Effect of Busulphan Dose Adjustment on Regimen-Related Toxicity.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 314-314
Author(s):  
Zuzana Hassan ◽  
Mats Remberger ◽  
Olle Ringden ◽  
Gunnar Oberg ◽  
Albert N. Bekassy ◽  
...  
Keyword(s):  
Total Dose ◽  
Dose Adjustment ◽  
Multiorgan Failure ◽  
Hemorrhagic Cystitis ◽  
Plasma Concentrations ◽  
Conditioning Regimen ◽  
Therapeutic Drug ◽  
Time Interval ◽  
Trough Concentrations

Abstract Stem cell transplantation (SCT) is a successful treatment for many patients with malignant and non-malignant diseases. Conditioning regimen is an important part of SCT, however, regimen-related toxicity (RRT) is a major drawback of myeloablative regimens. In order to decrease RRT, many strategies have been introduced such as therapeutic drug monitoring (TDM) and dose adjustment of busulphan and optimization of time interval between different drugs. The present study, include 470 patients collected from three transplantation centres in Sweden between 1987 and 2002. All patients underwent allogeneic or autologous SCT using busulphan-based conditioning regimen prior to SCT. We investigated the effect of TDM and dose adjustment of busulphan (Bu) on the occurrence of RRT in these patients. Bu was administered orally in total dose of 16 mg/kg with or without dose adjustment and cyclophosphamide administered iv at a total dose of 120 mg/kg. Anti-thymocyte globulin was given to all patients transplanted from unrelated or mismatched donor. Prevention of GVHD consisted of the combination cyclosporin A and four doses of methotrexate or monotherapy with either of the agents. Several strategies for TDM of Bu were based on the actual knowledge, determination of trough levels, the estimation of the area under the concentration-time curve (AUC) using full pharmacokinetics or limited sapling model with follow up of trough concentrations of Bu (Hassan, 1996). The target trough concentrations of Bu were 450–600 ng/ml, the target AUC after the first dose of Bu was 4500–5500 ng. hr/ml. For the purpose of this study, mean Bu plasma concentrations were used. Bu plasma concentrations were measured in all 470 patient, however, TDM was applied in 277 patients, while only determination of plasma concentrations of Bu without dose adjustment was used in 193 patients. Mean trough Bu plasma concentrations followed a Gaussian distribution pattern. One half of the patients had Bu trough concentrations within the range 450–650 ng/ml. The difference between adjusted and non-adjusted groups was observed (57% vs 39%, resp.). Dose adjustments decreased the variation in exposure to Bu between and within the different age groups. Veno-oclussive disease (VOD) was diagnosed in 11/277 patients (4.0%) in patients where Bu doses were adjusted according to plasma concentrations compared to 38/193 patients (19.7%) who were treated without dose adjustment (p<0.001). Busulphan plasma concentrations above 600 ng/ml predispose to VOD. Hemorrhagic cystitis (HC) was found in 8/277 patients (2.9 %) with dose adjustment compared to 26/193 patients (13.5%) without dose adjustment of Bu (p<0.001). Interstitial pneumonitis syndrome (IPS) decreased from 15 % in patients without dose adjustment to 4.3 % in patients whose doses were adjusted (p<0.001), however, almost all patients with IPS had Bu mean trough concentrations above 800 ng/ml. Multiorgan failure was diagnosed in 3/277 patients (1.1 %) with dose adjustment compared to 8/193 patients (4.1 %) without dose adjustment of Bu (p=0.03). These results show, that TDM and dose adjustment of Bu during myeloablative conditioning regimen decrease the occurrence of RRT.

scholarly journals Validation of an HPLC–MS/MS Method for the Determination of Plasma Ticagrelor and Its Active Metabolite Useful for Research and Clinical Practice

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 278
Author(s):  
Jennifer Lagoutte-Renosi ◽  
Bernard Royer ◽  
Vahideh Rabani ◽  
Siamak Davani
Keyword(s):  
Active Metabolite ◽  
Plasma Concentrations ◽  
Antiplatelet Agent ◽  
High Plasma ◽  
Therapeutic Drug ◽  
Routine Practice ◽  
Daily Routine ◽  
Limit Of Quantification ◽  
Wide Range

