Piperacillin-tazobactam dosing in anuric acute kidney injury patients receiving continuous renal replacement therapy.

INTRODUCTION: To determine appropriate dosing of piperacillin-tazobactam in critically ill patients receiving continuous renal replacement therapy (CRRT). METHODS: The databases of PubMed, Embase, and ScienceDirect were searched. We used the Medical Subject Headings of "piperacillin-tazobactam," "CRRT," and "pharmacokinetics" or related terms or synonym to identify the studies for reviews. A one-compartment pharmacokinetic model was conducted to predict piperacillin levels for the initial 48 h of therapy. The pharmacodynamic target was 50% of free drug level above the minimum inhibitory concentration (MIC) and 4 times of the MIC. The dose that achieved at least 90% of the probability of target attainment was defined as an optimal dose. RESULTS: Our simulation study reveals that the dosing regimen of piperacillin-tazobactam 12 g/day is appropriate for treating Pseudomonal infection with KDIGO recommended effluent rate of 25-35 mL/kg/h. The MIC values of each setting were an important factor to design piperacillin-tazobactam dosing regimens. CONCLUSION: The Monte Carlo simulation can be a useful tool to evaluate drug dosing in critically ill acute kidney injury patients receiving CRRT when limited pharmacokinetic data are a concern. Clinical validation of these results is needed.

Optimal Meropenem Dosing Regimens in Patients Undergoing Continuous Renal Replacement Therapy: Systematic Review and Monte Carlo Simulations.

INTRODUCTION: The optimal meropenem dosing regimens in critically ill patients receiving continuous renal replacement therapy (CRRT) based on pharmacokinetic and pharmacodynamic (PD) concepts are not well established. This study aimed to (1) gather the available published pharmacokinetic studies conducted in septic patients receiving CRRT and (2) to define the optimal meropenem dosing regimens in these populations via Monte Carlo simulations. METHODS: We used Medical Subject Headings "meropenem," "continuous renal replacement therapy," and "pharmacokinetics" or related terms to identify studies for systematic review. A one-compartment pharmacokinetic model was conducted to predict meropenem levels for the initial 48 h of therapy. The PD targets were 40% of free drug above a threshold of 1 times the minimum inhibitory concentration (MIC) (40% fT > MIC), 4 times the MIC (40% fT > 4MIC), and an additional target of free drug level above 1 times MIC 100% of the time (fT > MIC). The dose that achieved at least 90% of the probability of target attainment (PTA) was defined as an optimal dose. RESULTS: Twenty-one articles were included for our systematic review. The necessary pharmacokinetic parameters such as volume of distribution and CRRT clearance were cited in 90.5 and 71.4% of articles, respectively. None of the published studies reported completed necessary parameters. A regimen of 750 mg q 8 h was found to be the optimal dose for pre-dilution continuous venovenous hemofiltration and continuous venovenous hemodialysis modality using two effluent rates (25 and 35 mL/kg/h) which achieved the PD target of 40% fT > 4MIC. CONCLUSION: None of the published studies showed the necessary pharmacokinetic parameters. PD target significantly contributed to meropenem dosage regimens in these patients. Differing effluent rates and types of CRRT shared similar dosing regimens. Clinical validation of the recommendation is suggested.

Population Pharmacokinetics/Pharmacodynamics and Clinical Outcomes of Meropenem in Critically Ill Patients.

