Desired vancomycin trough concentration to achieve an AUC0‐24/MIC ≥400 in Chinese children with complicated infectious diseases

A vancomycin steady‐state trough concentration (C_min) of 15‐20 mg/L is recommended for achieving a ratio of the 24‐hour area under the curve to the minimum inhibitory concentration (AUC_0‐24/MIC) of ≥400 in adults. Since few paediatric data are available, our objectives were to (a) measure the pharmacokinetic indices of vancomycin and (b) determine the correlation between C_min and AUC_0‐24/MIC in paediatric patients. Population‐based pharmacokinetic modelling was performed for paediatric patients to estimate the individual parameters. The relationship between C_min and the calculated AUC_0‐24/MIC was explored using linear regression and a probabilistic framework. A sensitivity analysis was also conducted using Monte Carlo simulations. Body‐weight significantly influenced the pharmacokinetics of vancomycin. Based on real data and simulations, C_min ranges of 5.0‐5.9 and 9.0‐12.9 mg/L were associated with AUC_0‐24/MIC ≥400 for MIC values of ≤0.5 and ≤1 mg/L, respectively. Vancomycin regimens of 10 and 15 mg/kg every 6 hours achieved a C_min of 5.0‐5.9 mg/L and AUC_0‐24/MIC ≥400 in >90% of the children when MIC was ≤0.5 mg/L. At a MIC of ≤1 mg/L, vancomycin at 15 mg/kg every 6 hours achieved C_min of 9.0‐12.9 mg/L and AUC_0‐24/MIC ≥400 in 2.0‐ and 1.6‐fold as many children compared to a dose of 10 mg/kg every 6 hours, respectively. Vancomycin C_min values of 5.0‐12.9 mg/L were strongly predictive of achieving AUC_0‐24/MIC ≥400, and rational dosing regimens of 10‐15 mg/kg q6h were required in paediatric patients, depending on the pathogen.     

Pharmacokinetics and Toxicity of Tacrolimus Early After Heart and Lung Transplantation

Annually, about 8000 heart and lung transplantations are successfully performed worldwide. However, morbidity and mortality still pose a major concern. Renal failure in heart and lung transplant recipients is an essential adverse cause of morbidity and mortality, often originating in the early postoperative phase. At this time of clinical instability, the kidneys are exposed to numerous nephrotoxic stimuli. Among these, tacrolimus toxicity plays an important role, and its pharmacokinetics may be significantly altered in this critical phase by fluctuating drug absorption, changed protein metabolism, anemia and (multi‐) organ failure. Limited understanding of tacrolimus pharmacokinetics in these circumstances is hampering daily practice. Tacrolimus dose adjustments are generally based on whole blood trough levels, which widely vary early after transplantation. Moreover, whole blood trough levels are difficult to predict and are poorly related to the area under the concentration‐time curve. Even within the therapeutic range, toxicity may occur. These shortcomings of tacrolimus monitoring may not hold for the unbound tacrolimus plasma concentrations, which may better reflect tacrolimus toxicity. This review focuses on posttransplant tacrolimus pharmacokinetics, discusses relevant factors influencing the unbound tacrolimus concentrations and tacrolimus (nephro‐) toxicity in heart and lung transplantation patients.     

不同抗病毒药物对带状疱疹的药效经济学研究

目的 探究带状疱疹患者使用阿昔洛韦、伐昔洛韦和利巴韦林等三种不同抗病毒药物实际应用中成本-疗效分析,为临床用药提供指导意义.方法 选取自2009年3月到2014年5月来我院就治并确诊为带状疱疹患者126例,采用随机抽样分为三组,其中A组采用阿昔洛韦抗疱疹病毒药物治疗,B组采用伐昔洛韦抗疱疹病毒药物治疗,C组采用利巴韦林广谱抗病毒药物治疗,观察分析三组患者临床有效率和治疗成本状况并计算成本/效果比.结果 治疗结束后,三组(A、B、C)患者治疗成本费分别为594.23±96.75元、721.77±101.32元、518.46±89.16元,相互之间存在显著统计学差异(t =6.003,3.729,9.509,P＜0.01).治疗效果方面,A组有效率(84.78％)和B组有效率(92.68％)远远超过C组有效率(71.79％),但A、B两组间不存在差异(x2=1.330,P＞0.05).住院时间上,A组患者要高于B组(t=2.254,P＜0.05),成本-效果比方面,A组(696.06)小于B组(772.11).结论 衡量治疗成本和疗效,从长远看,阿昔洛韦可以作为治疗首选药物,近期快速控制方面,伐昔洛韦可以作为首选药物.     

