他克莫司的不良反应

本文综述近几年在国内报道的他克莫司的药物不良反应,为更合理使用该药提供参考。     

他克莫司胶囊的溶出度研究

目的考察他克莫司胶囊的溶出度及其体外释药性质。方法照溶出度测定法中国药典2005年版二部附录XC溶出度实验法第三法(桨法),以水100mL为溶出介质,采用HPLC法测定,HypersilC8柱(250mm×4.6mm,5μm),乙腈-水(75∶25)为流动相,流速为1.0mL·min-1,检测波长为220nm。按外标法以峰面积计算。结果他克莫司质量浓度在1.10～13.15g.L-1范围内线性关系良好,r=0.9999(n=5),回收率为97.95%～98.92%,RSD为0.62%～1.81%。结论该方法简便、准确、灵敏,他克莫司胶囊具有良好的溶出度,符合规定。     

他克莫司的药物相互作用研究进展

目的 介绍他克莫司和其他临床常用药物的相互作用,为临床安全应用提供参考.方法 主要以国外发表的论文为基础,对他克莫司和各种药物的相互作用分别进行归纳和分析.结果 他克莫司的药物相互作用包括药动学、药效学两个方面,从而使药物血药浓度或免疫抑制作用发生改变.结论 他克莫司与各种药物联合应用时应尽量避免有害相互作用的产生,以达到安全、有效的治疗目的.     

他克莫司的工业化研究

日本藤泽公司通过对他克莫司产生菌筑波链霉菌的选育,发酵条件优化,提取方法改良,以及建立简单、快速、可信度高的ＨＰＬＣ定量分析方法,顺利实现他克莫司的工业化生产,产率比原始菌株和原始发酵条件提高了３００倍,产物的异构化得到控制,产品纯度达到９９％以上。     

他克莫司发酵条件的研究

通过正交试验优化了他克莫司产生菌的发酵培养基,研究了不同发酵条件对他克莫司产量的影响。结果显示在最优条件下,进行了5m3发酵罐的发酵试验,发酵144h他克莫司的产率为330μg·mL-1,达到了工业化生产的要求,为进一步放大生产奠定了基础。     

他克莫司致可逆性室间隔肥厚

1例52岁女性患者因重症再生障碍性贫血行异基因造血干细胞移植术,术后服用环孢素预防移植物抗宿主病。2个月后因肾功能不全,换用他克莫司0.5~1.5 mg,2次/d口服,其血药谷浓度为2.4~7.2μg/L。此后患者逐渐出现气短、疲乏,夜间不能平卧等症状,服用他克莫司50 d后心脏超声检查示室间隔增厚（13 mm）。停用他克莫司,换用西罗莫司和吗替麦考酚酯胶囊后上述症状逐渐好转,20 d后心脏超声检查示室间隔厚度为10 mm。     

免疫抑制剂他克莫司在肾脏移植的应用

目的：对免疫抑制剂他克莫司在肾脏移植应用的进展进行综述。方法：综述近年来他克莫司在肾脏移植应用的有关文献。结果：他克莫司具有极强的免疫抑制作用，可以降低移植肾早期急性排斥反应的发生率，但现有临床资料显示它并不能延长移植肾的中长期存活期。和环孢素相比，他克莫司治疗的病人高血压和高脂血症的发生率较低，但神经并发症和糖尿病发生率高。结论：他克莫司是一种有效的免疫抑制剂，可用于肾脏移植的基础治疗和转换治疗，为肾脏移植免疫抑制治疗方案的制定提供了选择余地。     

脏器移植后应用他克莫司引起的高血压以及神经系统并发症

近 5 0ａ来 ,脏器移植的患者日益增多 ,脏器移植后并发症问题的处理已成为研究的热点。他克莫司 (ｔａｃｒｏｌｉｍｕｓ ,ＦＫ5 0 6,ｐｒｏｇｒａｆ,普乐可复 )是一个新型的免疫抑制剂 ,在 1989年就开始应用于器官移植的抗排斥方面 ,且已有大量的文献报道。近年来 ,在肝脏、肾脏、心脏、胰、骨髓移植的患者中越来越多地应他克莫司 ,发现它引起的高血压、神经系统的并发症最为常见[1] ,对电解质、血脂、血糖等也都出现不良反应。对肝移植术后患者的预后影响尤为突出。本文就近几年来他克莫司在脏器移植后用法及对ＢＰ和神经系统的不良反应作…     