Several pathophysiological changes can alter meropenem pharmacokinetics in critically ill patients, thereby increasing the risk of subtherapeutic concentrations and affecting therapeutic outcomes. This study aimed to characterize the population pharmacokinetic (PPK) parameters of meropenem, evaluate the relationship between the pharmacokinetic/pharmacodynamic index of meropenem and treatment outcomes, and evaluate the different dosage regimens that can achieve 40%, 75%, and 100% of the dosing interval for which the free plasma concentrations remain above the MIC of the pathogens (fT>MIC) targets. Critically ill adult patients treated with meropenem were recruited for this study. Five blood samples were collected from each patient. PPK models were developed using a nonlinear mixed-effects modeling approach, and the final model was subsequently used for Monte Carlo simulations to determine the optimal dosage regimens. A total of 247 concentrations from 52 patients were available for analysis. The two-compartment model with linear elimination adequately described the data. The mean PPK parameters were clearance (CL) of 4.8 L/h, central volume of distribution (VC) of 11.4 L, peripheral volume of distribution (VP) of 14.6 L, and intercompartment clearance of 10.5 L/h. Creatinine clearance was a significant covariate affecting CL, while serum albumin level and shock status were factors influencing VC and VP, respectively. Although 75% of the drug-resistant infection patients had fT>MIC values of >40%, approximately 83% of them did not survive the infection. Therefore, 40% fT>MIC might not be sufficient for critically ill patients, and a higher target, such as 75 to 100% fT>MIC, should be considered for optimizing therapy. A 75% fT>MIC could be reached using approved doses administered via a 3-h infusion.

Levetiracetam dosing in patients receiving continuous renal replacement therapy.

OBJECTIVE: The study was aimed to define appropriate levetiracetam dosing regimens from available published pharmacokinetics (PK) studies in critically ill patients with and without cirrhosis receiving continuous renal replacement therapy (CRRT) via Monte Carlo simulation (MCS). METHODS: Mathematical pharmacokinetic models were developed using published demographic and PK data in adult critically ill patients with known variability and correlations between PK parameters. CRRT modalities (continuous venovenous hemofiltration and continuous venovenous hemodialysis) with different effluent rates were modeled. Levetiracetam regimens from available clinical resources were evaluated on the probability of target attainment (PTA) using pharmacodynamics (PD) target of the trough concentrations and area under the time-concentration curve within a range of 6-20 mg/L and 222-666 mg × hour/L for the initial 72 hours of therapy, respectively. Optimal regimens were defined from regimens that yielded the highest PTA. Each regimen was tested in a group of different 10,000 virtual patients. RESULTS: Our results showed the optimal levetiracetam dosing regimen of 750-1000 mg every 12 hours is recommended for adult patients receiving both CRRT modalities with two different effluent rates of 25 and 35 mL/kg/h. Child-Pugh class C cirrhotic patients undergoing CRRT required lower dosing regimens of 500-750 mg every 12 ours due to smaller non-renal clearance. Of interest, some of literature-based dosing regimens were not able to attain the PK and PD targets. SIGNIFICANCE: Volume of distribution, non-renal clearance, CRRT clearance, and body weight were significantly correlated with the PTA targets. Dosing adaptation in this vulnerable population should be concerned. Clinical validation of our finding is absolutely needed.

Vancomycin Dosing Regimen by Monte Carlo Simulation in Patients on Intermittent High-Efficiency Hemodialysis (HEHD).

OBJECTIVE: To evaluate the effective vancomycin dosing regimens by Monte Carlo simulation among patients on intermittent high-efficiency hemodialysis (HEHD). MATERIAL AND METHOD: The present study was conducted on eight end-stage renal disease patients receiving HEHD. The patients received an initial dose of vancomycin 1 g followedby 500 mg immediately after HEHD session for a supplementation. Blood samplings were obtained to investigate vancomycin pharmacokinetic parameters. A Monte Carlo simulation was performed to determine the percentage of probability of target attainment (PTA) achieving AUC24/MIC ratio greater than or equal to 400 as the target of achievement of antimicrobial activity. RESULTS: A loading dose (LD) of vancomycin of 20 mg per kilogram of dry weight (DW) with or without a supplementation had the optimum effectiveness for pathogens with MICs not greater than 0.5 mg/L. For pathogens with an MIC of 1.0 mg/L, the LD of 25 mg/kgDW followed by 20 or 25 mg/kgDW supplementation was achieved the target in some cases. Therefore, the LD of 30 mg/kgDW followed by 25 mg/kgDW or the LD of 35 mg/kgDW with 10, 20 or 25 mg/kgDW supplementation was required to achieve the target of antimicrobial activity. CONCLUSION: From the present study, the lowest vancomycin dosing regimen that had the optimum effectiveness was a 35 mg/kgDW LD followed by 10 mg/kgDW supplementation. This regimen is recommended to treat pathogens with MICs not greater than 1.0 mg/L.

