Population pharmacokinetic rationale for intravenous contezolid acefosamil followed by oral contezolid dosage regimens.

Contezolid is a novel oxazolidinone antibiotic with a promising safety profile. Oral contezolid and its intravenous (IV) prodrug contezolid acefosamil (CZA) are in development for treatment of diabetic foot and acute bacterial skin and skin structure infections (ABSSSI). The prodrug CZA is converted to active contezolid via intermediate MRX-1352. This study aimed to provide the pharmacokinetic rationale for safe, effective, and flexible dosage regimens with initial IV CZA followed by oral contezolid. We simultaneously modeled plasma concentrations from 110 healthy volunteers and 74 phase 2 patients with ABSSSI via population pharmacokinetics (using the importance sampling estimation algorithm), and optimized dosage regimens by Monte Carlo simulations. This included data on MRX-1352, contezolid, and its metabolite MRX-1320 from 66 healthy volunteers receiving intravenous CZA (150-2400 mg) for up to 28 days, and 74 patients receiving oral contezolid [800 mg every 12 h (q12h)] for 10 days. The apparent total clearance for 800 mg oral contezolid with food was 16.0 L/h (23.4% coefficient of variation) in healthy volunteers and 17.7 L/h (53.8%) in patients. CZA was rapidly converted to MRX-1352, which subsequently transformed to contezolid. The proposed dosage regimen used an IV CZA 2000 mg loading dose with 1000 mg IV CZA q12h as maintenance dose(s), followed by 800 mg oral contezolid q12h (with food). During each 24-h period, Monte Carlo simulations predicted this regimen to achieve consistent areas under the curve of 91.9 mg·h/L (range: 76.3-106 mg·h/L) under all scenarios. Thus, this regimen was predicted to reliably achieve efficacious contezolid exposures independent of timing of switch from IV CZA to oral contezolid.IMPORTANCEThis study provides the population pharmacokinetic rationale for the dosage regimen of the intravenous (IV) prodrug contezolid acefosamil (CZA) followed by oral contezolid. We developed the first integrated population model for the pharmacokinetics of the MRX-1352 intermediate prodrug, active contezolid, and its main metabolite MRX-1320 based on data from three clinical studies in healthy volunteers and phase 2 patients. The proposed regimen was predicted to reliably achieve efficacious contezolid exposures independent of timing of switch from IV CZA to oral contezolid.

The dosing regimen for 17-hydroxyprogesterone caproate was suboptimal: lessons for future pharmacotherapy for pregnant women.

BACKGROUND: Makena (17-hydroxyprogesterone caproate) was approved by the United States Food and Drug Administration for the prevention of recurrent spontaneous preterm birth in 2011 under the accelerated approval pathway, but fundamental pharmacokinetic or pharmacodynamic (Phase 1 and Phase 2) studies were not performed. At the time, there were no dose-response or concentration-response data. The therapeutic concentration was not known. The lack of such data brings into question the dosing regimen for 17-hydroxyprogesterone caproate and if it was optimized. OBJECTIVE: The purpose of this study was to evaluate the dosing regimen for 17-hydroxyprogesterone by analyzing 3 data sets in which the 17-hydroxyprogesterone caproate pharmacology was evaluated, namely the Maternal-Fetal Medicine Omega 3 study, the Obstetric-Fetal Pharmacology Research Units study, and the Obstetrical-Fetal Pharmacology Research Centers study. If an inappropriate dosing regimen could be identified, such information could inform future studies of pharmacotherapy in pregnancy. STUDY DESIGN: Data from the Omega 3 study were used to determine if plasma concentration was related to spontaneous preterm birth risk and if a threshold concentration could be identified. Data from the Obstetric-Fetal Pharmacology Research Units study were used to determine the half-life of 17-hydroxyprogesterone caproate and to develop a model to simulate drug concentrations with various dosing regimens. Data from the Obstetrical-Fetal Pharmacology Research Centers study were used to determine the relationship between dose and safety outcomes. RESULTS: Analysis of the Omega 3 data set indicated that the risk for spontaneous preterm birth decreased as the log concentration of 17-hydroxyprogesterone caproate increased (odds ratio, 0.04; 95% confidence interval, 0.00-0.90). A steady state concentration of >9 ng/mL (equivalent to >8 ng/mL at 25-28 weeks) was associated with the lowest risk for spontaneous preterm birth (hazard ratio, 0.52; 95% confidence interval, 0.27-0.98; P=.04); this concentration was not achieved in 25% of subjects who received the 250 mg weekly dose. In the Obstetrical-Fetal Pharmacology Research Units study, the adjusted half-life (median and interquartile range) of 17-hydroxyprogesterone caproate was 14.0 (11.5-17.2) days. Simulations indicated that with the 250 mg weekly dose, >5 weekly injections were required to reach the 9 ng/mL target; however, those with the shortest half-life (corresponding to higher clearance), never reached the targeted 9 ng/mL concentration. In 75% of subjects, a loading dose of 500 mg weekly for 2 weeks followed by 250 mg weekly achieved and maintained the 9 ng/mL concentration within 2 weeks but in those 25% with the shortest half-life, concentrations exceeded the 9 ng/mL target for only 3 weeks. In the Obstetrical-Fetal Pharmacology Research Centers study, all 65 subjects who received a weekly dose of 500 mg exceeded the 9 ng/mL steady state. CONCLUSION: The dosing regimen for 17-hydroxyprogesterone caproate was inadequate. There is a significant inverse relationship between drug concentration and spontaneous preterm birth. The risk was lowest when the concentration exceeded 9 ng/mL, but 25% of women who received the 250 mg weekly dose never reached or maintained this concentration. The drug's long half-life necessitates a loading dose to achieve therapeutic concentrations rapidly. The omission of basic pharmacologic studies to determine the proper dosing may have compromised the effectiveness of 17-hydroxyprogesterone caproate. Future pharmacotherapy trials in pregnancy must first complete fundamental pharmacology studies.

