Population Pharmacokinetic Analysis and Dosing Optimization of Colistin Sulfate in Lung Transplant Recipients with Pneumonia: A Prospective Study.

OBJECTIVES: Currently, there is a lack of information on the clinical pharmacokinetics (PK), effectiveness, and safety of colistin sulfate in lung transplant recipients. This study aims to improve colistin sulfate dosing regimens and evaluate its population pharmacokinetics (PopPK) in lung transplant recipients. METHODS: This study evaluated the clinical efficacy, microbiological efficacy, and adverse events of colistin sulfate in lung transplant recipients. The NONMEM program was employed to construct the PopPK model, and Monte Carlo simulations were executed to establish dosing regimens according to the probability of target attainment (PTA). RESULTS: The study included 146 colistin sulfate concentrations, spanning from 0.05 to 4.18 mg/L from 39 lung transplant recipients with multidrug-resistant gram-negative bacteria. 26 (66.67%) patients successfully eradicated bacteria, and 30 (76.92%) patients had clinical cure or improvement. Additionally, only 2 (5.13%) patients developed colistin sulfate-related nephrotoxicity. The PK profile was effectively represented by a one-compartmental model with linear elimination. Creatinine clearance (CrCL) and concomitant furosemide use were recognized as covariates influencing the clearance of colistin sulfate. Based on the PTA results, a daily dosage of 1.5 million IU, divided into 2-3 administrations, could attain a PTA exceeding 90% for MIC ≤ 1 µg/mL at CrCL of about 110 mL/min. However, this regimen would lead to insufficient exposure for MIC ≥ 2 µg/mL. CONCLUSION: The clearance of colistin sulfate is significantly influenced by concomitant furosemide use and renal function. The currently recommended dosing regimens by label sheet may result in subtherapeutic exposure for MIC exceeding 1 mg/L in lung transplant recipients.

δ-catenin promotes Twist1 stabilization in prostate cancer through ubiquitination modification.

Prostate cancer generally has a high long-term survival rate; however, metastatic prostate cancer remains largely incurable despite intensive multimodal therapy. Recent research has identified δ-catenin, a member of the catenin family, as playing a crucial role in the progression of prostate cancer. Nonetheless, the extent to which δ-catenin influences transcription factors associated with epithelial-mesenchymal transition (EMT) has not been thoroughly explored. This study aims to investigate the hypothesis that δ-catenin enhances the stability of Twist1, thereby promoting the migratory and invasive capabilities of prostate cancer cells. Clinical data indicate a strong correlation between δ-catenin and Twist1 expression levels. Western blot analysis confirmed that δ-catenin stabilizes Twist1 and induces ectopic expression. Additionally, δ-catenin was found to reduce Twist1 phosphorylation by inhibiting GSK-3ß activity. Immunoprecipitation analysis suggested that δ-catenin exerts its effect by competing with Twist1 for binding to ubiquitin (Ub). These results highlight the role of δ-catenin in the ubiquitination modification of Twist1, suggesting that the combined presence of δ-catenin and Twist1 could serve as a biomarker for tumor progression in prostate cancer.

Target Attainment and Population Pharmacokinetics of Nirmatrelvir/Ritonavir in Critically Ill Adult Patients.

Background: The population pharmacokinetics of nirmatrelvir/ritonavir (NIR/RIT) has not yet been described for critically ill adult patient. Purpose: This was a prospective observational population pharmacokinetic study of nirmatrelvir/ritonavir (NIR/RIT) in critically ill adult patients and identify optimal dosing regimens. Patients and Methods: The prescription of NIR/RIT is determined by the attending physician and ranges from 150mg/100mg to 300mg/100mg twice a day. Two to three serial blood samples were collected for each patient after the second doses. We developed and validated PK model for plasma NIR and plasma RIT. Monte Carlo dosing simulations were performed to assess target attainment. Results: We analyzed 89 plasma samples from 31 adult patients. The data were best described by a one-compartment model. Among the covariates tested on pharmacokinetic parameters, creatinine clearance (CrCL) and area under curve (AUC) of RIT had a significant effect on apparent clearance (CL/F) of NIR. Mean (SD) parameters estimates for the absorption rate constant (Ka), apparent distribution (V/F) and CL/F were 0.42 (0.10) h-1. 36.5 (8.5) L, 3.6 (0.26) L/h, respectively. Dosing simulations showed that the target in vitro 90% effective concentration (EC90) was more likely to be achieved twice a day than once a day at the same daily dose of NIR. High CrCL, low AUC of RIT were associated with a reduced likelihood of NIR reaching the target EC90. Conclusion: Based on our dosing simulations, the initial dosage of NIR/RIT was 300mg/100mg twice a day in critically ill patients with CrCL>45 mL/min; When CrCL in critically ill patients is between 15 and 45 mL/min, NIR/RIT is 150mg/100mg twice a day. The maintenance dose is adjusted according to CrCL and AUC of RIT, with the dosages varying between 75mg/100mg and 300mg/100mg.