Single dosage of doxycycline for prophylaxis against leptospiral infection and leptospirosis during urban flooding in southern Thailand: a non-randomized controlled trial.

This study was conducted to investigate the protective efficacy of a single dosage of 200 mg doxycycline against leptospiral infection and leptospirosis and associated risk factors among residents exposed to flooding in southern Thailand. Of 641 participants, 600 received doxycycline while 41 did not. Twenty two participants were infected with Leptospira and six developed leptospirosis. Having a laceration wound was significantly associated with leptospiral infection (odds ratio [OR] = 37.20; P < 0.001) and leptospirosis (OR = 18.24; P = 0.003) whereas exposure to flood more than 3 h per day was associated with only leptospiral infection (OR = 3.70; P = 0.038). Seventeen participants who received doxycycline and five who did not, were infected with Leptospira, resulting a protective efficacy of 76.8% (95% confidence interval [CI] = 34.3%-92.0%). Four who received doxycycline and two who did not, developed leptospirosis, resulting a protective efficacy of 86.3% (CI = -9.8%-98.2%). Among the participants with laceration wound, the protective efficacy for leptospiral infection was 92.0% (CI = 81.2%-96.6%) and for leptospirosis was 95.6% (CI = 78.2%-99.3%). Among the participants exposed to flood water less than or equal to 3 h per day, the protective efficacy for leptospiral infection was 89.2% (95% CI 63.6%-96.67%). A single dosage of 200 mg doxycycline for prophylaxis might be effective for preventing leptospirosis among flood victims with laceration wound after recent flood exposure.

Initial dosage regimen of vancomycin for septic shock patients: a pharmacokinetic study and Monte Carlo simulation.

OBJECTIVE: To evaluate the pharmacokinetic parameters of vancomycin in septic shock patients and to determine the vancomycin dosage to achieve requisite pharmacokinetic/pharmacodynamic (PK/PD) target against methicillin resistant Staphylocccus aureus (MRSA) in patients with septic shock. MATERIAL AND METHOD: Pharmacokinetic parameters of vancomycin in 12 septic shock patients were assessed. Then, the Monte Carlo simulation was performed to calculate the probabilities of target attainment (PTAs) to reach target AUC0-24/MIC of 400 and 450 mg.h/L. RESULTS: The total clearance (CL) and the volume of the central compartment (Vc) of vancomycin was 3.34±1.39 L/h and 0.14±1.43 L/kg, respectively. For Staphylococcalspp. with low MICs of 0.125 and 0.5 mg/L, the administration of vancomycin 30 mg/kg as the loading dose, followed by the maintenance dose of 20 mg/kg every six, eight, 12, and 24 hours achieved >90% PTAs to reach target AUC0-24/MlC: For pathogens with MIC of 1, and 1.5 mg/L, the vancomycin maintenance dose of 20 mg/kg every six, eight, and 12 hours and every six and eight hours respectively to achieve >90% PTA. CONCLUSION: High dose ofvancomycin is required to achieve PK/PD target for treatment of MRSA septic shock, especially if MRSA MIC is higher than 1 mg/L.

Pharmacokinetics of intravenous piperacillin/tazobactam among patients with peritoneal dialysis-associated peritonitis.

