose scheme selection.

Antifungal pharmacodynamics: Latin America's perspective

The current increment of invasive fungal infections and the availability of new broad-spectrum antifungal agents has increased the use of these agents by non-expert practitioners, without an impact on mortality. To improve efficacy while minimizing prescription errors and to reduce the high monetary cost to the health systems, the principles of pharmacokinetics (PK) and pharmacodynamics (PD) are necessary. A systematic review of the PD of antifungals agents was performed aiming at the practicing physician without expertise in this field. The initial section of this review focuses on the general concepts of antimicrobial PD. In vitro studies, fungal susceptibility and antifungal serum concentrations are related with different doses and dosing schedules, determining the PD indices and the magnitude required to obtain a specific outcome. Herein the PD of the most used antifungal drug classes in Latin America (polyenes, azoles, and echinocandins) is discussed.

[Echinocandins: Applied pharmacology]

The echinocandins share pharmacodynamic properties, although there are some interesting differences in their pharmacokinetic behaviour in the clinical practice. They are not absorbed by the oral route. They have a somewhat special distribution in the organism, as some of them can reach high intracellular concentrations while, with some others, the concentration is reduced. They are highly bound to plasma proteins, thus it is recommended to administer a loading dose for anidulafungin and caspofungin, although this procedure is not yet clear with micafungin. Echinocandins are excreted via a non-microsomal metabolism, so the urinary concentration is very low. Some carrier proteins that take part in the biliary clearance process are probably involved in the interactions described with caspofungin and micafungin. These two drugs must be used with caution in patients with severely impaired hepatic function, while all of them can be used without special precautions when there is renal impairment or the patient requires renal replacement therapy.

Pharmacokinetic/pharmacodynamic adequacy of echinocandins against Candida spp. in intensive care unit patients and general patient populations

This study evaluated whether contemporary echinocandin regimens achieved pharmacokinetic/pharmacodynamic targets in ICU patients and general patient populations (GPPs) and assessed caspofungin (CAS) regimens in hepatic impairment (HI) patients. A Monte Carlo simulation was performed using previously published data. Recommended dosing regimens of echinocandins in ICU patients, GPPs and healthy volunteers were evaluated: 70mg loading dose then 50mg maintenance dose (70/50mg) for CAS; 100mg q24h for micafungin (MCF); and 200/100mg for anidulafungin (ANF). Moreover, CAS 70mg and 100mg q24h in GPPs, and CAS 70/50mg and 70/35mg in mild and moderate HI patients, respectively, were evaluated. Cumulative fraction of response (CFR) was calculated for each dosing regimen. For Candida albicans, CFRs for the recommended doses of CAS, MCF and ANF were 95.8%, 13.5% and 50.5% in ICU patients and 96.3%, 42.4% and 61.6% in GPPs, respectively; for Candida glabrata, CFRs were 99.4%, 90.6% and 44.6% in ICU patients and 99.5%, 97.1% and 59.8% in GPPs. For Candida parapsilosis, CFRs of echinocandins for standard regimens were <70%; only CAS 100mg q24h achieved the target CFR. CAS 70/50mg and 70/35mg in mild and moderate HI patients were appropriate. Considerable interindividual variability was observed. For C. albicans and C. glabrata, CAS is good choice both for ICU and other patient populations, but for C. parapsilosis an increased dose should be considered. For MCF and ANF, administering higher doses with longer dosing intervals achieves better target attainment and should be investigated in clinical trials.

Impact of special patient populations on the pharmacokinetics of echinocandins

Echinocandins belong to the class of antifungal agents. Currently, three echinocandin drugs are licensed for intravenous treatment of invasive fungal infections: anidulafungin, caspofungin and micafungin. While their antifungal activity overlaps, there are substantial differences in pharmacokinetics (PK). Numerous factors may account for variability in PK of echinocandins including age (pediatrics vs adults), body surface area and body composition (normal weight vs obesity), disease status (e.g., critically ill and burn patients) and organ dysfunction (kidney and liver impairment). Subsequent effects of altered exposure might impact efficacy and safety. Knowledge of PK behavior is crucial in optimal clinical utilization of echinocandin in a specific patient or patient population. This review provides up-to-date information on PK data of anidulafungin, caspofungin and micafungin in special patient populations. Patient populations addressed are neonates, children and adolescents, obese patients, patients with hepatic or renal impairment, critically ill patients (including burn patients) and patients with hematological diseases.

[Patients treated with micafungin during their stay in intensive care unit]

OBJECTIVES

To determine the reasons of prescription, the characteristics of patients and factors that affected the outcome of critically ill patients treated with micafungin (MCF) during their stay in Spanish ICUs.