Risk of immune system and skin and subcutaneous tissue related adverse events associated with oxaliplatin combined with immune checkpoint inhibitors: a pharmacovigilance study.

Background: Few studies have analysed oxaliplatin-induced adverse events (ADEs) in the immune system and skin and subcutaneous tissues through pharmacovigilance. We used this approach to analyse the risk of such ADEs when oxaliplatin combined with immune checkpoint inhibitors (ICIs). Methods: We evaluated the association between oxaliplatin and ADEs in the immune system and skin and subcutaneous tissues using the reporting odd ratio (ROR) for mining the ADE report signals in the FDA Adverse Event Reporting System database. Risk factors were analyzed using a binary logistic regression analysis using the sex and age of the patients. Results: There were 40,474 reports of oxaliplatin as primary suspect drug or second suspect drug. The signal intensities of ADEs such as type II hypersensitivity, type I hypersensitivity, type III immune complex-mediated reaction, anaphylactoid shock and cytokine release syndrome were high in PTs classified by SOC as immune system disorders; in the PTs classified as skin and subcutaneous tissue disorders by SOC, the signal intensities of ADEs such as skin toxicity, skin reaction, rash maculo-papular and skin fissures were higher. In the risk assessment between the two groups, rash showed an increased risk in the oxaliplatin-ICI group, with an OR of 1.96. Nivolumab in combination with oxaliplatin had an OR of 2.196 and an adjusted OR of 2.231. Combined with pembrolizumab, OR was 2.762 and the adjusted OR was 2.678. Conclusion: Type II hypersensitivity shows a stronger pharmacovigilance signal. Oxaliplatin in combination with nivolumab or pembrolizumab has been shown to increase the risk of rash.

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.

Simvastatin ameliorates synaptic plasticity impairment in chronic mild stress-induced depressed mice by modulating hippocampal NMDA receptor.

BACKGROUND: In our previous study, we showed simvastatin exerts an antidepressant effect and inhibits neuroinflammation. Given the role of synaptic impairment in depression development, we investigate the effect of simvastatin on synaptic plasticity in depression and the related mechanisms. METHODS: Electrophysiological analysis, Golgi staining, and transmission electron microscope were performed to analyze the effect of simvastatin on synaptic impairment in depression. In addition, the localization and reactivity of N-methyl-D-aspartate receptor (NMDAR) subunits and the downstream signaling were investigated to explore the mechanism of simvastatin's effect on synaptic plasticity. RESULTS: Simvastatin ameliorated the reduction of the magnitude of long-term potentiation (LTP) in Schaffer collateral-CA1, restored hippocampal dendritic spine density loss, improved the number of spine synapses, reversed the reduction in BrdU-positive cells in chronic mild stress (CMS)-induced depressed mice, and ameliorated NMDA-induced neurotoxicity in hippocampal neurons. Dysfunction of NMDAR activity in the hippocampus is associated with depression. Simvastatin treatment reversed the surface expression and phosphorylation changes of NMDAR subunits in NMDA-treated hippocampal neurons and depressed mice. In addition, simvastatin further increased the levels of mature BDNF, activating TrkB-Akt-mTOR signaling, which is critical for synaptic plasticity. CONCLUSIONS: These findings suggest that simvastatin can improve the dysfunction of NMDAR and ameliorate hippocampal synaptic plasticity impairment in depressed mice.

Development of UPLC-MS/MS method for the determination of colistin in plasma and kidney and its application in pharmacokinetics.