Model-based dosing optimization and therapeutic drug monitoring practices of teicoplanin in patients with complicated or non-complicated methicillin-resistant staphylococcus aureus infection.

AIMS: This study aims to establish a population pharmacokinetic (PK) model of teicoplanin in Chinese adult patients to evaluate the dosing regimen in the label sheet and optimize it. METHODS: Nonlinear mixed-effects modelling was used to estimate PK parameters. Monte Carlo simulations were used to evaluate the attainment of various dosing regimens in achieving the target trough concentrations in patients with normal or decreased renal function. RESULTS: A total of 115 patients were enrolled in this retrospective study. Creatinine clearance (CrCL) and albumin (ALB) were identified as covariates on the clearance of teicoplanin. For the treatment of non-complicated methicillin-resistant Staphylococcus aureus (MRSA) infections in patients with normal renal function and serum ALB concentration, the recommended dosing regimen was 600 mg q12h with five administrations as the loading dose followed by 600 mg qd as the maintenance dose; for the treatment of serious and/or complicated MRSA infections, the recommended dosing regimen was 800 mg q12h with five administrations as the loading dose followed by 800 mg qd as the maintenance dose. It is worth noting that both the loading and maintenance doses ought to be modified based on the patient's renal function and serum ALB concentration. In addition, trough concentrations of teicoplanin were significantly increased every other week. CONCLUSIONS: Both loading dosing and maintenance dosing regimens were recommended to be adjusted according to patient's renal function and serum ALB concentration. In addition, it is necessary to perform follow-up therapeutic drug monitoring of teicoplanin at least once every week.

Comparative Safety and Effectiveness of Loading Doses of P2Y12 Inhibitors in Patients Undergoing Elective PCI: a Network Meta-analysis.

PURPOSE: Effective platelet inhibition prior to elective percutaneous coronary intervention (PCI) reduces the risk of ischemic complications. Newer P2Y12 inhibitors are preferred agents over clopidogrel for patients presenting with the acute coronary syndrome. However, the comparative efficacy and safety of them over clopidogrel in elective PCI is unclear. We performed a network meta-analysis to compare the safety and efficacy of loading strategies of P2Y12 inhibitors in patients undergoing elective PCI. METHODS: We conducted a systematic review of randomized controlled trials (RCT) up to June 2021 to compare the safety and effectiveness of different loading strategies of P2Y12 inhibitors before elective PCI. The endpoints of interest were overall mortality, rates of myocardial infarction (MI), stroke, revascularization, and major bleeding. Random effects model using the frequentist approach was used to perform a network meta-analysis using R software. RESULTS: Five trials with a total of 5194 patients were included in our analysis. For ischemic outcomes, including MI, stroke, and revascularization, prasugrel had the most favorable trend. However, clopidogrel had the highest probability of being most effective for major bleeding and all-cause mortality. None of these trends was statistically significant due to lack of power for each outcome. CONCLUSION: Although prasugrel and ticagrelor are known as more potent antiplatelet agents, their effects in preventing MI and stroke are marginal and do not translate into improved overall mortality and bleeding compared with clopidogrel.