Ticagrelor is an antiplatelet agent which is extensively metabolized in an active metabolite: AR-C124910XX. Ticagrelor antagonizes P2Y12 receptors, but recently, this effect on the central nervous system has been linked to the development of dyspnea. Ticagrelor-related dyspnea has been linked to persistently high plasma concentrations of ticagrelor. Therefore, there is a need to develop a simple, rapid, and sensitive method for simultaneous determination of ticagrelor and its active metabolite in human plasma to further investigate the link between concentrations of ticagrelor, its active metabolite, and side effects in routine practice. We present here a new method of quantifying both molecules, suitable for routine practice, validated according to the latest Food and Drug Administration (FDA) guidelines, with a good accuracy and precision (<15% respectively), except for the lower limit of quantification (<20%). We further describe its successful application to plasma samples for a population pharmacokinetics study. The simplicity and rapidity, the wide range of the calibration curve (2–5000 µg/L for ticagrelor and its metabolite), and high throughput make a broad spectrum of applications possible for our method, which can easily be implemented for research, or in daily routine practice such as therapeutic drug monitoring to prevent overdosage and occurrence of adverse events in patients.

High-Performance Liquid Chromatographic Determination of Memantine in Human Urine Following Solid-Phase Extraction and Precolumn Derivatization

2013 ◽  
Vol 96 (6) ◽  
pp. 1302-1307 ◽  
Author(s):  
Karim Michail ◽  
Hoda Daabees ◽  
Youssef Beltagy ◽  
Magdy Abd Elkhalek ◽  
Mona Khamis
Keyword(s):  
Human Urine ◽  
High Performance ◽  
Solid Phase ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Therapeutic Drug ◽  
Time Interval ◽  
Precolumn Derivatization ◽  
Uv Detector

Abstract A validated HPLC-UV method is presented for the quantification of urinary memantine hydrochloride, a novel medication approved to treat moderate and advanced cases of Alzheimer's disease. The drug and amantadine hydrochloride, the internal standard, were extracted from human urine using SPE. The extract was then buffered and derivatized at room temperature using o-phthalaldehyde in the presence of N-acetyl-L-cyteine. Chromatographic separation of the formed derivatives was achieved on a C18 column using methanol–water mobile phase adjusted to pH 7 and pumped isocratically at 1 mL/min. The UV detector was set at 340 nm. The chromatographic run time did not exceed 10 min. The LOD and LOQ were 8 and 20 ng/mL, respectively. The RSDs for intraday and interday precisions did not exceed 5.5%. The method was used to monitor memantine hydrochloride in human urine in order to determine an appropriate sampling interval for future noninvasive therapeutic drug monitoring. The assay could also be applied to the determination of amantadine. The described assay showed that a postdosing time interval of 25–75 h seems adequate for sampling and monitoring memantine in urine.

Results compared for tricyclic antidepressants as assayed by liquid chromatography and enzyme immunoassay.

1988 ◽  
Vol 34 (11) ◽  
pp. 2348-2351 ◽  
Author(s):  
R C Dorey ◽  
S H Preskorn ◽  
P K Widener
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Dose Adjustment ◽  
Tricyclic Antidepressants ◽  
Therapeutic Drug ◽  
Low Concentrations ◽  
High Detection ◽  
High Detection Limit ◽  
Highly Correlated

Abstract The tricyclic antidepressants amitriptyline, nortriptyline, imipramine, and desipramine in serum of patients taking one of the drugs were quantified in two laboratories by high-performance liquid chromatography (HPLC) and enzyme-multiplied immunoassay (EMIT; Syva). Results for split samples were highly correlated, but EMIT gave higher results in most cases, and the slopes of the correlation lines for each analyte were greater than 1. Detection limits for the two procedures were such that 18% of the EMIT results for the drug(s) were considered negative, as compared with 4% of the HPLC results. Additional assay of desmethyl or hydroxy antidepressant metabolites by HPLC did not explain the higher EMIT results. The relatively high detection limit for EMIT greatly limits its use in therapeutic drug monitoring, where low concentrations of tricyclic antidepressants are as important as high ones for dose adjustment or determination of compliance. Other problems with EMIT measurement of tricyclic antidepressants are discussed.

scholarly journals Population pharmacokinetics of dolutegravir: influence of drug–drug interactions in a real-life setting