Recently, the frequent emergence of multidrug-resistant gram-negative bacterial infections has forced colistin to be used as one of the last-line options for the treatment of these infections. This study aimed to establish and validate a simple, rapid, and reliable method for the quantitative determination of colistin in plasma and kidney homogenates by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The pharmacokinetic parameters of colistin sulfate in rats and the relationship between renal accumulation and time of administration in rats were estimated by measuring plasma and renal colistin concentrations. The colistin in the sample was precipitated by acetonitrile, followed by extraction with nitrogen blow-drying and reconstitution. The chromatographic separation of analytes was conducted on an C18 column using a mobile phase consisting of 0.1% aqueous formic acid and acetonitrile. Polymyxin B was used as an internal standard (IS). Colistin and IS were monitored in positive ion mode with the following mass transition pairs: m/z 585.6→m/z 101.4 for colistin A，m/z 578.6→m/z 101.4 for colistin B and m/z 595.6→m/z 227.2 for IS, respectively. The established method expressed good linearity in 50 - 20000 ng·mL-1 of colistin, with the lower limit of quantification (LLOQ) of 50 ng·mL-1. Methodology validations, including accuracy, precision, matrix effect, recovery, stability, and dilution integrity met the US Food and Drug Administration (FDA) acceptance criteria for bioanalytical method validation. Noncompartmental pharmacokinetic parameters were obtained by the statistical moment theory. The estimates for the terminal half-life (t1/2), the peak time (Tmax), the peak concentration (Cmax), the area under the plasma concentration-time curve (AUC0-t), the volume of distribution (V), the total body clearance (CL) and the mean residence time (MRT0-t) were calculated to be 2.53 ± 1.6 h, 2.17 ± 1.57 h, 2913.01 ± 644.89 ng·mL-1, 15153.46 ± 3599.81 h·ng·mL-1, 0.98 ± 0.56 L·kg-1, 0.28 ± 0.09 L·h-1·kg-1 and 4.07 ± 1.13 h, respectively. And the concentrations of colistin in rat kidney tissue after continuous administration for 1, 3, 5, 7 days were 1.49 ± 0.35 µg·g-1, 2.88 ± 0.74 µg·g-1, 3.40 ± 0.25 µg·g-1 and 4.33 ± 0.63 µg·g-1, respectively. The established method provided a convenient, rapid, stable, sensitive, accurate way for the determination of colistin concentration, which has been successfully used for the pharmacokinetic analysis of colistin sulfate in rat and to explore the relationship between the renal accumulation of colistin and the duration of dosing.

Safety and clinical efficacy of linezolid in children: a systematic review and meta-analysis.

BACKGROUND: We aimed to evaluate the tolerability and efficacy of linezolid in children for treating suspected and diagnosed Gram-positive bacterial infections. METHODS: A systematic literature search was conducted up to April 23, 2021, using linezolid and its synonyms as search terms. Two reviewers independently identified and extracted relevant randomized controlled trials and prospective cohort studies. The extracted studies were included in a single-rate meta-analysis of adverse events and clinical outcomes using random-effects models. RESULTS: A total of 1082 articles were identified, and nine studies involving 758 children were included in the meta-analysis. The overall proportion of adverse events was 8.91% [95% confidence interval (CI) = 1.64%-36.52%], with diarrhea (2.24%), vomiting (2.05%), and rash (1.72%) being the most common. The incidences of thrombocytopenia and anemia were 0.68% and 0.16%, respectively. Some specific adverse events, including rash and gastrointestinal events, were more frequent in the oral administration subgroup. In terms of efficacy, the overall proportion of clinical improvement was 88.80% (95% CI = 81.31%-93.52%). Children with a history of specific bacteriological diagnosis or concomitant antibiotic therapy had a 1.13-fold higher clinical improvement than children without such histories. The proportion of microbial eradication was 92.68% (95% CI = 84.66%-96.68%). The proportion of all-cause mortality was 0.16% (95% CI = 0.00%-7.75%). CONCLUSIONS: Linezolid was well-tolerated in pediatric patients and was associated with a low frequency of adverse events, such as anemia, thrombocytopenia, and neutropenia. Moreover, linezolid was effective in children with diagnosed and suspected Gram-positive infections.