Currently, pharmacokinetic information on intravenous (IV) piperacillin/tazobactam in patients with peritoneal dialysis-associated peritonitis (PD peritonitis) is limited. This study employed a prospective single-dose pharmacokinetic design to assess the pharmacokinetics of IV piperacillin/tazobactam in these patients. Four patients with PD peritonitis who received an IV loading dose of 4000 mg/500 mg piperacillin/tazobactam were enrolled in this study. The concentrations of piperacillin and tazobactam in plasma, peritoneal dialysis fluid (PDF) and urine were determined by high-performance liquid chromatography. Non-compartmental methods were used for pharmacokinetic analysis. During a 6-h dwell time for chronic ambulatory peritoneal dialysis (CAPD), 9.23 ± 4.01% of the piperacillin was recovered in the PDF. This result is greater than that observed in patients without peritonitis in prior research. Piperacillin's PD clearance (CLPD), steady-state volume of distribution (Vss) and terminal half-life (t 1/2) were 5.79 ± 2.55 mL/min, 24.35 ± 11.26 L and 5.74 ± 1.53 h, respectively. These values are also higher than those of patients without peritonitis in a prior study. Eight hours following the loading dosage, the plasma and PDF piperacillin concentrations of all patients (98.25 ± 26.03 and 52.70 ± 22.99 mg/L, respectively) surpassed the Pseudomonas aeruginosa and Enterobacterales Clinical and Laboratory Standards Institute susceptible breakpoints. In summary, the CLPD, Vss and t 1/2 for piperacillin were found to be greater in patients with PD peritonitis than in CAPD patients without peritonitis when compared with the results of a previous study. The IV loading dose of 4000 mg/500 mg piperacillin/tazobactam is sufficient to treat peritonitis caused by susceptible P. aeruginosa and Enterobacterales. The multiple-dose pharmacokinetics of IV piperacillin and tazobactam in this specific patient group should be further investigated.

Lacosamide dosing in patients receiving continuous renal replacement therapy.

BACKGROUND: Lacosamide is one of the anticonvulsants used in critically ill patients. This study aimed to suggest appropriate lacosamide dosing regimens in critically ill patients receiving continuous renal replacement therapy (CRRT) via Monte Carlo simulations. METHODS: Mathematical models were created using published demographic and pharmacokinetics in adult critically ill patients. CRRT modalities with different effluent rates were added into the models. Lacosamide regimens were evaluated on the probability of target attainment (PTA) using pharmacodynamic targets of trough concentrations and area under the curve within a range of 5-10 mg/L and 80.25-143 and 143-231 mg*h/L for the initial 72 h-therapy, respectively. Optimal regimens were defined from regimens that yielded the highest PTA. Each dosing regimen was tested in a group of different 10,000 virtual patients. RESULTS: Our results revealed the optimal lacosamide dosing regimen of 300-450 mg/day is recommended for adult patients receiving both CRRT modalities with 20-25 effluent rates. The dose of 600 mg/day was suggested in higher effluent rate of 35 mL/kg/h. Moreover, a patient with body weight > 100 kg was less likely to attain the targets. CONCLUSIONS: Volume of distribution, total clearance, CRRT clearance and body weight were significantly contributed to lacosamide dosing. Clinical validation of the finding is strongly indicated.

Case report of clindamycin graded challenge in an AIDS patient allergic to clindamycin.

The aim of this study was to report the success of a clindamycin graded challenge. The patient was a 39-year-old human immunodeficiency virus-infected male with toxoplasmic encephalitis (TE) with a history of trimethoprim/sulfamethoxazole (TMP/SMX) and clindamycin allergy. He developed a reaction during TMP/SMX desensitization. Following the reaction, a graded challenge with clindamycin was performed in this study, and he became tolerant to clindamycin. No adverse drug reactions developed during the graded challenge. He successfully continued suppressive therapy with no further reactions or recurrences.

Comparison of Race-Based and Non-Race-Based Equations for Kidney Function Estimation in Critically Ill Thai Patients for Vancomycin Dosing.

Empiric antibiotic dosing frequently relies on an estimate of kidney function based on age, serum creatinine, sex, and race (on occasion). New non-race-based estimated glomerular filtration rate (eGFR) equations have been published, but their role in supporting dosing is not known. Here, we report on a population pharmacokinetic model of vancomycin that serves as a useful probe substrate of eGFR in critically ill Thai patients. Data were obtained from medical records during a 10-year period. A nonlinear mixed-effects modeling approach was conducted to estimate vancomycin parameters. Data from 208 critically ill patients (58.2% men and 36.0% septic shock) with 398 vancomycin concentrations were collected. Twenty-three covariates including 12 kidney function estimates were tested and ranked on the basis of the model performance. The median (min, max) age, weight, and serum creatinine was 69 (18, 97) years, 60.0 (27, 120) kg, and 1.53 (0.18, 7.15) mg/dL, respectively. The best base model was a 1-compartment linear elimination with zero-order input and proportional error model. A Thai-specific eGFR equation not indexed to body surface area model best predicted vancomycin clearance (CL). The typical value for volume of distribution and CL was 67.5 L and 1.22 L/h, respectively. A loading dose of 2000 mg followed by maintenance dose regimens based on eGFR is suggested. The Thai GFR not indexed to BSA model best predicts vancomycin CL and dosing in the critically ill Thai population. A 5% to 10% absolute gain in the vancomycin probability of target attainment is expected with the use of this population-specific eGFR equation.