MATERIAL AND METHODS

Observational, retrospective and multicenter study. Patients admitted to the ICU between March 2011 and October 2012 (20-month period) treated with MCF for any reason were included in the study. Severity of patients at the beginning of treatment was measured with the APACHE II, SOFA, Child-Pugh and MELD scores. Reasons for the use of MCF were classified as prophylaxis, preemptive treatment, empirical treatment and directed treatment. Continuous variables are expressed as mean and standard deviation or median, and categorical variables as percentages. A multivariate analysis was performed to identify variables related to intra-ICU mortality.

RESULTS

The study population included 139 patients admitted to 19 Spanish ICUs, with a mean age of 57.3 (17.1) years, 89 (64%) men, with surgical (53.2%) and/or medical (44.6%) conditions, APACHE II score of 20.6 (7.7) and SOFA score of 8.4 (4.3), with 84.2% of patients requiring mechanical ventilation, 59% parenteral nutrition, 37.4% extrarenal depuration procedures and 37.4% treatment with steroids. MCF was indicated as empirical treatment of a proven infection in 51 (36.7%) cases, pre-emptive treatment in 50 (36%) especially as a result of the application of the Candida score (32 cases), directed treatment of fungal infection in 23 (16.5%) and as prophylactic treatment in 15 (10.8%) cases. In 108 (77%) cases, a daily dose of 100mg was administered, with a loading dose in only 9 cases (6.5%). The mean duration of treatment was 13.1 (13) days. A total of 59 (42.4%) patients died during their stay in the ICU and 16 after ICU discharge (hospital mortality 53.9%). Independent risk factors for intra-ICU mortality were the Child-Pugh score (OR 1.45, 95% CI 1.162-1.813; P=.001) and the MELD score (OR 1.05, 95% CI 1.011-1.099; P=.014).

CONCLUSIONS

MCF is usually administered at a dose of 100mg/day, without loading dose and in 72.7% of cases as pre-emptive or empirical treatment. Factors that better predicted mortality were indicators of liver insufficiency at the time of starting treatment.

How to manage aspergillosis in non-neutropenic intensive care unit patients

Invasive aspergillosis has been mainly reported among immunocompromised patients during prolonged periods of neutropenia. Recently, however, non-neutropenic patients in the ICU population have shown an increasing risk profile for aspergillosis. Associations with chronic obstructive pulmonary disease and corticosteroid therapy have been frequently documented in this cohort. Difficulties in achieving a timely diagnosis of aspergillosis in non-neutropenic patients is related to the non-specificity of symptoms and to lower yields with microbiological tests compared to neutropenic patients. Since high mortality rates are typical of invasive aspergillosis in critically ill patients, a high level of suspicion and prompt initiation of adequate antifungal treatment are mandatory. Epidemiology, risk factors, diagnostic algorithms, and different approaches in antifungal therapy for invasive aspergillosis in non-neutropenic patients are reviewed.

EPICO 2.0 project. Development of educational therapeutic recommendations using the DELPHI technique on invasive candidiasis in critically ill adult patients in special situations

BACKGROUND

Although there has been an improved management of invasive candidiasis in the last decade, still controversial issues remain, especially in different therapeutic critical care scenarios.

AIMS

We sought to identify the core clinical knowledge and to achieve high agreement recommendations required to care for critically ill adult patients with invasive candidiasis for antifungal treatment in special situations and different scenarios.

METHODS

Second prospective Spanish survey reaching consensus by the DELPHI technique, conducted anonymously by electronic e-mail in the first phase to 23 national multidisciplinary experts in invasive fungal infections from five national scientific societies including intensivists, anesthesiologists, microbiologists, pharmacologists and infectious disease specialists, answering 30 questions prepared by a coordination group after a strict review of literature in the last five years. The educational objectives spanned four categories, including peritoneal candidiasis, immunocompromised patients, special situations, and organ failures. The agreement among panelists in each item should be higher than 75% to be selected. In a second phase, after extracting recommendations from the selected items, a meeting was held with more than 60 specialists in a second round invited to validate the preselected recommendations.