Modification of Vancomycin Dosing in Cardiac Surgery With Cardiopulmonary Bypass.

This study aims to assess the risk factors for insufficient vancomycin concentrations for its prophylactic use in adult patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) and to modify the dosing regimen to achieve appropriate plasma concentrations. A total of 27 patients with vancomycin dosing of 1 to 1.5 g based on a weight cutoff of 67 kg were included, of which only 13 (48.15%) had vancomycin plasma concentration >15 mg/L at surgical closure. Risk factors of vancomycin concentration <15 mg/L at surgical-site closure were confirmed by multivariate logistic regression analysis, which showed that CPB duration was an independent predictor. Patients with CPB duration >4 hours had significantly lower vancomycin concentrations and lower proportion in achieving target vancomycin concentration at the end of CPB and surgical closure. For patients with CPB >4 hours, the modified dosing regimen that a second dose of 0.5 to 0.75 g added at 4 hours since the onset of CPB improved the target achievement of vancomycin concentration at surgical closure. Taken together, CPB duration >4 hours was the risk factor for insufficient vancomycin concentration at surgical closure, while our modified dosing could improve the vancomycin concentrations for its prophylactic use in patients undergoing cardiac surgery with CPB.

Hippocampal Galectin-3 knockdown alleviates lipopolysaccharide-induced neurotoxicity and cognitive deficits by inhibiting TLR4/NF-кB signaling in aged mice.

Neuroinflammation is thought to contribute to the onset and progression of Alzheimer's disease (AD). Galectin-3 (Gal-3), the only member of the galectin chimeric subfamily, is a key regulator of neuroinflammation and microglial activation. However, the effects of Gal-3 inhibition in AD-related neuroinflammation are unclear. Here, we investigated whether hippocampal Gal-3 knockdown alleviated lipopolysaccharide (LPS)-induced neurotoxicity and cognitive deficits, as well as the underlying mechanisms. First, we bilaterally injected aged mice (23 months old) with anti-Gal-3 short hairpin RNA into the hippocampus dentate gyrus, followed by systemic LPS administration. To determine the effects of hippocampal Gal-3 knockdown on neuroinflammatory response and neuronal apoptosis, we assessed the effects of Gal-3 silencing on the levels of pro-inflammatory cytokines, microglial activation, and apoptosis in the hippocampus of LPS-exposed aged mice. Behavioral tests were used to access the cognitive function of the mice. To explore the potential signaling, protein extracts from the brains of mice were subjected to analyze the expression levels of key molecules (including Toll-like receptor 4 (TLR4), myeloid differentiation factor 88, and nuclear transcription factor-κB (NF-κB) p65) of the TLR4/NF-кB pathway, and BV2 cells were pretreated with TLR4 inhibitor or NF-κB inhibitor before Gal-3 stimulation. These analyses showed that hippocampal Gal-3 knockdown attenuated neuroinflammation and neuronal apoptosis in the hippocampus of LPS-challenged aged mice, and this was associated with improved cognitive function. Hippocampal Gal-3 knockdown may protect against LPS-induced neurotoxicity by inhibiting the TLR4/NF-кB pathway. Our findings highlight Gal-3 as a potential therapeutic target against AD-associated neuroinflammation.

Population pharmacokinetic analysis, renal safety, and dosing optimization of polymyxin B in lung transplant recipients with pneumonia: A prospective study.

Objectives: This study aims to characterize the population pharmacokinetics of polymyxin B in lung transplant recipients and optimize its dosage regimens. Patients and methods: This prospective study involved carbapenem-resistant organisms-infected patients treated with polymyxin B. The population pharmacokinetic model was developed using the NONMEM program. The clinical outcomes including clinical treatment efficacy, microbiological efficacy, nephrotoxicity, and hyperpigmentation were assessed. Monte Carlo simulation was performed to calculate the probability of target attainment in patients with normal or decreased renal function. Results: A total of 34 hospitalized adult patients were included. 29 (85.29%) patients were considered of clinical cure or improvement; 14 (41.18%) patients had successful bacteria elimination at the end of the treatment. Meanwhile, 5 (14.71%) patients developed polymyxin B-induced nephrotoxicity; 19 (55.88%) patients developed skin hyperpigmentation. A total of 164 concentrations with a range of 0.56-11.66 mg/L were obtained for pharmacokinetic modeling. The pharmacokinetic characteristic of polymyxin B was well described by a 1-compartment model with linear elimination, and only creatinine clearance was identified as a covariate on the clearance of polymyxin B. Monte Carlo simulations indicated an adjusted dosage regimen might be needed in patients with renal insufficiency and the currently recommended dose regimens by the label sheet of polymyxin B may likely generate a subtherapeutic exposure for MIC = 2 mg/L. Conclusion: Renal function has a significant effect on the clearance of polymyxin B in lung transplant recipients, and an adjustment of dosage was needed in patients with renal impairments.

