Influence of continuous venovenous hemofiltration and continuous venovenous hemodiafiltration on the disposition of doripenem

Correlation of antimicrobial fraction unbound and sieving coefficient in critically ill patients on continuous renal replacement therapy: a systematic review

Background

Fraction unbound has been used as a surrogate for antimicrobial sieving coefficient (SC) to predict extracorporeal clearance in critically ill patients on continuous renal replacement therapy (CRRT), but this is based largely on expert opinion.

Objectives

To examine relationships between package insert-derived fraction unbound (Fu-P), study-specific fraction unbound (Fu-S), and SC in critically ill patients receiving CRRT.

Methods

English-language studies containing patient-specific in vivo pharmacokinetic parameters for antimicrobials in critically ill patients requiring CRRT were included. The primary outcome included correlations between Fu-S, Fu-P, and SC. Secondary outcomes included correlations across protein binding quartiles, serum albumin, and predicted in-hospital mortality, and identification of predictors for SC through multivariable analysis.

Results

Eighty-nine studies including 32 antimicrobials were included for analysis. SC was moderately correlated to Fu-S (R2 = 0.55, P < 0.001) and Fu-P (R2 = 0.41, P < 0.001). SC was best correlated to Fu-S in first (<69%) and fourth (>92%) quartiles of fraction unbound and above median albumin concentrations of 24.5 g/L (R2 = 0.71, P = 0.07). Conversely, correlation was weaker in patients with mortality estimates greater than the median of 55% (R2 = 0.06, P = 0.84). SC and Fu-P were also best correlated in the first quartile of antimicrobial fraction unbound (R2 = 0.66, P < 0.001). Increasing Fu-P, flow rate, membrane surface area, and serum albumin, and decreasing physiologic charge significantly predicted increasing SC.

Conclusions

Fu-S and Fu-P were both reasonably correlated to SC. Caution should be taken when using Fu-S to calculate extracorporeal clearance in antimicrobials with 69%–92% fraction unbound or with >55% estimated in-hospital patient mortality. Fu-P may serve as a rudimentary surrogate for SC when Fu-S is unavailable.

In vivo evaluation of drug dialyzability in a rat model of hemodialysis

It is important to calculate the drug removal by hemodialysis (HD) for drug dosing regimens in HD patients. However, there are limited and inconsistent information about the dialyzability of drugs by HD. Therefore, the aim of our study is to evaluate drug removal by utilizing a rat model of HD (HD rat) and to extrapolate this result to the drug removal rate in HD patients. HD rats received bilateral nephrectomy and HD for 2 h. The dialysis removal of 6 drugs was evaluated in HD rats. Dialysis efficiency, plasma protein binding rate (PBR) and distribution volume (Vd) of drugs were also measured. Furthermore, we examined the correlation between the dialyzability of drug in HD rats and humans and constructed the prediction formula of the drug dialyzability in HD patients. The clearance of urea and creatinine and normalized dialysis dose in HD rats were 0.83 ± 0.07 mL/min, 0.70 ± 0.08 mL/min, and 0.13 ± 0.06, respectively. The drug dialyzability in HD rats was similar to reported clinical data except for doripenem. A higher correlation was observed between drug dialyzability in reported clinical data and HD rats which were adjusted for PBR (r² = 0.936; p < 0.001) compared to unadjusted (r² = 0.812; p = 0.009). Therefore, we constructed the prediction formula of the drug dialyzability in HD patients by utilizing the HD rat model and PBR. This study is useful for evaluating the dialyzability of high-risk drugs in a clinical setting and might provide appropriate preclinical dialyzability data for new drug.

Pharmacokinetics and Pharmacodynamics of Anti-infective Agents during Continuous Veno-venous Hemofiltration in Critically Ill Patients: Lessons Learned from an Ancillary Study of the IVOIRE Trial

Background

Hemofiltration rate, changes in blood and ultrafiltration flow, and discrepancies between the prescribed and administered doses strongly influence pharmacokinetics (PK) and pharmacodynamics (PD) of antimicrobial agents during continuous veno-venous hemofiltration (CVVH) in critically ill patients.