Soluble form of FGFR2 with S252W partially prevents craniosynostosis of the apert mouse model

Background: Apert syndrome (AS) is characterized by craniosynostosis, midfacial hypoplasia, and bony syndactyly. It is an autosomal dominantly inherited disease caused by point mutations (S252W or P253R) in fibroblast growth factor receptor (FGFR) 2. These mutations cause activation of FGFR2 depending on ligand binding. Recently, an AS mouse model, Fgfr2^+/S252W, showed phenotypes similar to those of AS patients. We previously reported that the soluble form of FGFR2^S252W (sFGFR2IIIc^S252W) efficiently inhibits enhanced osteoblastic differentiation caused by FGFR2 activation in AS in vitro, presumably because FGFs binding to FGFRs is interrupted. In this study, we developed Fgfr2^+/S252W (Ap) mice expressing the sFGFR2IIIc^S252W protein, and we investigated the effects of sFGFR2IIIc^S252W on AS‐like phenotypes. Results: In Ap mice, the coronal suture (CS) was fused prematurely at P1. In addition, the mice exhibited a widened interfrontal suture (IFS) with ectopic bone and thickened cartilage formation. In Fgfr2^+/S252W sFGFR2IIIc^S252W (Ap/Sol) mice, the CS was similar to that of wild‐type mice. Ap/Sol mice did not show any ectopic bone or cartilage formation in the IFS, but showed a wider IFS than that of the wild‐type mice. Conclusions: sFGFR2IIIc^S252W may partially prevent craniosynostosis in the Apert mouse model by affecting the CS and IFS in vivo. Developmental Dynamics 243:560–567, 2014. © 2013 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.     

Application of PK/PD Modeling and Simulation to Dosing Regimen Optimization of High-Dose Human Regular U-500 Insulin

Background:Pharmacokinetic/pharmacodynamic (PK/PD) studies of human regular U-500 insulin (U-500R) at high doses commonly used in clinical practice (>100 units) have not been performed. The current analysis applied PK/PD modeling/simulation to fit the data and simulate single-dose and steady-state PK/PD of U-500R high-dose regimens.Method:Data from 3 single-dose euglycemic clamp studies in healthy obese and normal-weight patients, and normal-weight patients with type 1 diabetes were used to build the model. The model was sequential (PK inputs fed into PD component). PK was described using a 1-compartment model with first-order absorption and elimination. The model estimated separate absorption rate constants for U-500R and human regular U-100 insulin. The PD component used an effect compartment model, parameterized in terms of maximum pharmacologic effect (E_max) and concentration to achieve 50% of E_max.Results:The model described the data well. Steady-state PK for once-daily (QD), twice-daily (BID), or thrice-daily (TID) administration appeared to be reached 24 hours after the first dose. At steady-state, QD dosing showed the greatest fluctuations in PK/PD. BID dosing showed a gradual increase in insulin action with each dose and a fairly stable basal insulin effect. For TID dosing, activity was maintained throughout the dosing interval.Conclusions:PK/PD modeling/simulation of high U-500R doses supports BID or TID administration with an extended duration of activity relative to QD. TID dosing may provide slightly better full-day insulin effect. Additional PK/PD studies and randomized controlled trials of U-500R are needed to validate model predictions in patients with insulin-resistant diabetes requiring high-dose insulin.     

姜炭在虚寒性出血证大鼠体内的整合药代动力学与温经止血药效学的相关性研究

目的:探讨姜炭在虚寒性出血证大鼠体内的整合药代动力学与温经止血药效学之间的相关性。方法:18只雄性SD大鼠随机分为空白组、模型组和姜炭组,每组6只。模型组和姜炭组大鼠诱导虚寒性出血证模型。造模同时,姜炭组大鼠灌胃给予0.007 g/kg姜炭乙酸乙酯提取液,空白组和模型组大鼠灌胃给予等体积蒸馏水,连续5 d。末次给药后分别于0.083、0.25、0.5、0.75、1、2、3、4、6、8、10、12 h采集血样。高效液相色谱(HPLC)法测定各组大鼠不同时间点血清中6-姜烯酮、6-姜烯酚、姜酮、二乙酰基-6-姜酚、6-姜酚、10-姜酚的含量。基于自定义权重系数法建立整合药代动力学模型,并计算整合药动学参数。酶联免疫吸附法(ELISA)检测血清血栓素B_2(TXB_2)和6-酮-前列腺素F_(1α)(6-keto-PGF_(lα))的含量,并计算药效强度。对整合血药浓度与药效强度进行相关性分析。结果:①建立整合药代动力学模型,计算药动学参数半衰期(t_(1/2))为(3.59±0.20)h,达峰时间(T_(max))为(3.00±0.00)h,最大浓度(C_(max))为(6.34±0.24)μg/ml,曲线下面积(AUC_(0-∞))为(44.44±1.41)μg·h/ml,平均滞留时间(MRT)为(5.85±0.18)h,表观清除率(CL/F)为(47.29±1.49)ml/(mg·h)。②与空白组相比,模型组大鼠各时间点血清TXB_2含量及TXB_2/6-keto-PGF_(lα)比值均显著降低(P0.05)。与模型组相比,姜炭组大鼠各时间点血清TXB_2含量及TXB_2/6-keto-PGF_(lα)比值均显著升高(P0.05),且药效强度较高。③多成分整合血药浓度与血清TXB_2和TXB_2/6-keto-PGF_(lα)的药效强度变化趋势基本一致,给药4 h后整合血药浓度与药效强度呈正相关。结论:姜炭药效组分在虚寒性出血证大鼠体内的整合药代动力学与温经止血的药效学具有一定的相关性。     