Patient, Disease, and Drug-Related Risk Factors Associated with Phenytoin- Induced Cutaneous Adverse Drug Reactions in South Indian Epileptic Patients - A Prospective Case-Control Study.

BACKGROUND: Phenytoin is the most commonly reported aromatic Anti-Epileptic Drug (AED) to cause Cutaneous Adverse Drug Reactions (CADRs). Cutaneous adverse drug reactions may be immune or non-immune mediated. It has been observed that predisposition is multifactorial and that gene mutations alone cannot be the cause. OBJECTIVES: In this study, we investigated the patient, disease, and drug-related risk factors associated with phenytoin-induced cutaneous adverse drug reactions in South Indian epileptic patients. METHODS: This study was conducted as a single-center prospective case-control study over a period of 13 months. The Fisher's exact test and multivariate binary logistic regression analysis were used to test the association of single and multiple variables, respectively. RESULTS: This study comprised 26 patients with phenytoin-induced cutaneous adverse drug reactions (PHT-CARDs) and 32 phenytoin-tolerant controls with a mean age of 40.60±18.15 and 36.21±14.71 years, respectively. Among 26 phenytoin-induced cutaneous adverse drug reactions, 76.92% cases were mild-moderate reactions and 23.07% were severe. The onset latency period of these reactions ranged from 7-42 days. The multivariate analysis showed that multiple AEDs (OR =18.62, 95% CI 4.28-80.87, p=< .001) and comorbidities (OR= 5.98, 95% CI 1.33-26.78, p=.01) are risk factors for PHT-CADRs. PHT-SCARs were shown to be associated with previous allergy history (OR= 31, % CI 2.40-398.8, p=.008). CONCLUSION: The risk factors found to be associated with CARDs in South Indian Epileptic patients are multiple AEDs, comorbidities, and past allergic history. Therefore, physicians and other associated health care professionals should closely monitor the patients when phenytoin is employed.

Association Between Types of Carbapenemase and Clinical Outcomes of Infection Due to Carbapenem Resistance Enterobacterales.

Purpose: Compared with non-carbapenemase producing carbapenem-resistant Enterobacterales (non-CP-CRE), carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) are associated with considerable mortality. However, given that the patients are treated with various therapeutic options, it remains unclear whether differences in types of carbapenemase genes yield different mortality rates. Therefore, this study aims to identify carbapenemase genes and identify whether clinical outcomes differ according to the prevalence of genotype and phenotype of carbapenemase among Enterobacterales clinical isolated. Patients and Methods: A retrospective cohort study was performed to determine whether types of carbapenemase genes have an impact on clinical outcomes. Carbapenem-resistant clinical isolates were collected at a tertiary care university hospital in Songkhla, Thailand, between June 2018 and February 2020. Demographic and microbiological data such as antimicrobial susceptibility, carbapenemase genes, and overall mortality were evaluated. Results: A total of 121 Enterobacterales clinical isolated were evaluated. The bla NDM-1 gene was detected in 44% of the isolates, followed by bla OXA-48 (28%) and bla NDM-1/OXA-48 (28%). NDM-1- or NDM-1/OXA-48- producing isolates were more likely to require meropenem MICs of ≥16 mg/L, while OXA-48-producing isolates were more likely to require meropenem MICs of <16 mg/L. The patients with NDM-1 or NDM-1/OXA-48 had a higher 14 days mortality rate than those with OXA-48 after treating with carbapenem-containing regimens (P-value 0.001) or colistin-containing regimens (P-value < 0.001). Conclusion: Our findings suggest that the mortality for CP-CRE infection in patients with NDM-1 or NDM-1/OXA-48 was higher than the mortality in those with OXA-48, which It seems that the type of carbapenemase gene may affect meropenem MIC levels. Hence, in treatment decisions involving the use of either carbapenem-containing regiment or colistin-containing regiment in patients with CP-CRE infection, especially those in the NDM-1 and NDM-1/OXA-48 groups, the patient symptoms should be closely monitored.