Methods

Ancillary data were from the prospective multicenter IVOIRE (hIgh VOlume in Intensive caRE) study. High volume (HV, 70 mL/kg/h) was at random compared with standard volume (SV, 35 mL/kg/h) CVVH in septic shock patients with acute kidney injury (AKI). PK/PD parameters for all antimicrobial agents used in each patient were studied during five days.

Results

Antimicrobial treatment met efficacy targets for both percentage of time above the minimal inhibitory concentration and inhibitory quotient. A significant correlation was observed between the ultrafiltration flow and total systemic clearance (Spearman test: P < 0.005) and between CVVH clearance and drug elimination half-life (Spearman test: P < 0.005). All agents were easily filtered. Mean sieving coefficient ranged from 38.7% to 96.7%. Mean elimination half-life of all agents was significantly shorter during HV-CVVH (from 1.29 to 28.54 h) than during SV-CVVH (from 1.51 to 33.85 h) (P < 0.05).

Conclusions

This study confirms that CVVH influences the PK/PD behavior of most antimicrobial agents. Antimicrobial elimination was directly correlated with convection rate. Current antimicrobial dose recommendations will expose patients to underdosing and increase the risk for treatment failure and development of resistance. Dose recommendations are proposed for some major antibiotic and antifungal treatments in patients receiving at least 25 mL/kg/h CVVH.

Continuous high-dose infusion of doripenem in a pneumonia patient infected by carbapenem-resistant Pseudomonas aeruginosa: a case report

Background

Despite the high mortality of patients with sepsis and carbapenem-resistant bacteria infection, appropriate antimicrobial therapies are yet to be established. Here, we have reported the case of a patient with pneumonia that subsequently developed by carbapenem-resistant Pseudomonas aeruginosa infection and was treated with a continuous high-dose infusion of doripenem.

Case presentation

We started a continuous intravenous infusion of doripenem 3 g/day although the 59-year-old woman (body weight, 45 kg) had developed septic acute kidney injury, followed by continuous renal replacement therapy (the effluent flow rate was 650 mL/h). The minimum inhibitory concentration (MIC) of doripenem was 8 mg/L. The concentration of unbound doripenem in the serum was measured by using high-performance liquid chromatography. Twenty hours after the initial dose, the patient’s serum level of doripenem was 47.8 μg/mL; the level decreased to 33.6 μg/mL at 111 h after initial dosing. The unbound doripenem concentration in the serum was maintained four times above the MIC throughout the treatment. After the completion of 11 days of dosing, the patient was discharged from the intensive care unit. During the treatment period, the MIC remained at 8 mg/L.

Conclusions

A continuous high-dose infusion of doripenem is a potentially efficient strategy for the treatment of antimicrobial-resistant bacteria. Moreover, therapeutic drug monitoring may be useful for patients displaying variable pharmacokinetics, because the MIC is generally high in resistant bacteria.

Pharmacokinetics of cefoperazone/sulbactam in critically ill patients receiving continuous venovenous hemofiltration

PURPOSE

Cefoperazone/sulbactam (CFP/SUL) is a β-lactam/β-lactamase inhibitor combination with little data available for the development of effective dosing guidelines during continuous renal replacement therapy. This study aimed to investigate the pharmacokinetics (PK) of cefoperazone/sulbactam in critically ill patients on continuous venovenous hemofiltration (CVVH).

METHODS

A prospective, single-center, and open-label study was conducted. Critically ill patients receiving CVVH with 3 g cefoperazone/sulbactam (2.0/1.0 g) intravenously every 8 h were recruited. Serial blood and ultrafiltrate samples were paired collected for initial dose (occasion 1) and steady state (occasion 2). PK was assessed by non-compartmental analysis, and pharmacodynamics (PD) was evaluated by the percent of time for which drug concentrations exceed the minimum inhibitory concentration (%T >MIC).