MEASUREMENTS AND MAIN RESULTS

In the first phase, 15 recommendations were preselected (peritoneal candidiasis (3), immunocompromised patients (6), special situations (3), and organ failures (3)). After the second round the following 13 were validated: Peritoneal candidiasis (3): Source control and early adequate antifungal treatment is mandatory; empirical antifungal treatment is recommended in secondary nosocomial peritonitis with Candida spp. colonization risk factors and in tertiary peritonitis. Immunocompromised patients (5): consider hepatotoxicity and interactions before starting antifungal treatment with azoles in transplanted patients; treat candidemia in neutropenic adult patients with antifungal drugs at least 14 days after the first blood culture negative and until normalization of neutrophils is achieved. Caspofungin, if needed, is the echinocandin with most scientific evidence to treat candidemia in neutropenic adult patients; caspofungin is also the first choice drug to treat febrile candidemia; in neutropenic patients with candidemia remove catheter. Special situations (2): in moderate hepatocellular failure, patients with invasive candidiasis use echinocandins (preferably low doses of anidulafungin and caspofungin) and try to avoid azoles; in case of possible interactions review all the drugs involved and preferably use anidulafungin. Organ failures (3): echinocandins are the safest antifungal drugs; reconsider the use of azoles in patients under renal replacement therapy; all of the echinocandins to treat patients under continuous renal replacement therapy are accepted and do not require dosage adjustment.

CONCLUSIONS

Treatment of invasive candidiasis in ICU patients requires a broad range of knowledge and skills as summarized in our recommendations. These recommendations may help to optimize the therapeutic management of these patients in special situations and different scenarios and improve their outcome based on the DELPHI methodology.

Treatment with echinocandins during continuous renal replacement therapy

Echinocandins are indicated as first-line treatment for invasive candidiasis in moderate to severe illness. As sepsis is the main cause of acute kidney injury, the combination of echinocandin treatment and continuous renal replacement therapy (CRRT) is common. Optimizing antibiotic dosage in critically ill patients receiving CRRT is challenging. The pharmacokinetics of echinocandins have been studied under various clinical conditions; however, data for CRRT patients are scarce. Classically, drugs like echinocandins with high protein binding and predominantly non-renal elimination are not removed by CRRT, indicating that no dosage adjustment is required. However, recent studies report different proportions of echinocandins lost by filter adsorption. Nevertheless, the clinical significance of these findings remains unclear.

[Pharmacokinetic and pharmacodynamic aspects in antibiotic treatment]

Severe sepsis and septic shock have a high mortality and, therefore require fast and effective antibiotic treatment with low toxicity. Because of sepsis-induced pathophysiological changes, pharmacokinetics of antimicrobial agents can be altered. Particularly water-soluble drugs display an enhanced volume of distribution during early sepsis. Therefore high loading doses are necessary. Renal clearance can also be increased at this time. Later on, organ damage frequently occurs resulting in delayed drug elimination which requires further dose adjustment. The different classes of antibiotics differ in their relevant pharmacokinetic-pharmacodynamic target parameters. Thus, the efficacy of an antimicrobial agent can depend on its concentration, on the exposure time, and on the total exposure as expressed by the area under the time-concentration curve. During treatment with time-dependent antibiotics (e.g. β-lactams), their concentration should be maintained above the minimal inhibitory concentration (MIC) warranting more frequent administration or continuous infusion. For concentration dependent agents (e.g. aminoglycosides), the single dose is pivotal, whereas the dosage interval can be extended. Drug-drug interactions involving antibiotics are mainly caused by inhibition of their metabolism, particularly of cytochrome P 450 iso-enzymes, or by additive toxic effects. They can result in severe complications such as renal failure or ventricular arrhythmias. Conversely, enzyme induction may lead to subtherapeutic drug levels. When continuous renal replacement therapy is required, the dosage of antibiotics has to be adapted according to the results of respective pharmacokinetic studies.

Pharmacokinetics of anidulafungin in two critically ill patients with septic shock undergoing CVVH

Candidemia is associated with high mortality rate especially in critically ill (ICU) patients with septic shock and echinocandins such as anidulafungin are recommended as first-line treatment. Available pharmacokinetic studies of anidulafungin in healthy volunteers and in patients with renal or hepatic impairment showed that no dose adjustment is needed even in patients receiving standard intermittent haemodialysis. However, few data are available with continuous veno-venous haemofiltration (CVVH). In this study, the pharmacokinetic of anidulafungin was studied in two ICU patients with candidemia and septic shock undergoing CVVH. Both patients had satisfactory parameters of C(max) (9.04 and 5.68 mg/l, respectively), area under the curve (AUC) (95.18 and 67.48 mg/l h) and C(min) (2.61 and 1.43 mg/l). AUC/MIC ratio and C(max)/MIC values were: 11887 and 8435; 1130.25 and 710, for patients 1 and 2, respectively. Our data confirm that in patients with septic shock anidulafungin presents only mild pharmacokinetic changes compared to data reported during CVVH alone.

Pharmacokinetics of caspofungin in critically ill patients on continuous renal replacement therapy

Caspofungin pharmacokinetics was assessed in 27 critically ill patients, including 7 on continuous venovenous hemofiltration (CVVH), 8 on continuous venovenous hemodialysis (CVVHD), and 13 not requiring continuous renal replacement therapy (CRRT). Caspofungin exposure during CRRT was very similar to that of the control group and comparable to that in healthy volunteers. Caspofungin clearance by CRRT was very low. Therefore, the standard dosage of caspofungin is probably adequate for critically ill patients undergoing CVVH or CVVHD.