Trends in Implementation of Loading Dose of Voriconazole from 2010 to 2019 and Influencing Factors of Loading Dose Based on a Japanese Administrative Claim Database: A Retrospective Cohort Study.

A loading dose of voriconazole (VRCZ) is recommended to increase its blood concentration at an early stage. However, the trends in the implementation of the loading dose in VRCZ in Japan has not yet been clarified. In addition, although pharmacists play many important roles in antimicrobial stewardship, the effect of pharmacist intervention on the implementation of a loading dose of VRCZ has not yet been reported. Therefore, this study aimed to clarify the implementation of loading dose of VRCZ and the influencing factors of loading dose. This study used an administrative claims database that included patients who received injectable VRCZ between 2010 and 2019. The implementation of loading doses in the VRCZ was evaluated annually. Multivariate logistic regression analysis was performed to identify the factors influencing loading dose. Overall, 2197 patients were included. The implementation rate of the loading dose remained below 65% throughout the study period. Among medical fees that can be calculated through pharmacist intervention, only the infection prevention and control premium significantly increased the implementation of loading dose of VRCZ (odds ratio: 1.587, 95% confidence interval: 1.053-2.392). In conclusion, antifungal stewardship may have been promoted at medical institutions that established infection prevention and control. In the future, pharmacists will need to intervene more actively from the beginning of VRCZ administration.

Impact of antimicrobial stewardship program-driven educational intervention for vancomycin loading dose on mortality.

BACKGROUND: Although the loading dose (LD) of vancomycin (VCM) contributes to its efficacy, it may not be conducted adequately. Herein, the objective was to evaluate the effect of LD on patient prognosis using therapeutic drug monitoring by pharmacists and elucidate the impact of an antimicrobial stewardship program (ASP)-driven educational intervention on the LD implementation rate and patient prognosis. MATERIALS AND METHODS: First, a retrospective cohort study was conducted involving 121 adult patients administered with VCM and compared with 28-day mortality in LD and non-LD groups. To avoid confounding, the propensity score method was employed. Second, post-training with ASP-driven lectures, a questionnaire survey was conducted for healthcare workers, including physicians, nurses, and pharmacists. The rates of VCM LD implementation and 28-day mortality were compared during a period of one year and 9 months between the pre-ASP (n = 38) and post-ASP (n = 33) groups. RESULTS: After propensity score matching, the 28-day mortality in the LD group was significantly improved, suggesting that the early increase in blood levels of VCM due to an LD is an important factor influencing patient prognosis. After the lecture, a questionnaire survey revealed that the understanding rates of "well" and "slightly well" for educational lectures exceeded 80% of all healthcare workers. The rate of LD implementation significantly increased to 63.6% (21/33) in the post-ASP group compared with 31.6% (12/38) in the pre-ASP group (p = 0.007), and the 28-day mortality declined from 23.7% (9/38) to 6.1% (2/33) (p = 0.041). CONCLUSION: This method of ASP-driven educational intervention would facilitate LD implementation, improving patient prognosis.

Optimal regimen of levetiracetam for prevention of busulfan-induced seizure in patients undergoing hematopoietic stem cell transplantation: A review of available evidence.

OBJECTIVE: This review aimed to summarize the available data and offer a practical recommendation regarding the optimal regimen of levetiracetam (LEV) for the prevention of busulfan-induced seizure (BIS) in patients undergoing hematopoietic stem cell transplantation (HSCT). DATA SOURCES: Published articles by searching databases (PubMed, Google Scholar, Cochrane Library, ScienceDirect) were reviewed. All types of original studies performed in pediatric and adult populations have been investigated and required data was extracted. DATA SUMMARY: Eleven articles were eligible to be included in this review. A loading dose was not used in any of the studies. LEV had been started from 6 to 48 h before busulfan (Bu) initiation and continued up to 24 to 48 h after its termination. The dose range of LEV was 10 to 20 mg/kg/day divided every 12 h in pediatrics and 500 to 1000 mg twice daily in adults. Both oral and intravenous (IV) routes of administration were used. Except for three studies, no seizure had occurred in patients who had received LEV. CONCLUSIONS: Considering the available evidence, LEV with the dose range from 500 to 1000 mg twice daily in adults and 10 mg/kg twice daily (20 mg/kg/day in 2 divided doses) in children orally or IV started from 6 to 24 h before Bu initiation up to 24 to 48 h after the last dose of Bu seems to prevent BIS appropriately. More prospective clinical trials with a larger population are needed to validate the optimal dosing of LEV for BIS prophylaxis in patients undergoing HSCT.