RESULTS

Total fourteen patients were enrolled. Volume of distribution at steady state (V ss) of cefoperazone and sulbactam for initial doses (20.8 ± and 28.4 L, respectively) increased significantly compared with those in healthy volunteers (P = 0.009 for CFP, P = 0.030 for SUL). Both cefoperazone and sulbactam showed significantly lower total clearance (CLt) (46.2 and 117.6 mL/min, respectively) compared with healthy volunteers (P = 0.000 for CFP, P = 0.017 for SUL). There is no significant difference in PK between occasion 1 and occasion 2 (P > 0.05). For occasion 1, mean CVVH clearance accounted for 34.3 and 33.9 % for CLt of cefoperazone and sulbactam, respectively. The minimum PD target of 60%T >MIC was achieved in seven of eight patients. For occasion 2, eight of nine patients achieved cefoperazone concentrations that were above the MIC for the entire dosing interval.

CONCLUSIONS

PK of cefoperazone/sulbactam was altered in critically ill patients undergoing CVVH. Therapeutic drug monitoring would be recommended to individualize the dose regimen.

Doripenem Treatment during Continuous Renal Replacement Therapy

Doripenem is a broad-spectrum parenteral carbapenem with enhanced activity against Pseudomonas aeruginosa. While the initial dosing recommendation for renally competent patients and patients undergoing continuous renal replacement therapy (cRRT) was 500 mg every 8 h (q8h), the dose for renally competent patients was updated to 1 g q8h in June 2012. There are no updated data for the dosing of patients on continuous renal replacement therapy. The original dosing regimen for cRRT patients was based on nonseptic patients, while newer publications chose comparatively low target concentrations for a carbapenem. Thus, there is an urgent need for updated recommendations for dosing during cRRT. In the trial presented here, we included 13 oliguric septic patients undergoing cRRT in an intensive care setting. Five patients each were treated with hemodiafiltration or hemodialysis, while three patients received hemofiltration treatment. All patients received 1 g doripenem every 8 h. Doripenem concentrations in the plasma and ultrafiltrate were measured over 48 h. The mean hemofilter clearance was 36.53 ml/min, and the mean volume of distribution was 59.26 liters. The steady-state trough levels were found at 8.5 mg/liter, with no considerable accumulation. Based on pharmacokinetic and pharmacodynamic considerations, we propose a regimen of 1 g q8h, which may be combined with a loading dose of 1.5 to 2 g for critically ill patients. (This study has been registered with EudraCT under registration no. 2009-018010-18 and at ClinicalTrials.gov under registration no. NCT02018939.).

Haemodiafiltration, haemofiltration and haemodialysis for end-stage kidney disease

BACKGROUND

Convective dialysis modalities (haemofiltration (HF), haemodiafiltration (HDF), and acetate-free biofiltration (AFB)) removed excess body fluid across the dialysis membrane with positive pressure and accumulated middle- and larger-size accumulated solutes more efficiently than haemodialysis (HD). This increased larger solute removal combined with use of ultra-pure dialysis fluid in convective dialysis is hypothesised to reduce the frequency and severity of symptoms during dialysis as well as improve clinical outcomes. Convective dialysis therapies (HDF and HF) are associated with lower mortality compared to diffusive therapy (HD) in observational studies. This is an update of a review first published in 2006.

OBJECTIVES

To compare convective (HF, HDF, or AFB) with diffusive (HD) dialysis modalities on clinical outcomes (mortality, major cardiovascular events, hospitalisation and treatment-related adverse events) in men and women with end-stage kidney disease (ESKD).

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register (to 18 February 2015) through contact with a Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials comparing convective therapy (HF, HDF, AFB) with another convective therapy or diffusive therapy (HD) for treatment of ESKD.

DATA COLLECTION AND ANALYSIS

Two independent authors identified studies, extracted data and assessed study risk of bias. We summarised treatment effects using the random effects model. We reported results as a risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous data together with 95% confidence intervals (CI). We assessed for heterogeneity using the Chi(2) test and explored the amount of variation in treatment estimates beyond that expected by chance using the I(2) statistic.