[Candida peritonitis in a haemodynamically stable patient. First choice of antifungal treatment … fluconazole?]

BACKGROUND

Candida peritonitis in postoperative patients is an independent predictor of mortality. Empirical early antifungal therapy should be started in these patients, since according to the results of studies in patients with candidemia, this has an impact on the prognosis. The treatment recommended by clinical practice guidelines in patients with haemodynamic instability are candins, but they do not make explicit recommendations for patients with dysfunction of other organs, or high lactate levels.

CASE REPORT

A case of rescue treatment with anidulafungin in a patient with candidemia and Candida glabrata peritonitis postoperative haemodynamically stable, but with an acute renal failure and elevated plasma lactate, is reported. We discuss the antifungal treatment recommendations established by clinical practice guidelines.

CONCLUSIONS

One conclusion based on this case is that the haemodynamic instability as a marker of severe sepsis must be equated with dysfunction of any organ and/or a plasma lactate level ≥ 2.5 mmol/l in order to advocate candins as an antifungal treatment. In addition, it should be emphasised that anidulafungin was effective in a clinically difficult patient with candidemia and Candida peritonitis, even when used as late rescue antifungal treatment.

The use of antifungal therapy in neonatal intensive care

Invasive fungal infections remain a significant cause of infection-related mortality and morbidity in preterm infants. Central nervous system involvement is the hallmark of neonatal candidiasis, differentiating the disease's impact on young infants from that among all other patient populations. Over the past decade, the number of antifungal agents in development has grown, but most are not labeled for use in newborns. We summarize the findings of several antifungal studies that have been completed to date, emphasizing those including infant populations. We conclude that more studies are required for antifungals to be used safely and effectively in infants.

Multiple-dose pharmacokinetics of daptomycin during continuous venovenous haemodiafiltration

OBJECTIVES

Daptomycin is bactericidal against Gram-positive bacteria, with peak-dependent effect but trough-dependent toxicity. This study was performed to develop dosing recommendations in continuous venovenous haemodiafiltration (CVVHDF).

PATIENTS AND METHODS

Nine critically ill patients in intensive care units of the Medical University Hospital of Vienna, requiring CVVHDF due to acute renal failure and antimicrobial treatment, were included. Blood and effluent samples were collected over 72 h to determine daptomycin concentrations by HPLC. Pharmacokinetic parameters were based on 10 sampling timepoints during the first 24 h, and peak and trough samples thereafter. An open two-compartment model was fitted to each subject's plasma concentration-time data. Simulations of serum concentration-time profiles after different doses and intervals were performed using ADAPT 5.

RESULTS

Peak plasma concentrations with 6 mg/kg daptomycin were 62.2 ± 16.2, 66.1 ± 17.3 and 78.5 ± 22.1 mg/L on days 1, 2 and 3, respectively. The total clearance was 6.1 ± 4.9 mL/min, and the elimination half-life was 17.8 ± 9.7 h. Daptomycin was filtrated and could therefore be measured in the effluent. Protein binding was lower than that seen in healthy volunteers. The unbound fraction was 16 ± 4.5%. All subjects maintained trough serum concentrations above 4 mg/L, at which relevant pathogens are considered daptomycin-susceptible. Accumulation resulted when daptomycin was given every 24 h. Simulation of 8 mg/kg daptomycin given every 48 h resulted in adequate levels without accumulation.

CONCLUSIONS

We recommend 8 mg/kg daptomycin every 48 h in patients on CVVHDF and therapeutic drug monitoring, if possible.

Using pharmacokinetics and pharmacodynamics to optimise dosing of antifungal agents in critically ill patients: a systematic review

The prevalence of invasive fungal infections (IFIs) caused by Candida spp. is increasing in critically ill patients. Recent development of new antifungal agents has significantly contributed to the successful treatment of IFIs. However, the pharmacokinetics of antifungal agents can be altered in a number of disease states, including critical illness. Therefore, doses established in healthy volunteers and other patient groups may not be appropriate for the critically ill. Moreover, inadequate dosing may contribute to treatment failure and the emergence of resistance. This systematic review provides a critical analysis of the pharmacokinetics of antifungal agents in the critically ill and their relevance to dosing requirements in clinical practice. Based on the limited data available, dosing of some antifungal agents may have to be adjusted in critically ill patients with conserved renal function as well as in those requiring renal replacement therapy. Further research to confirm the appropriateness of current dosing strategies to attain the appropriate pharmacodynamic targets is recommended.