Individualized optimization of colistin loading doses.

Colistin remains one of the few available options for the treatment of infections caused by resistant bacteria. Pharmacokinetic (PK) studies have been successful in estimating the appropriate colistin methanesulfonate (CMS) dose to achieve a target colistin concentration. Currently, there is a consensus that the dose of CMS should vary according to the patient renal function since CMS is mainly eliminated by renal route. For this same reason, the loading dose should vary according to the patient's renal capacity; however, this is not the current clinical practice. In this study we develop a framework to determine two key parameters for the loading dose regimen: (1) the optimal dose according to the characteristics (renal function and weight) of the patient; (2) the waiting time before the maintenance dose. Based on a previous PK model, our framework allows a fast parameter sweep so as to select optimal loading dose and waiting time minimizing the deviation between the plasma concentration and a target value. The results showed that patients presenting low creatinine clearance (CrCL) should receive a lower CMS loading dose with longer interval to start maintenance treatment to avoid nephrotoxic colistin concentrations. In cases of high CrCL, the dose should be higher and the interval to the next dose shorter to avoid subtherapeutic concentrations. Optimization of the loading dose should considerably improve colistin therapy, as the target concentration is reached more quickly, without reaching toxic values.

The necessity of a loading dose when prescribing intravenous colistin in critically ill patients with CRGNB-associated pneumonia: a multi-center observational study.

BACKGROUND: The importance or necessity of a loading dose when prescribing intravenous colistin has not been well established in clinical practice, and approximate one-third to half of patients with carbapenem-resistant gram-negative bacteria (CRGNB) infection did not receive the administration of a loading dose. The aim of this study is to investigate the efficacy and risk of acute kidney injury when prescribing intravenous colistin for critically ill patients with nosocomial pneumonia caused by CRGNB. METHODS: This was a multicenter, retrospective study that recruited ICU-admitted patients who had CRGNB-associated nosocomial pneumonia and were treated with intravenous colistin. Then, we classified the patients into colistin loading dose (N = 85) and nonloading dose groups (N = 127). After propensity-score matching for important covariates, we compared the mortality rate, clinical outcome and microbiological eradication rates between the groups (N = 67). RESULTS: The loading group had higher percentages of patients with favorable clinical outcomes (55.2% and 35.8%, p = 0.037) and microbiological eradication rates (50% and 27.3%, p = 0.042) at day 14 than the nonloading group. The mortality rates at days 7, 14 and 28 and overall in-hospital mortality were not different between the two groups, but the Kaplan-Meier analysis showed that the loading group had a longer survival time than the nonloading group. Furthermore, the loading group had a shorter length of hospital stay than the nonloading group (52 and 60, p = 0.037). Regarding nephrotoxicity, there was no significant difference in the risk of developing acute kidney injury between the groups. CONCLUSIONS: The administration of a loading dose is recommended when prescribing intravenous colistin for critically ill patients with nosocomial pneumonia caused by CRGNB.

Enhanced loading dose of teicoplanin for three days is required to achieve a target trough concentration of 20 µg/mL in patients receiving continuous venovenous haemodiafiltration with a low flow rate.