MAIN RESULTS

Twenty studies comprising 667 participants were included in the 2006 review. In that review, there was insufficient evidence of treatment effects on major clinical outcomes to draw clinically meaningful conclusions. Searching to February 2015 identified 40 eligible studies comprising 3483 participants overall. In total, 35 studies (4039 participants) compared HF, HDF or AFB with HD, three studies (54 participants) compared AFB with HDF, and three studies (129 participants) compared HDF with HF.Risks of bias in all studies were generally high resulting in low confidence in estimated treatment effects. Convective dialysis had no significant effect on all-cause mortality (11 studies, 3396 participants: RR 0.87, 95% CI 0.72 to 1.05; I(2) = 34%), but significantly reduced cardiovascular mortality (6 studies, 2889 participants: RR 0.75, 95% CI 0.61 to 0.92; I(2) = 0%). One study reported no significant effect on rates of nonfatal cardiovascular events (714 participants: RR 1.14, 95% CI 0.86 to 1.50) and two studies showed no significant difference in hospitalisation (2 studies, 1688 participants: RR 1.23, 95% CI 0.93 to 1.63; I(2) = 0%). One study reported rates of hypotension during dialysis were significantly reduced with convective therapy (906 participants: RR 0.72, 95% CI 0.66 to 0.80). Adverse events were not systematically evaluated in most studies and data for health-related quality of life were sparse. Convective therapies significantly reduced predialysis levels of B2 microglobulin (12 studies, 1813 participants: MD -5.55 mg/dL, 95% CI -9.11 to -1.98; I(2) = 94%) and increased dialysis dose (Kt/V urea) (14 studies, 2022 participants: MD 0.07, 95% CI -0.00 to 0.14; I(2) = 90%) compared to diffusive therapy, but results across studies were very heterogeneous. Sensitivity analyses limited to studies comparing HDF with HD showed very similar results. Directly comparative data for differing types of convective dialysis were insufficient to draw conclusions.Studies had important risks of bias leading to low confidence in the summary estimates and were generally limited to patients who had adequate dialysis vascular access.

AUTHORS' CONCLUSIONS

Convective dialysis may reduce cardiovascular but not all-cause mortality and effects on nonfatal cardiovascular events and hospitalisation are inconclusive. However, any treatment benefits of convective dialysis on all patient outcomes including cardiovascular death are unreliable due to limitations in study methods and reporting. Future studies which assess treatment effects of convection dose on patient outcomes including mortality and cardiovascular events would be informative.

Pharmacokinetics of doripenem during high volume hemodiafiltration in patients with septic shock

Pharmacokinetics (PK) of doripenem was determined during high volume hemodiafiltration (HVHDF) in patients with septic shock. A single 500 mg dose of doripenem was administered as a 1 hour infusion during HVHDF to 9 patients. Arterial blood samples were collected before and at 30 or 60 minute intervals over 8 hours (12 samples) after study drug administration. Doripenem concentrations were determined by ultrahigh performance liquid chromatography-tandem mass spectrometry. Population PK analysis and Monte Carlo simulation of 1,000 subjects were performed. The median convective volume of HVHDF was 10.3 L/h and urine output during the sampling period was 70 mL. The population mean total doripenem clearance on HVHDF was 6.82 L/h, volume of distribution of central compartment 10.8 L, and of peripheral compartment 12.1 L. Doses of 500 mg every 8 hours resulted in 88.5% probability of attaining the target of 50% time over MIC for bacteria with MIC = 2 µg/mL at 48 hours, when doubling of MIC during that time was assumed. Significant elimination of doripenem occurs during HVHDF. Doses of 500 mg every 8 hours are necessary for treatment of infections caused by susceptible bacteria during extended HVHDF.