他克莫司药效学研究进展简

他克莫司是一种钙调磷酸酶抑制剂,主要是通过抑制T细胞活化相关细胞因子（IL-2、IL-3、IL-4、IL-5、IFN-γ、TNF-α、GM-CSF）的转录和IL-2、IL-7受体的表达发挥免疫抑制作用。此外,临床及动物实验中均显示他克莫司在预防及治疗器官移植排斥反应方面效果显著。主要不良反应为肾毒性、神经毒性、高血压、糖尿病、牙龈增生等。     

他克莫司联合氟康唑治疗对他克莫司血药浓度的影响

目的:考查器官移植术后免疫抑制剂他克莫司与抗真菌药氟康唑联合应用对前者血药浓度的影响. 方法:对2004年9月-12月本院器官移植患者口服他克莫司同时口服或注射氟康唑的病例共计72例,除去32例氟康唑治疗不足1个疗程(7d)者,对40例患者的他克莫司血药浓度进行分析.送检的他克莫司血样用微粒子酶免疫法(MEIA法)进行血药浓度监测. 结果:在纳入研究的40例患者中,联合他克莫司口服(35例)或静脉输注(5例)氟康唑后,他克莫司第1日的血浆谷浓度分别升高为联合用药前的1.9倍和2.2倍,到第4日时他克莫司的给药剂量分别下降为联合用药前的67.3% 和70%. 结论:在移植术后早期,他克莫司联合氟康唑治疗可使他克莫司血浆谷浓度升高,应及时对他克莫司的剂量做出调整,避免因药物浓度的过高或过低产生毒性反应或引起排斥反应.     

他克莫司在肾移植术后肝功能异常中的应用

目的 :观察他克莫司 (tacrolimus)在肾移植术后肝功能异常病人中应用的有效性及安全性。方法 :将 47例病人分成环孢素组 ,给予环孢素 1 .5～3 .5mg·kg-1,po,bid ,作对照 ;他克莫司治疗组 ,给予他克莫司 0 .0 5～ 0 .1 5mg·kg-1,po,bid。 2组均同时给予霉酚酸酯、泼尼松及保肝药物治疗 ,观察 3mo。结果 :治疗后 90d,他克莫司组的ALT ,SCr,BUN指标分别下降 (1 0 0±s 45 )IU·L-1,(5 8± 3 9)μmol·L-1和 (7± 4)mmol·L-1,(P <0 .0 1 ) ;环孢素组的ALT下降 (4 6± 2 5 )IU·L-1,(P <0 .0 1 ) ,SCr及BUN分别升高 (4 3± 69) μmol·L-1(P <0 .0 1 )和(3± 6)mmol·L-1(P <0 .0 5 )。 2组间比较P <0 .0 5或P <0 .0 1。不良反应环孢素组出现 1 3例 ,他克莫司组出现 1例。结论 :他克莫司在肾移植术后肝功能异常病人中应用有利于肝功能的恢复 ,是安全有效的免疫抑制药     

五酯胶囊对肾移植受者他克莫司血浓度影响的临床研究

目的：研究五酯胶囊（Wuzhi-capsule,WZ）与他克莫司（Tacrolimus,Tac）联合应用对肾移植受者Tac血浓度的影响。方法：45名服用Tac＋WZ患者为试验组,45名单服Tac患者为对照组,以Tac全血浓度及肝、肾功能生化检测指标作为临床评价指标。结果：合用WZ患者Tac全血浓度与合用前比较明显增加（P〈0．01）,与对照组比较亦有显著性提高（P〈0．01）。WZ与Tac合用对肝、肾功能无明显影响。结论：WZ能明显升高肾移植受者Tac血浓度。在升高Tac血浓度的同时,WZ并不增加Tac的肝肾毒性反应。WZ与Tac合用可减少Tac用药量,节省Tac费用。     