INTRODUCTION: Because of its lower risk of renal toxicity than vancomycin, teicoplanin is the preferred treatment for methicillin-resistant Staphylococcus aureus infection in patients undergoing continuous venovenous haemodiafiltration (CVVHDF) in whom renal function is expected to recover. The dosing regimen for achieving a trough concentration (Cmin) of ≥20 µg/mL remains unclear in patients on CVVHDF using the low flow rate adopted in Japan. METHODS: The study was conducted in patients undergoing CVVHDF with a flow rate of <20 mg/kg/h who were treated with teicoplanin. We adopted three loading dose regimens for the initial 3 days: the conventional regimen, a high-dose regimen (four doses of 10 mg/kg), and an enhanced regimen (four doses of 12 mg/kg). The initial Cmin was obtained at 72 h after the first dose. RESULTS: Overall, 60 patients were eligible for study inclusion. The proportion of patients achieving the Cmin target was significantly higher for the enhanced regimen than for the high-dose regimen (52.9% versus 8.3%, p = 0.003). In multivariate analysis, the enhanced regimen (odds ratio [OR] = 39.93, 95% confidence interval [CI] = 5.03-317.17) and hypoalbuminaemia (OR = 0.04, 95% CI = 0.01-0.44) were independent predictors of the achievement of Cmin ≥ 20 µg/mL. CONCLUSIONS: An enhanced teicoplanin regimen was proposed to treat complicated or invasive infections by methicillin-resistant Staphylococcus aureus in patients receiving CVVHDF even with a low flow rate.

Hemoadsorption with CytoSorb® and the early course of linezolid plasma concentration during septic shock.

Hemoadsorption with CytoSorb® becomes increasingly established in treatment of various, predominantly inflammation-associated diseases. In septic shock, results suggest improvements in hemodynamics and organ function. However, little is known about the in vivo adsorption properties for various antibiotics. We present the case of a 61-year-old female patient with known Ulrich Turner syndrome who treated supportively with CytoSorb® and with linezolid due to a Staphylococcus epidermidis bloodstream infection as part of her intensive care treatment for septic shock. After establishment of a new adsorber, 600 mg of linezolid administered over 1 h. Linezolid levels measured before adsorber inlet (cpre) and after adsorber outlet (cpost) at 0, 15, 60, 120 and 480 min after starting infusion. Out of the ten samples, only the cpre samples 60 min (3.25 mg/l) and 120 min (4.7 mg/l) showed sufficiently high linezolid levels (therapeutic range 3-9 mg/l). After 480 min, cpre decreased to 2.8 mg/l, cpost increased to 1.85 mg/l, and thus clearance decreased to 67.86 ml/min (from 200 ml/min at 60 min), with greatly reduced adsorption capacity of CytoSorb® after 8 h. A loading dose (additional 600 mg) would have been urgently needed. Linezolid therapy under hemadsorption with CytoSorb® requires a clear indication and close monitoring of levels to avoid underdosing.

Safety, tolerability, and pharmacokinetics of weight-based IV loading dose of lacosamide in the ICU.

Among the newer antiseizure medications, lacosamide (LCM) has been increasingly used for acute seizures and status epilepticus in intensive care unit (ICU). We reviewed retrospectively weight-based dosing of IV LCM in patients admitted to ICU with acute seizures and status epilepticus. We have analyzed 354/382 patient treated with IV LCM in ICU during the years 2013-2016. Data collected were age, total body weight, body mass index (BMI), loading dose, post-IV infusion LCM blood level, duration of infusion, blood pressure, heart rate, oxygen saturation, mean arterial pressures, and documented initiation of pressor agents during or within in 30 min of infusion. Larger doses >8 mg/kg of IV LCM that can be safely administered in ICU patients produce effective plasma levels of 15-20 µg/ml with relatively constant volume of distribution.

Loading dose and efficacy of continuous or extended infusion of beta-lactams compared with intermittent administration in patients with critical illnesses: A subgroup meta-analysis and meta-regression analysis.

WHAT IS KNOWN AND OBJECTIVE: The role of continuous/extended beta-lactam infusions (CEIs) in improving clinical outcomes among critically ill patients remains controversial. Therefore, we aimed to compare the clinical efficacy of CEI versus intermittent administration (IA) of beta-lactams by performing a systematic review and meta-analysis. METHODS: PubMed, the Cochrane Library and Embase were searched from inception until December 2018 for studies comparing clinical outcomes of CEI versus IA in critically ill patients. The meta-analysis included 18 randomized controlled trials (RCTs) and 13 non-RCTs. RESULTS AND DISCUSSION: For CEI versus IA, the summary relative risk (RR) for overall mortality and clinical cure was 0.82 (95% confidence interval [CI]: 0.72-0.94) and 1.31 (95% CI: 1.15-1.49), respectively. Subgroup and meta-regression analyses of the loading dose revealed a significantly increased clinical cure rate in the loading-dose group (RR: 1.44, 95% CI: 1.22-1.69), which remained significant after adjustments for beta-lactam type, and association between clinical cure and loading dose for clinical cure (RR: 1.47, 95% CI: 1.20-1.80; p = .001). Subgroup analysis of administration type indicated that both groups had low mortality and high clinical cure rates; however, the heterogeneity analysis did not support an association across continuous infusion and extended infusion groups. Subgroup analysis of the Acute Physiology and Chronic Health Evaluation (APACHE) score was conducted; according to APACHE scores ≥ 16, overall mortality and clinical cure significantly differed between CEI and IA. WHAT IS NEW AND CONCLUSION: CEIs with loading-dose treatment may significantly improve the clinical outcomes in critically ill sepsis or septic shock patients.