The doripenem serum concentrations in intensive care patients suffering from acute kidney injury, sepsis, and multi organ dysfunction syndrome undergoing continuous renal replacement therapy slow low-efficiency dialysis

Doripenem is a novel wide-spectrum antibiotic, and a derivate of carbapenems. It is an ideal antibiotic for treatment of serious nosocomial infections and severe sepsis for its exceptionally high efficiency and broad antibacterial spectrum of action. Doripenem is eliminated mainly by the kidneys. In cases of acute kidney injury, dosing of doripenem depends on creatinine clearance and requires adjustments. Doripenem is eliminated during hemodialysis because its molecular weight is 300–400 Da. The aim of this study was to establish the impact of continuous renal replacement therapy (CRRT) slow low-efficiency dialysis (SLED) on doripenem serum concentrations in a population of intensive-therapy patients with life-threatening infections and severe sepsis. Ten patients were enrolled in this observational study. Twelve blood samples were collected during the first administration of doripenem in a 1-hour continuous infusion while CRRT SLED was provided. Fluid chromatography was used for measurement of the concentration of doripenem in serum. In all collected samples, concentration of doripenem was above the minimum inhibition concentration of this antibiotic. Based on these results, we can draw the conclusion that doripenem concentration is above the minimum inhibition concentration throughout all of CRRT. The dosing pattern proposed by the manufacturer can be used in patients receiving CRRT SLED without necessary modifications.

Pharmacokinetic assessment in patients receiving continuous RRT: perspectives from the Kidney Health Initiative

The effect of AKI and modern continuous RRT (CRRT) methods on drug disposition (pharmacokinetics) and response has been poorly studied. Pharmaceutical manufacturers have little incentive to perform pharmacokinetic studies in patients undergoing CRRT because such studies are neither recommended in existing US Food and Drug Administration (FDA) guidance documents nor required for new drug approval. Action is urgently needed to address the knowledge deficit. The Kidney Health Initiative has assembled a work group composed of clinicians and scientists representing academia, the FDA, and the pharmaceutical and dialysis industries with expertise related to pharmacokinetics, AKI, and/or CRRT. The work group critically evaluated key considerations in the assessment of pharmacokinetics and drug dosing in CRRT, practical constraints related to conducting pharmacokinetic studies in critically ill patients, and the generalizability of observations made in the context of specific CRRT prescriptions and specific patient populations in order to identify efficient study designs capable of addressing the knowledge deficit without impeding drug development. Considerations for the standardized assessment of pharmacokinetics and development of corresponding drug dosing recommendations in critically ill patients with AKI receiving CRRT are proposed.

Doripenem population pharmacokinetics and dosing requirements for critically ill patients receiving continuous venovenous haemodiafiltration

OBJECTIVES

Doripenem is a newer carbapenem with little data available to guide effective dosing during renal replacement therapy in critically ill patients. The objective of this study was to determine the population pharmacokinetics of doripenem in critically ill patients undergoing continuous venovenous haemodiafiltration (CVVHDF) for acute kidney injury (AKI).

METHODS

This was an observational pharmacokinetic study in 12 infected critically ill adult patients with AKI undergoing CVVHDF and receiving 500 mg of doripenem intravenously every 8 h as a 60 min infusion. Serial blood samples were taken on 2 days of treatment and used for population pharmacokinetic analysis with S-ADAPT.

RESULTS

The median (IQR) age was 62 (53-71) years, the median (IQR) weight was 77 (67-96) kg and the median (IQR) APACHE II score was 29 (19-32). The median blood, dialysate and replacement fluid rates were 200, 1000 and 1000 mL/h, respectively. A two-compartment linear model with doripenem clearance described by CVVHDF, renal or non-renal mechanisms was most appropriate. The mean value for total doripenem clearance was 4.46 L/h and volume of distribution was 38.0 L. Doripenem clearance by CVVHDF was significantly correlated with the replacement fluid flow rate and accounted for ∼30%-37% of total clearance. A dose of 500 mg intravenously every 8 h achieved favourable pharmacokinetic/pharmacodynamics for all patients up to an MIC of 4 mg/L.