In vitro activity of colistin or sulbactam in combination with fosfomycin or imipenem against clinical isolates of carbapenem-resistant Acinetobacter baumannii producing OXA-23 carbapenemases.

This study investigated the in vitro activity of colistin or sulbactam in combination with fosfomycin or imipenem against eight strains of carbapenem-resistant A. baumannii (CRAB). The eight CRAB clinical isolates were collected from hospitalized patients admitted to Songklanagarind Hospital in southern Thailand during January-December 2008. The isolates were divided into 4 different patterns of clonal relationships using the Repetitive Extragenic Palindromic-Polymerase Chain Reaction method (REP-PCR). The in vitro activity of combination antibacterial agents against theses isolates were determined by chequerboard and time-kill methods. All isolates producing OXA-23 carbapenemases were universally susceptible to colistin but intermittently susceptible to other antimicrobial agents. A chequerboard assay showed the synergistic effects of sulbactam plus fosfomycin and colistin plus fosfomycin in 75% and 12.5% of isolates, respectively. Sulbactam at a concentration of 1 x MIC plus fosfomycin at 1 x MIC or at 1/4 x MIC showed synergism in 75% and 37.5% of clinical isolates, respectively. Bactericidal activity was observed for up to 12 hours of incubation. There was no synergism between colistin and sulbactam, sulbactam and imipenem, and colistin and imipenem, against the tested isolates. Combined use of sulbactam and fosfomycin may provide an alternative therapeutic option for CRAB infections.

Clinical outcomes of patients infected with carbapenem-resistant Acinetobacter baumannii treated with single or combination antibiotic therapy.

OBJECTIVE: To evaluate treatment outcomes in patients with carbapenem-resistant Acinetobacter baumannii (CRAB) nosocomial infections treated with antimicrobial agent either alone or in combination. MATERIAL AND METHOD: Clinical data were retrospectively evaluated in patients with CRAB nosocomial infections admitted to Songklanagarind Hospital, Songkhla, Thailand from January-December 2008. RESULTS: One hundred ten patients with CRAB nosocomial infections were identified. Most patients (57.3%) had site of infection in the lower respiratory tract and the majority of them (61.8%) received a single antimicrobial agent. Crude mortality was 30%. The presumptive success rate was 60.3% (41/68) for patients given monotherapy and 81.0% (34/42) for patients given combination therapy (p = 0.024). Patients given combination therapy were more likely to have been given at least one antibiotic to which the organism was susceptible (p = 0.004). In multivariate analysis, renal impairment, bloodstream infection, and inappropriate antimicrobial regimen were independent predictors of treatment failure. CONCLUSION: The combination therapy regimen yielded more presumptive treatment success by increasing the likelihood of an appropriate antimicrobial therapy. Additionally, inappropriate antimicrobial treatment, renal impairment, and bloodstream infection were associated with poor treatment outcomes in patients with CRAB nosocomial infections.

Efficacy and Safety of Enteral Erythromycin Estolate in Combination With Intravenous Metoclopramide vs Intravenous Metoclopramide Monotherapy in Mechanically Ventilated Patients With Enteral Feeding Intolerance: A Randomized, Double-Blind, Controlled Pilot Study.