Assessment of micafungin loading dosage regimens against Candida spp. in ICU patients by Monte Carlo simulations.

OBJECTIVE: To assess the efficacy of loading dose on micafungin by simulating different dosage regimens. METHODS: A published study of micafungin in ICU patients was employed to simulate nine different dosage regimens which were sorted out three groups in terms of three maintenance doses. Using pharmacokinetic parameters and pharmacodynamic data, 5000-subject Monte Carlo simulations were conducted to simulate concentration-time profiles of micafungin, calculate probabilities of target attainment (PTAs), and cumulative fractions of response (CFRs) in terms of AUC/MIC targets. PTAs were calculated using AUC/MIC cut-offs: 285 (Candida parapsilosis), 3000 (all Candida spp.), and 5000 (non-parapsilosis Candida spp.). PTA or CFR > 90% was considered optimal for a dosage regimen. RESULTS: The concentration-time profiles of micafungin-simulated dosage regimens were obtained. PTA values were over 90% while applying the loading dose in each group of regimens: for Candida albicans and Candida glabrata (AUC/MIC = 5000), all regimens with loading dose provided PTAs of ≥ 90% for MIC ≤ 0.008 mg/L. The PTAs (AUC/MIC = 3000) were over 90% for MIC ≤ 0.008 mg/L in any regimen. However, for MIC inferior to 0.016 mg/L, only loading dosage regimens provided PTAs exceeding 90%. For C. parapsilosis (AUC/MIC = 285), the maximum MIC of achieving a PTA ≥ 90% was 0.25 mg/L both in the regimens of B (150 mg maintenance dose) and C (200 mg maintenance dose) with loading dose. In addition, CFR of any regimen with loading dose was ≥ 90% against C. albicans and C. glabrata. None of the dosage regimens achieved an expected CFR against C. parapsilosis. CONCLUSIONS: The dosage regimen of micafungin which had a loading dose of 1.5 times was more suitable for ICU patients infected by Candida spp.

Variability of voriconazole concentrations in patients with hematopoietic stem cell transplantation and hematological malignancies: influence of loading dose, procalcitonin, and pregnane X receptor polymorphisms.

AIMS: Voriconazole (VCZ) displays highly variable pharmacokinetics affecting treatment efficacy and safety. We aimed to identify the factors affecting VCZ steady-state trough concentration (Cssmin) to provide evidence for optimizing VCZ treatment regimens. METHODS: A total of 510 Cssmin of 172 patients with hematopoietic stem cell transplantation and hematologic malignancies and their clinical characteristics and genotypes of FMO, POR, and PXR were included in this study. RESULTS: In univariate analysis, the standard loading dose of VCZ significantly increased the Cssmin of VCZ (P < 0.001). The Cssmin of VCZ was significantly correlated with patients' total bilirubin (TB) (P < 0.001) and procalcitonin (PCT) (P < 0.001). FMO3 rs2266780 (P = 0.025), POR rs10954732 (P = 0.015), PXR rs2461817 (P = 0.010), PXR rs7643645 (P = 0.003), PXR rs3732359 (P = 0.014), PXR rs3814057 (P = 0.005), and PXR rs6785049 (P = 0.013) have a significant effect on Cssmin of VCZ. Loading dose, TB, PCT level, and PXRrs3814057 polymorphism were independent influencing factors of VCZ Cssmin in the analysis of multivariate linear regression. And loading dose, PCT, and PXR rs3814057 had significant effects on the probability of the therapeutic window of VCZ. CONCLUSION: The high variability of VCZ Cssmin may be partially explained by loading dose, liver function, inflammation, and PXR polymorphisms. This study suggests the VCZ standard loading dose regimen significantly increased Cssmin and probability of the therapeutic window providing treatment benefits. Patients in the high PCT group may be more likely to exceed 5.5 µg/mL, thus suffering from VCZ toxicity.