Expert consensus statement on therapeutic drug monitoring and individualization of linezolid.

Linezolid is an oxazolidinone antibacterial drug, and its therapeutic drug monitoring and individualized treatment have been challenged since its approval. With the in-depth clinical research of linezolid, we have changed our attitude toward its therapeutic drug monitoring and our view of individualized treatment. On the basis of summarizing the existing clinical studies, and based on the practical experience of each expert in their respective professional fields, we have formed this expert consensus. Our team of specialists is a multidisciplinary team that includes pharmacotherapists, clinical pharmacology specialists, critical care medicine specialists, respiratory specialists, infectious disease specialists, emergency medicine specialists and more. We are committed to the safe and effective use of linezolid in patients in need, and the promotion of its therapeutic drug monitoring.

Population Pharmacokinetics of Colistin Sulfate in Critically Ill Patients: Exposure and Clinical Efficacy.

Background: Presently, colistin is commercially available in two different forms, namely, colistin sulfate and its sulphomethylated derivative, colistimethate sodium (CMS). However, in the currently reported studies, most of the clinical studies on colistin for parenteral use are referred to as CMS. Data on the pharmacokinetics (PK), clinical efficacy, and side effects of colistin sulfate in clinical use have not been reported. Methods: This retrospective study was performed on carbapenem-resistant organism (CRO)-infected patients treated with colistin sulfate for more than 72 h. The population pharmacokinetic model was developed using the NONMEM program. The clinical outcomes including clinical treatment efficacy, microbiological eradication, and nephrotoxicity were assessed. Monte Carlo simulation was utilized to calculate the probability of target attainment (PTA) in patients with normal or decreased renal function. Results: A total of 42 patients were enrolled, of which 25 (59.52%) patients were considered clinical treatment success and 29 (69.06%) patients had successful bacteria elimination at the end of treatment. Remarkably, no patient developed colistin sulfate-related nephrotoxicity. A total of 112 colistin concentrations with a range of 0.28-6.20 mg/L were included for PK modeling. The PK characteristic of colistin was well illustrated by a one-compartment model with linear elimination, and creatinine clearance (CrCL) was identified as a covariate on the clearance of colistin sulfate that significantly explained inter-individual variability. Monte Carlo simulations showed that the recommended dose regimen of colistin sulfate, according to the label sheet, of a daily dose of 1-1.5 million IU/day, given in 2-3 doses, could attain PTA > 90% for MICs ≤ 0.5 µg/mL, and that a daily dose of 1 million IU/day could pose a risk of subtherapeutic exposure for MIC ≥1 µg/ml in renal healthy patients. Conclusion: Renal function significantly affects the clearance of colistin sulfate. A dose of 750,000 U every 12 h was recommended for pathogens with MIC ≤1 µg/ml. The dosage recommended by the label inserts had a risk of subtherapeutic exposure for pathogens with MIC ≥2 µg/ml. Despite higher exposure to colistin in patients with acute renal insufficiency, dose reduction was not recommended.

Efficacy and Pharmacodynamic Target Attainment for Ceftazidime-Avibactam Off-Label Dose Regimens in Patients with Continuous or Intermittent Venovenous Hemodialysis: Two Case Reports.