CONCLUSIONS

This is the first paper describing the pharmacokinetics/pharmacodynamics of doripenem in critically ill patients with AKI receiving CVVHDF. A dose of 500 mg intravenously every 8 h was appropriate for our CVVHDF settings for infections caused by susceptible bacteria.

Doripenem dosing recommendations for critically ill patients receiving continuous renal replacement therapy

Doripenem dosing regimens for patients receiving continuous venovenous hemofiltration (CVVH) and continuous venovenous hemodiafiltration (CVVHDF) were devised based on an established efficacy criterion (free plasma doripenem concentrations above the minimum inhibitory concentration [fT > MIC] of 1 mg/L for ≥35% of the dosing interval) while maintaining exposure below that with the highest studied dose of 1000 mg infused over 1 hour every 8 hours in healthy subjects. Simulations were utilized to assure ≥90% probability of achieving the efficacy criterion with the recommended doripenem regimens. Inflated intersubject variability of 40% (coefficient of variation) was used for pharmacokinetic parameters (representative of clinical variation) and nonrenal clearance was doubled to account for potential changes with acute renal insufficiency. Results indicate that a reduction in doripenem dose will be needed for critically ill patients receiving CVVH or CVVHDF. This work was conducted to fulfill a health authority request and resulted in the addition of dosing recommendations to the Doribax Summary of Product Characteristics.

Evaluation of antibiotic prescribing patterns in patients receiving sustained low-efficiency dialysis: opportunities for pharmacists

OBJECTIVES

Sustained low-efficiency dialysis (SLED) is a 'hybrid' form of continuous renal replacement therapy; however, there is very limited information on drug disposition during this procedure. Individuals requiring SLED are often critically ill and require antibiotics. The study aim was to evaluate antibiotic orders for patients requiring SLED compared to literature-based recommendations. We also evaluated whether doses were administered as prescribed and assessed clinical and microbiologic cure.

METHODS

A retrospective review was performed over a 2-year period for patients who received concurrent SLED and antibiotic therapy. Demographic data, prescribed antibiotic dosing regimens and doses delivered as prescribed were determined for 10 antibiotics: cefepime (C), daptomycin (Da), doripenem (D), gentamicin (G), imipenem-cilastatin (I), linezolid (L), meropenem (M), piperacillin-tazobactam (P), tobramycin (T) and vancomycin (V). Dosing regimens were compared to recommendations from the literature where available. The incidence of clinical and microbiologic cure was also evaluated.

RESULTS

A total of 87 patients met inclusion criteria: mean age 54 ± 14 years, 60% male, 58% white. Prescribed doses were evidence-based for 37% of Da, 97% of L, 15% of M and 7% of V orders. The majority of discrepancies were due to under-dosing. There were 129 (11%) antibiotic doses missed. Of the 13 patients who met criteria for assessment of clinical and microbiologic cure, 10 achieved a microbiologic cure and none reached clinical cure.

CONCLUSIONS

Prescribed antibiotic dosing regimens varied substantially and under-dosing was common. There is a need to further define appropriate dosing regimens for antibiotics administered during SLED and determine how pharmacists may help to ensure appropriate therapy.

Newer beta-lactam antibiotics: doripenem, ceftobiprole, ceftaroline, and cefepime

This article reviews the new beta-lactam (β-lactam) antibiotics doripenem, ceftobiprole, and ceftaroline. It covers pharmacokinetic and pharmacodynamic properties, dosing, in vitro activities, safety, and clinical trial results. Doripenem (Doribax) has been approved by the US Food and Drug Administration (FDA) for the treatment of complicated intra-abdominal and urinary tract infections. Ceftaroline has received FDA approval for the treatment of skin and soft tissue infections and community acquired pneumonia. Ceftobiprole has not received FDA approval. The article also reviews recent data suggesting increased overall mortality with Cefepime (Maxipime) use compared with other beta-lactam antibiotics and the potential risk for neurotoxicity in the setting of renal failure.