Retrospective study on clinical efficacy and safety for daptomycin intermittent doses with or without loading dose in renal failure patients.

This retrospective study is to evaluate the efficacy and safety of daptomycin (DAP) intermittent doses and the effectiveness of DAP loading dose in renal failure patients received DAP intermittent doses. One hundred and ninety-seven patients received DAP for at least 3 days from 2014 to 2017. Clinical and microbiological outcomes and the safety were assessed. A total of 183 patients (93, 60 and 30 patients received DAP daily dose, every 48 h dose and thrice per week dose) were included. DAP intermittent doses, such as every 48 h dose (28.3%) and thrice per week dose (30.0%), showed significantly higher mortality rates than that of DAP daily dose (6.5%) (p = 0.0320). Especially for bacteremia patients, significantly higher mortality was admitted, compared with patients received DAP daily doses (p = 0.0160). Moreover, patients received DAP intermittent doses were admitted slower improvements of their inflammation after DAP therapy started, compared with patients received daily dose. Additionally, DAP loading dose for renal failure patients decreased their mortality and improved patients' inflammation early. Especially for patients received DAP thrice per week dose, they showed significantly lower mortality than patients received non-loading dose (p = 0.0306). Additionally, these clinical enhancements of DAP therapy with loading dose were admitted without any enhancements of its adverse effect risks, except alkaline phosphatase elevation, compared with non-loading dose. In conclusion, DAP intermittent doses showed poor clinical outcomes, compared with daily dose. Then, DAP loading dose would be better clinical option for patients received DAP intermittent doses.

Vancomycin loading dose is associated with increased early clinical response without attainment of initial target trough concentration at a steady state in patients with methicillin-resistant Staphylococcus aureus infections.

WHAT IS KNOWN AND OBJECTIVE: Vancomycin therapeutic guidelines suggest a loading dose of 25-30 mg/kg for seriously ill patients. However, high-quality data to guide the use of loading doses are lacking. We aimed to evaluate whether a loading dose (a) achieved a target trough concentration at steady state and (b) improved early clinical response. METHODS: Patients with an estimated glomerular filtration rate ≥ 90 mL/min/1.73 m2 were included. A loading dose of 25 mg/kg vancomycin followed by 15 mg/kg twice daily was compared with traditional dosing. A Cmin sample was obtained before the fifth dose. An early clinical response 48-72 hours after the start of therapy and clinical success at end of therapy (EOT) was evaluated in patients with methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase-negative Staphylococci or Enterococcus faecium. RESULTS: There was no significant difference in Cmin between the regimen with and without a loading dose (median: 10.4 and 10.2 µg/mL, P = .54). Proportions of patients achieving 10-20 and 15-20 µg/mL were 56.9% and 5.6%, respectively, in patients with a loading dose. Although there was no significant difference in success rate at EOT between groups, a loading dose was associated with increased early clinical response for all infections (adjusted odds ratio [OR]: 4.588, 95% confidence interval [CI]: 1.373-15.330) and MRSA infections (OR: 12.065, 95% CI: 1.821-79.959). Study limitations included no Cmin measurements within 24 hours and the inclusion of less critically ill patients. WHAT IS NEW AND CONCLUSION: A loading dose of 25 mg/kg followed by 15 mg/kg twice daily did not achieve the optimal Cmin at steady state in patients with normal renal function. However, more early clinical responses were obtained with a loading dose compared with traditional dosing, possibly because of a prompt albeit temporary achievement of a more effective concentration.

Comparison of the gamma-Pareto convolution with conventional methods of characterising metformin pharmacokinetics in dogs.