ELISA法监测肝移植患者他克莫司全血浓度

目的通过监测肝移植患者他克莫司全血浓度,观察并建立他克莫司在三联免疫抑制用药方案中的理想治疗窗,为临床合理应用提供参考。方法用ELISA法测定他克莫司全血浓度,对138例患者的1190例次监测结果进行比较分析。结果他克莫司全血浓度随移植后时间延长而逐渐下降。肝移植后1个月内、第2~3个月、第4~6个月和>6个月时,用ELISA法监测他克莫司全血谷浓度的推荐治疗窗范围应分别为8~15、6~12、5~10、3~8μg·L-1,较为适宜。结论常规监测他克莫司全血浓度,参考推荐治疗窗范围调整给药方案,可获得满意的免疫抑制治疗效果。     

Factors affecting variability in distribution of tacrolimus in liver transplant recipients

AIMS: Therapeutic drug monitoring (TDM) of tacrolimus is complicated by conflicting data on the correlation between tacrolimus trough blood concentrations and the incidence of rejection. The aim of this cross-sectional study was to investigate the blood distribution and protein binding of tacrolimus in liver transplant recipients to explore better predictors of clinical outcome. METHODS: Blood and plasma distribution of 3H-dihydro-tacrolimus was investigated in 40 liver transplant recipients using Ficoll Paque and density gradient ultracentrifugation, respectively, and equilibrium dialysis to investigate plasma protein binding. RESULTS: In blood tacrolimus was mainly associated with the erythrocyte fraction (83.2%, range 74.6-94.9%), followed by diluted plasma (16.1%, range 4.5-24.9%), and lymphocyte fraction (0.61%, range: 0.11-1.53%). In plasma, lipoprotein deficient serum fraction (54.2%, range 38.5-68.2%) was the main reservoir of tacrolimus. The unbound fraction of tacrolimus was found to be 0.47 +/- 0.18% (range 0.07-0.89%). The percentage of tacrolimus associated with the lymphocytes (0.8 +/- 0.4 vs 0.3 +/- 0.1%, P = 0.012) and estimated unbound concentration (0.42 +/- 0.21 ng l-1vs 0.24 +/- 0.08 ng l-1, P < 0.001) of tacrolimus were significantly different in stable transplant recipients and those experiencing rejection. Haematocrit and red blood cell count significantly influenced the percentage of tacrolimus associated with erythrocytes. The fraction unbound of tacrolimus was correlated with alpha1-acid glycoprotein and high density lipoprotein cholesterol concentrations. CONCLUSIONS: Tacrolimus unbound concentration was observed to be lower in liver transplant recipients experiencing rejection and further study is required to evaluate its utility in the TDM of tacrolimus.     

Pharmacokinetic considerations related to therapeutic drug monitoring of tacrolimus in kidney transplant patients

Introduction: Tacrolimus (Tac) is the cornerstone of immunosuppressive therapy after solid organ transplantation and will probably remain so. Excluding belatacept, no new immunosuppressive drugs were registered for the prevention of acute rejection during the last decade. For several immunosuppressive drugs, clinical development halted because they weren’t sufficiently effective or more toxic.

Areas covered: Current methods of monitoring Tac treatment, focusing on traditional therapeutic drug monitoring (TDM), controversies surrounding TDM, novel matrices, pharmacogenetic and pharmacodynamic monitoring are discussed.