Limited data are available for ceftazidime-avibactam (CZA) dosing in patients receiving renal replacement therapy, especially the data on the dosing in patients receiving intermittent hemodialysis (IHD). In this report, we firstly described a case in which CZA was administered as 2.5 g after each time of IHD, and a dose of 1.25 g was added on the 48th-hour for the 72-h interdialytic interval. Plasma concentrations of CZA measured at different time indicated that > 50% of administered ceftazidime and avibactam were removed during the 4-h hemodialysis. In addition, we described another case on continuous venovenous hemodialysis (CVVHD), in which CZA was administered as 2.5 g q12h in 2-h infusions. The dose regimen for these two cases could achieve trough concentration of ceftazidime higher than fourfold of the MIC and trough concentration of avibactam higher than the threshold of 1 µg/mL during the treatment, and exert efficient antimicrobial effect.

Dosage Strategy of Linezolid According to the Trough Concentration Target and Renal Function in Chinese Critically Ill Patients.

Background: Linezolid is associated with myelosuppression, which may cause failure in optimally treating bacterial infections. The study aimed to define the pharmacokinetic/toxicodynamic (PK/TD) threshold for critically ill patients and to identify a dosing strategy for critically ill patients with renal insufficiency. Methods: The population pharmacokinetic (PK) model was developed using the NONMEM program. Logistic regression modeling was conducted to determine the toxicodynamic (TD) threshold of linezolid-induced myelosuppression. The dosing regimen was optimized based on the Monte Carlo simulation of the final model. Results: PK analysis included 127 linezolid concentrations from 83 critically ill patients at a range of 0.25-21.61 mg/L. Creatinine clearance (CrCL) was identified as the only covariate of linezolid clearance that significantly explained interindividual variability. Thirty-four (40.97%) of the 83 patients developed linezolid-associated myelosuppression. Logistic regression analysis showed that the trough concentration (Cmin) was a significant predictor of myelosuppression in critically patients, and the threshold for Cmin in predicting myelosuppression with 50% probability was 7.8 mg/L. The Kaplan-Meier plot revealed that the overall median time from the initiation of therapy to the development of myelosuppression was 12 days. Monte Carlo simulation indicated an empirical dose reduction to 600 mg every 24 h was optimal to balance the safety and efficacy in critically ill patients with CrCL of 30-60 ml/min, 450 mg every 24 h was the alternative for patients with CrCL <30 ml/min, and 600 mg every 12 h was recommended for patients with CrCL ≥60 ml/min. Conclusion: Renal function plays a significant role in linezolid PKs for critically ill patients. A dose of 600 mg every 24 h was recommended for patients with CrCL <60 ml/min to minimize linezolid-induced myelosuppression.

Intraventricular colistin sulphate as a last resort therapy in a patient with multidrug-resistant Acinetobacter baumannii induced post-neurosurgical ventriculitis.

Limited therapeutic options exist for multidrug-resistant/extensively drug-resistant Acinetobacter baumannii (MDR/XDR-Ab) meningitis/ventriculitis. A combination of intravenous and intraventricular (IVT)/intrathecal (IT) polymyxins achieves good therapeutic outcomes for cases of healthcare-associated MDR/XDR-Ab meningitis/ventriculitis. Colistin is commercially available as colistin sulphate and its sulphomethylated derivative. However, the effect and safety of colistin sulphate in the treatment of MDR/XDR-Ab meningitis/ventriculitis has not been reported. We report on a 66-year-old male patient who developed post-neurosurgical ventriculitis caused by MDR-Ab. IVT concomitant intravenous colistin sulphate was used as a last-resort antimicrobial therapy, the patient's ventriculitis was dramatically improved, and the concentrations of CSF colistin were higher than the MIC breakpoint throughout the treatment. Meanwhile, no nephrotoxicity or neurotoxicity was observed during the treatment.

Trough polymyxin B plasma concentration is an independent risk factor for its nephrotoxicity.