A model was developed for long term metformin tissue retention based upon temporally inclusive models of serum/plasma concentration ([Formula: see text]) having power function tails called the gamma-Pareto type I convolution (GPC) model and was contrasted with biexponential (E2) and noncompartmental (NC) metformin models. GPC models of [Formula: see text] have a peripheral venous first arrival of drug-times parameter, early [Formula: see text] peaks and very slow washouts of [Formula: see text]. The GPC, E2 and NC models were applied to a total of 148 serum samples drawn from 20 min to 72 h following bolus intravenous metformin in seven healthy mongrel dogs. The GPC model was used to calculate area under the curve (AUC), clearance ([Formula: see text]), and functions of time, f(t), for drug mass remaining (M), apparent volume of distribution ([Formula: see text]), as well as [Formula: see text] for [Formula: see text], [Formula: see text] and [Formula: see text]. The GPC models of [Formula: see text] yielded metformin [Formula: see text]-values that were 84.8% of total renal plasma flow (RPF) as estimated from meta-analysis. The GPC [Formula: see text]-values were significantly less than the corresponding NC and E2 [Formula: see text]-values of 104.7% and 123.7% of RPF, respectively. The GPC plasma/serum only model predicted 78.9% drug [Formula: see text] average urinary recovery at 72 h; similar to prior human urine drug [Formula: see text] collection results. The GPC model [Formula: see text] of [Formula: see text], [Formula: see text] and [Formula: see text], were asymptotically proportional to elapsed time, with a constant limiting [Formula: see text] ratio of M/C averaging 7.0 times, a result in keeping with prior simultaneous [Formula: see text] and urine [Formula: see text] collection studies and exhibiting a rate of apparent volume growth of [Formula: see text] that achieved limiting constant values. A simulated constant average drug mass multidosing protocol exhibited increased [Formula: see text] and [Formula: see text] with elapsing time, effects that have been observed experimentally during same-dose multidosing. The GPC heavy-tailed models explained multiple documented phenomena that were unexplained with lighter-tailed models.

Evaluating the optimal dose of teicoplanin with therapeutic drug monitoring: not too high for adverse event, not too low for treatment efficacy.

Therapeutic drug monitoring (TDM) of teicoplanin is aimed at minimizing the clinical impact of pharmacokinetic variability; however, its benefits are still being defined. We performed a retrospective study of teicoplanin TDM focusing on the dose-serum concentration relationship and clinical outcomes in a clinical setting. From January 2017 to December 2018, patients receiving teicoplanin ≥ 72 h with TDM were enrolled. Patients were divided into three groups: non-loading (NL) group, low-dose loading (LD) group (loading dose < 9 mg/kg), and high-dose loading (HD) group (≥ 9 mg/kg). Serum teicoplanin trough concentration (Cmin) and adverse events (AEs) were evaluated in each regimen. A subgroup of patients with bacteremia was analyzed to evaluate clinical efficacy. Among 65 patients, 12, 18, and 35 were grouped in NL, LD, and HD, respectively. Achievement rates of Cmin > 20 mg/L within 10 days were significantly different among the groups (25.0%, 38.9%, and 68.6% in the NL, LD, and HD groups, respectively; P = 0.014). Fourteen patients (21.5%) had AEs, and higher Cmin over 10 days (adjusted odds ratio 2.08 per every 20 mg/L increases, 95% CI 1.13-3.84, P = 0.019) and age ≥ 65 years (P = 0.009) were identified as independent risk factors. In the subgroup analysis, HD regimen (P = 0.050) and high mean Cmin over 10 days (P = 0.025) were significantly associated with treatment success. Although HL regimen could achieve Cmin targets and improve clinical outcome during teicoplanin treatment, high Cmin was associated with AEs during treatment. Routine TDM can be helpful to optimize teicoplanin administration.

Efficacy and Safety of High Loading Dose of Colistin in Multidrug-Resistant Acinetobacter baumannii: A Prospective Cohort Study.

OBJECTIVES: We aimed to assess the efficacy and safety of a high loading dose of colistin and no loading dose of colistin to treat multidrug-resistant (MDR) Acinetobacter baumannii infections. METHODS: We conducted a prospective cohort study of patients with MDR A baumannii infections at a university-affiliated hospital from December 2014 to January 2016. In the high loading dose group, the patients received a high loading dose of 300 mg colistin base activity (CBA) followed by a maintenance dose of 150 mg CBA twice daily, and patients in the no loading dose group received only the maintenance dose. The primary outcome was clinical response. The secondary outcomes were 28-day mortality and microbiological response. RESULTS: A total of 255 cases were identified. The high loading dose of colistin strategy provided no significant difference in good clinical response when compared to the no loading dose group (65.5% vs 70.4%; P = .442), without a significant difference in the development of renal dysfunction (52.3% vs 49.4%; P = .664). However, microbiological eradication was significantly higher among patients who received the high loading dose of colistin when compared to those who received the no loading dose (87.9% vs 70.4%; P = .0006). CONCLUSIONS: The high loading dose of colistin strategy was effective and safe for treating patients with MDR A baumannii.