Expert opinion: Due to a narrow therapeutic index and large interpatient pharmacokinetic variability, TDM has been implemented for individualization of Tac dose to maintain drug efficacy and minimize the consequences of overexposure. The relationship between predose concentrations and the occurrence of rejection or toxicity is controversial. Acute cellular rejection also occurs when the Tac concentration is within the target range, suggesting that Tac whole blood concentrations don’t necessarily correlate with pharmacological effect. Intracellular Tac, the unbound fraction of Tac or pharmacodynamic monitoring could be better biomarkers/tools for adequate Tac exposure – research into this has been promising. Traditional TDM, perhaps following pre-emptive genotyping for Tac-metabolizing enzymes, must suffice for a few years before these strategies can be implemented in clinical practice.     

Population pharmacokinetics and Bayesian estimation of tacrolimus exposure in paediatric liver transplant recipients

Aims

The objectives of this study were to develop a population pharmacokinetic (PopPK) model for tacrolimus in paediatric liver transplant patients and determine optimal sampling strategies to estimate tacrolimus exposure accurately.

Methods

Twelve hour intensive pharmacokinetic profiles from 30 patients (age 0.4–18.4 years) receiving tacrolimus orally were analysed. The PopPK model explored the following covariates: weight, age, sex, type of transplant, age of liver donor, liver function tests, albumin, haematocrit, drug interactions, drug formulation and time post-transplantation. Optimal sampling strategies were developed and validated with jackknife.

Results

A two-compartment model with first-order absorption and elimination and lag time described the data. Weight was included on all pharmacokinetic parameters. Typical apparent clearance and central volume of distribution were 12.1 l h⁻¹ and 31.3 l, respectively. The PopPK approach led to the development of optimal sampling strategies, which allowed estimation of tacrolimus pharmacokinetics and area under the concentration–time curve (AUC) on the basis of practical sampling schedules (three or four sampling times within 4 h) with clinically acceptable prediction error limit. The mean bias and precision of the Bayesian vs. reference (trapezoidal) AUCs ranged from −2.8 to −1.9% and from 7.4 to 12.5%, respectively.

Conclusions

The PopPK of tacrolimus and empirical Bayesian estimates represent an accurate and convenient method to predict tacrolimus AUC_(0–12) in paediatric liver transplant recipients, despite high between-subject variability in pharmacokinetics and patient demographics. The developed optimal sampling strategies will allow the undertaking of prospective trials to define the tacrolimus AUC-based therapeutic window and dosing guidelines in this population.     

Pharmacokinetics of tacrolimus converted from twice-daily formulation to once-daily formulation in Chinese stable liver transplant recipients

Aim:

To evaluate the pharmacokinetics of tacrolimus in Chinese stable liver transplant recipients converted from immediate release (IR) tacrolimus-based immunosuppression to modified release (MR) tacrolimus-based immunosuppression.

Methods:

Open-label, multi-center study with a one-way conversion design was conducted. Eighty-three stable liver recipients (6–24 months post-transplant) with normal renal and stable hepatic function were converted from IR tacrolimus twice-daily treatment to MR tacrolimus once-daily treatment on a 1:1 (mg: mg) total daily dose basis. Twenty-four hour pharmacokinetic studies were carried out on d 0 (pre-conversion), d 1, and d 84 (post-conversion).

Results:

The area under the blood concentration–time curve of MR tacrolimus from 0 to 24 h (AUC_0–24) on d 1 was comparable to that of IR tacrolimus on d 0, with a 90% confidence interval (CI) for MR/IR tacrolimus of 92%–97%. The AUC_0–24 value for MR tacrolimus on d 84 with the daily dose increased by 14% was approximately 17% lower than that for IR tacrolimus. The 90% CI was 77%–90%, outside the bioequivalence range of 80%–125%. There was a good correlation between AUC_0–24 and concentration at 24 h (C₂₄) for IR tacrolimus (d 0, r=0.930) and MR tacrolimus (d 1, r=0.936; d 84, r=0.903).

Conclusion:

The exposure to tacrolimus when administered MR tacrolimus once daily is not equivalent to that for IR tacrolimus twice daily after an 84-day conversion in Chinese stable liver transplant recipients. The dose should be adjusted on the basis of trough levels. The therapeutic drug monitoring for patients treated with IR tacrolimus is considered to be applicable to MR tacrolimus.