AIMS: Data regarding clinical pharmacokinetic/toxicodynamic (PK/TD) of polymyxin B is short of direct quantitative data. This study aims to investigate the risk factors of polymyxin B associated acute kidney injury (AKI) and to assess the relationship between polymyxin B plasma levels and its nephrotoxicity. METHODS: A retrospective study was performed in adult patients treated with polymyxin B. Risk factors associated with AKI and plasma trough concentrations of polymyxin B were identified via medical record review. A multivariate logistic regression model was established and the risk of polymyxin B-associated AKI were predicted by a receiver operating characteristic curve, with maximal Youden index used to identify safety thresholds among the study population. RESULTS: Fifty-four adult patients were included in the study. AKI was detected in 14 patients during polymyxin B treatment (25.9%, 14 out of 54). Cmin (odds ratio [OR] 2.071; 95% confidence interval [CI] 1.235-3.472) and baseline serum creatinine (OR 1.024; 95% CI 1.005-1.043) were significant independent risk factors for developing AKI. The area under the ROC curve of the combined predictor was larger based on the above factors. When the Youden index was at maximum, the optimal cut-off point was 6.678 of the ROC curve. When Cmin ≥ 3.13 mg/L, the probability of AKI was more than 50%. CONCLUSION: In this study, when the calculated combined predictor value was >6.678, there was an increased risk of AKI. Maintaining a polymyxin B Cmin level below 3.13 mg/L may be helpful in reducing the incidence of polymyxin B associated nephrotoxicity.

Hepatotoxicity-Related Adverse Effects of Proton Pump Inhibitors: A Cross-Sectional Study of Signal Mining and Analysis of the FDA Adverse Event Report System Database.

Background and Objectives: Mounting evidence demonstrates that proton pump inhibitors (PPIs) are associated with a number of adverse effects. However, the literatures about hepatotoxicity-related adverse effects (HRAEs) of PPIs are mostly case reports and a few clinical studies. Methods: We evaluated the association between PPIs and HAREs using the reporting odd ratio (ROR) for mining the adverse event report signals in the FDA Adverse Event Reporting System (FAERS) database. Results: There were 23,825 reports of PPIs as primary suspect drug or second suspect drug, of which 3,253 reports were HRAEs. The top five HRAE signals caused by PPIs were hepatitis cholestatic, cholestasis, fulminant hepatitis, subacute hepatic failure, and acute hepatitis. We also summarized the signals of the HRAEs caused by each PPI. The simultaneous signals were cholestasis and hepatitis cholestatic. For the cholestasis signal, esomeprazole showed an ROR of 21.556 (95% CI 17.592-26.413); pantoprazole showed the highest ROR of 22.611 (95% CI 17.794-28.733) in the hepatic cholestatic signal; lansoprazole was the only PPI with expression in the coma hepatic signal, with an ROR of 10.424 (95% CI 3.340-32.532). By analyzing the reports of pantoprazole-induced hepatic encephalopathy, we found that patients aged over 65 years and males reported the highest rate. And from the combination of drugs and indications of drugs, no significant results were obtained. Conclusions: The RORs of signals of "cholestasis" were generally higher than those of "hepatocellular injury." And the signals about "cholestasis" in HRAE caused by PPIs are more reported.

Model Based Identification of Linezolid Exposure-toxicity Thresholds in Hospitalized Patients.

Evidence supports linezolid therapeutic drug monitoring as the exposure-response relationship has been identified for toxicity among patients receiving linezolid, but the data to establish the upper limit are limited and the published toxicity thresholds range widely. The purpose of this study was to determine the linezolid exposure-toxicity thresholds to improve the safety of linezolid. This is a multicenter retrospective study of adult patients treated with linezolid from 2018 to 2019. The population pharmacokinetic model of linezolid was established based on 270 plasma concentrations in 152 patients, which showed creatinine clearance and white cell count are covariates affecting the clearance of linezolid, and serum albumin is the covariate affecting the volume of distribution. Classification and regression tree analysis was used to determine the linezolid exposure thresholds associated with an increased probability of toxicity. Among 141 patients included for toxicity analysis, the rate of occurring toxicity was significantly higher among patients with an AUC0-24, d1 ≥163 mg h/L, AUC0-24, d2 ≥207 mg h/L, AUC0-24, ss ≥210 mg h/L, and Cmin,d2 ≥6.9 mg/L, Cmin,ss ≥6.9 mg/L, while no threshold was discovered for Cmin, d1. Those exposure thresholds and duration of linezolid treatment were independently associated with linezolid-related toxicity in the logistic regression analyses. In addition, the predictive performance of the AUC0-24 and Cmin thresholds at day 2 and steady state were close. Considering that the AUC estimation is cumbersome, Cmin threshold at 48 h and steady state with a value of ≥6.9 mg/L is recommended to improve safety, especially for patients with renal insufficiency and patients with low serum albumin.