茵陈术附汤药效学与药动学研究进展

茵陈术附汤出自《医学心悟》,主治阴黄证,现代临床多应用于肝炎、慢性肝衰竭等肝脏疾病,疗效显著。基础研究显示,茵陈术附汤对阴黄证、胆汁淤积模型动物具有保护作用,其机制与逆转胆汁酸紊乱、抑制炎症反应、抗肝细胞凋亡、促进胆红素代谢等有关。药动学研究揭示其效应成分以及体内代谢过程的特点。作为该方君药,茵陈及其有效成分在多种肝损伤模型上显示出保肝效应。对茵陈术附汤的临床应用与疗效、药效学评价及作用机制、药动学等研究进展进行综述,为临床疾病治疗及该方的深度研发提供参考。     

The influence of body size on the pharmacodynamic and pharmacokinetic response to clopidogrel and prasugrel: A retrospective analysis of the FEATHER study

Introduction

Patients treated with clopidogrel who have higher body size exhibit greater platelet reactivity than patients with lower body size. In a retrospective analysis of the FEATHER trial, we examined the relationship between platelet response to thienopyridines clopidogrel 75 mg (Clop-75), prasugrel 5 mg (Pras-5), and prasugrel 10 mg (Pras-10) using 3 body size indices: body weight (BW), body mass index (BMI), and body surface area (BSA). Relationships were assessed as continuous variables and as 4 incremental body size groups.

Materials and Methods

Aspirin-treated patients with stable coronary artery disease (N = 72) and a BW range of 45-134 kg received Clop-75, Pras-5, and Pras-10 in a 3-period, blinded, cross-over study. Platelet assays included maximum platelet aggregation (MPA) to 20 μM ADP by light transmission aggregometry, VerifyNow-P2Y12 reaction units (PRU), and vasodilator-associated stimulated phosphoprotein (VASP) phosphorylation platelet reactivity index (PRI). Exposure to active metabolites (AMs) was also assessed.

Results

Body size was a determinant of AM exposure and residual platelet reactivity regardless of type and dose of thienopyridine. BW and BSA demonstrated marginally stronger correlations with platelet reactivity; VASP-PRI demonstrated a stronger correlation with the body size than the other tests. Correlation coefficients ranged from a high of 0.64 (BW vs. PRI on Pras-5) to a low of 0.34 (BMI vs. MPA on Pras-10), but all were statistically significant (p < 0.01).

Conclusions

Using a comprehensive selection of body size indices, AM exposures, platelet function tests, and thienopyridine doses, we demonstrated a consistent inverse relationship between body size and response to clopidogrel and prasugrel.     

Esomeprazole: potent acid suppression in the treatment of acid-related disorders

Esomeprazole (S-omeprazole), an enantiomer of the racemate omeprazole, is the first proton pump inhibitor to be developed as an isomer. This confers improved pharmacokinetics and pharmacodynamics compared with the racemate R/S-omeprazole. The difference in the pharmacokinetics of esomeprazole compared with omeprazole and the R-isomer is due to reductions in total body clearance and first-pass metabolism in the liver. Pharmacodynamic studies showed that esomeprazole 40 mg provides greater intragastric acid control than respective doses of all the other proton pump inhibitors on the market. Several well-designed clinical trials, employing both endoscopic and symptomatic response criteria, have compared the efficacy of esomeprazole with that of other proton pump inhibitors in the management of gastroesophageal reflux disease patients, and in the eradication of Helicobacter pylori. In addition, the efficacy of esomeprazole for the healing and prevention of nonsteroidal anti-inflammatory drug-associated dyspeptic symptoms and ulcers has been established. The aim of this review is to provide an overview of the pharmacokinetics, pharmacodynamics and consequent clinical importance of esomeprazole in the treatment of acid-related disorders.