BACKGROUND: In this pilot study, we aimed to determine the efficacy and safety of enteral erythromycin estolate in combination with intravenous metoclopramide compared to intravenous metoclopramide monotherapy in mechanically ventilated patients with enteral feeding intolerance. METHODS: This randomized, double-blind, controlled pilot study included 35 mechanically ventilated patients with feeding intolerance who were randomly assigned to receive 10-mg metoclopramide intravenously every 6-8 hours in combination with 250-mg enteral erythromycin estolate (study group) or placebo every 6 hours for 7 days. The primary outcome was an administered-to-target energy ratio of ≥80% at 48 hours, indicating a successful feeding. Secondary, prespecified outcomes were daily average gastric residual volume (GRV), total energy intake, administered-to-target energy ratio, hospital length of stay, in-hospital mortality, and 28-day mortality. RESULTS: The rate of successful feeding was not significantly different between the study and placebo groups (47.1% and 61.1%, respectively; P = .51). The average daily GRV was significantly lower in the study group than in the placebo group (ß = 91.58 [95% Wald CI, -164.35 to -18.8]), determined by generalized estimating equation. Other secondary outcomes were comparable, and the incidence of adverse events was not significantly different between the 2 groups. One common complication was cardiac arrhythmia, which was mostly self-terminated. CONCLUSION: Although the combination therapy of enteral erythromycin estolate and intravenous metoclopramide reduced GRV, the successful feeding rate and other patient-specific outcomes did not improve in mechanically ventilated patients with feeding intolerance.

Association of HLA-B*51:01, HLA-B*55:01, CYP2C9*3, and Phenytoin-Induced Cutaneous Adverse Drug Reactions in the South Indian Tamil Population.

Phenytoin (PHT) is one of the most commonly reported aromatic anti-epileptic drugs (AEDs) to cause cutaneous adverse reactions (CADRs), particularly severe cutaneous adverse reactions (SCARs). Although human leukocyte antigen (HLA)-B*15:02 is associated with PHT-induced Steven Johnson syndrome/toxic epidermal necrosis (SJS/TEN) in East Asians, the association is much weaker than it is reported for carbamazepine (CBZ). In this study, we investigated the association of pharmacogenetic variants of the HLA B gene and CYP2C9*3 with PHT-CADRs in South Indian epileptic patients. This prospective case-controlled study included 25 PHT-induced CADRs, 30 phenytoin-tolerant patients, and 463 (HLA-B) and 82 (CYP2C9*3) normal-controls from previous studies included for the case and normal-control comparison. Six SCARs cases and 19 mild-moderate reactions were observed among the 25 cases. Pooled data analysis was performed for the HLA B*51:01 and PHT-CADRs associations. The Fisher exact test and multivariate binary logistic regression analysis were used to identify the susceptible alleles associated with PHT-CADRs. Multivariate analysis showed that CYP2C9*3 was significantly associated with overall PHT-CADRs (OR = 12.00, 95% CI 2.759-84.87, p = 003). In subgroup analysis, CYP2C9*3 and HLA B*55:01 were found to be associated with PHT-SCARs (OR = 12.45, 95% CI 1.138-136.2, p = 0.003) and PHT-maculopapular exanthema (MPE) (OR = 4.041, 95% CI 1.125-15.67, p = 0.035), respectively. Pooled data analysis has confirmed the association between HLA B*51:01/PHT-SCARs (OR = 6.273, 95% CI 2.24-16.69, p = <0.001) and HLA B*51:01/PHT-overall CADRs (OR = 2.323, 95% CI 1.22-5.899, p = 0.037). In this study, neither the case nor the control groups had any patients with HLA B*15:02. The risk variables for PHT-SCARs, PHT-overall CADRs, and PHT-MPE were found to be HLA B*51:01, CYP2C9*3, and HLA B*55:01, respectively. These alleles were identified as the risk factors for the first time in the South Indian Tamil population for PHT-CADRs. Further investigation is warranted to establish the clinical relevance of these alleles in this population with larger sample size.

Optimal levofloxacin dosing regimens in critically ill patients with acute kidney injury receiving continuous renal replacement therapy.

PURPOSES: To determine appropriate dosing of levofloxacin in critically ill patients receiving continuous renal replacement therapy (CRRT). METHODS: All necessary pharmacokinetic and pharmacodynamic parameters from critically ill patients were obtained to develop mathematical models with first order elimination. Levofloxacin concentration-time profiles were calculated to determine the efficacy based on the probability of target attainment (PTA) of AUC24h/MIC ≥50 for Gram-positive and AUC24h/MIC ≥125 for Gram-negative infections. A group of 5000 virtual patients was simulated and tested using Monte Carlo simulations for each dose in the models. The optimal dosing regimens were defined as the dose achieved target PTA at least 90% of the virtual patients. RESULTS: No conventional, FDA approved regimens achieved at least 90% of PTA for Gram-negative infection with Pseudomonas aeruginosa at MIC of 2 mg/L. The successful dose (1750 mg on day 1, then 1500 mg q 24 h) was far exceeded the maximum FDA-approved doses. For Gram-positive infections, a levofloxacin 750 mg q 24 h was sufficient to attain PTA target of ~90% at the MIC of 2 mg/L for Streptococcus pneumoniae. CONCLUSIONS: Levofloxacin cannot be recommended as an empiric monotherapy for serious Gram-negative infections in patients receiving CRRT due to suboptimal efficacy.

Incidence and Risk Factors for Venous Thromboembolism Following Craniotomy for Intracranial Tumors: A Cohort Study.

CONTEXT: Venous thromboembolism (VTE) is a devastating complication of intracranial tumor surgery. The present study helps identify patients at the greatest risk of developing VTE. AIMS: The aim of the study was to evaluate the incidence of and risk factors for VTE following craniotomy for intracranial tumors. SETTING AND DESIGNS: This was a retrospective cohort study. METHODS: Data from the institutional database (between January 2017 and December 2018) were reviewed. Consecutive patients with intracranial tumors who underwent craniotomy were included. STATISTICAL ANALYSIS USED: Patient characteristics were reported as descriptive data, and factors associated with VTE development were analyzed by the Cox regression model. RESULTS: The study identified 177 patients. The incidence of VTE was 10.2% (deep-vein thrombosis [DVT], 8.5%; pulmonary embolism [PE] 1.7%; and simultaneous DVT and PE, 1.7%). In univariate analysis, VTE development was associated with diabetes mellitus (DM), operative duration of >420 min, blood transfusion, and new-onset postoperative motor deficits. DM and new-onset postoperative motor deficits were statistically significant factors in multivariable analysis, with hazard ratios of 4.52 (95% confidence interval [CI] = 1.38-14.82) and 3.46 (95% CI = 1.17-10.23), respectively. CONCLUSIONS: Postcraniotomy VTE was detected in 10.2% of patients with intracranial tumors. Risk factors for VTE included DM and new-onset postoperative motor deficits. Hence, intracranial tumor patients with these risk factors are the most likely to require VTE prophylaxis with an anticoagulant.

Postoperative Venous Thromboembolism in Extramedullary Spinal Tumors.

CONTEXT: Venous thromboembolism (VTE), including deep-vein thrombosis (DVT) and pulmonary embolism (PE), is the fatal complication following spine surgery and the appropriate perioperative prophylaxis is still debated. AIMS: The aim of this study is to evaluate the incidence of along with risk factors for postoperative VTE in surgically treated extramedullary spinal tumor patients. SETTING AND DESIGNS: The study design involves single institute and retrospective cohort study. SUBJECTS AND METHODS: The cohort database was reviewed between the periods of January 2014 and June 2019. Patients undergoing surgery for spine tumor, extradural tumor, and intradural extramedullary were consecutively collected. STATISTICAL ANALYSIS USED: The incidence of VTE and clinical factors reported to be associated with VTE were identified, and then analyzed with an appropriate Cox regression model. RESULTS: The study identified 103 extramedullary spinal tumor patients. Three patients (2.9%) were diagnosed with a proximal leg DVT, while symptomatic PE did not identify. Risk factors associated with DVT occurrence were as follows: operative time ≥8 h (Hazard ratio [HR] 13.98, P = 0.03) and plasma transfusion (HR 16.38, P = 0.02), whereas plasma transfusion was the only significant factor, after multivariate analysis (HR 11.77, P = 0.05). CONCLUSIONS: Patients who underwent surgery for extramedullary spinal tumors showed a 2.9% incidence of DVT. The highest rate of DVT was found in patients who received plasma transfusion. More attention should be paid on perioperative associated factors for intensive prevention coupled with early screening in this group.