2019 ◽  
Vol 74 (9) ◽  
pp. 2690-2697 ◽  
Author(s):  
Catalina Barcelo ◽  
Manel Aouri ◽  
Perrine Courlet ◽  
Monia Guidi ◽  
Dominique L Braun ◽  
...  
Keyword(s):  
Drug Interactions ◽  
Plasma Concentrations ◽  
Real Life ◽  
Therapeutic Drug ◽  
Population Pharmacokinetic ◽  
Genetic Barrier ◽  
Good Tolerability ◽  
Standard Dosage ◽  
Real Life Setting ◽  
Trough Concentrations

Abstract Objectives Dolutegravir is widely prescribed owing to its potent antiviral activity, high genetic barrier and good tolerability. The aim of this study was to characterize dolutegravir’s pharmacokinetic profile and variability in a real-life setting and to identify individual factors and co-medications affecting dolutegravir disposition. Methods A population pharmacokinetic model was developed using NONMEM®. Relevant demographic factors, clinical factors and co-medications were tested as potential covariates. Simulations based on the final model served to compare expected dolutegravir concentrations under standard and alternative dosage regimens in the case of drug–drug interactions. Results A total of 620 dolutegravir plasma concentrations were collected from 521 HIV-infected individuals under steady-state conditions. A one-compartment model with first-order absorption and elimination best characterized dolutegravir pharmacokinetics. Typical dolutegravir apparent clearance (CL/F) was 0.93 L/h with 32% between-subject variability, the apparent volume of distribution was 20.2 L and the absorption rate constant was fixed to 2.24 h−1. Older age, higher body weight and current smoking were associated with higher CL/F. Atazanavir co-administration decreased dolutegravir CL/F by 38%, while darunavir modestly increased CL/F by 14%. Rifampicin co-administration showed the largest impact on CL/F. Simulations suggest that average dolutegravir trough concentrations are 63% lower after 50 mg/12h with rifampicin compared with a standard dosage of 50 mg/24h without rifampicin. Average trough concentrations after 100 mg/24h and 100 mg/12h with rifampicin are 92% and 25% lower than the standard dosage without rifampicin, respectively. Conclusions Patients co-treated with dolutegravir and rifampicin might benefit from therapeutic drug monitoring and individualized dosage increase, up to 100 mg/12 h in some cases.

Evaluation of Existing Limited Sampling Models for Therapeutic Drug Monitoring of Busulphan in Children and Adults Undergoing SCT.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1150-1150
Author(s):  
Zuzana Hassan ◽  
Marie Sandström ◽  
Moustapha Hassan
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Conditioning Regimen ◽  
Trapezoidal Rule ◽  
Therapeutic Window ◽  
Therapeutic Drug ◽  
High Dose ◽  
Time Interval ◽  
Suitable Model ◽  
Limited Sampling

Abstract Busulphan (Bu) is used in high dose conditioning regimen prior to stem cell transplantation. Bu has a narrow therapeutic window and over- and under-dosing may have a fatal outcome. Bu pharmacokinetics and pharmacodynamics were extensively studied and wide inter- and intra-individual variation was found. Several limited sampling models (LSM) have been developed for Bu administered orally to simplify therapeutic drug monitoring and consequently dose adjustment. The aim of this study was to evaluate the existing LSM in adults and children undergoing conditioning regimen before SCT. Seventy-four patients (62 adults and 12 children) with malignant and non-malignant diseases were analysed. Plasma was sampled at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 5 and 6 hours after the first dose of Bu. Bu was determined using gas chromatography with electron capture detection. The area under the plasma concentration-time curve (AUC) for time interval 0 to 6 hours was determined using Winnonlin program and trapezoidal rule. Results were compared to the estimated AUCs using LSMs (Vassal 1992, Schuler 1994, Hassan 1996, Chatergoon 1997). The best correlation between the AUCs determined using trapezoidal rule and 3-points model by Schuler was found (R²=0.95 for all patients, R²=0.97 for children and R²=0.94 for adults). In children, a correlation between AUCs determined with trapezoidal rule and following LSMs was found: 2-points LSM by Schuler (R²=0.94), LSM by Hassan (R²=0.94), LSM by Vassal (R²=0.81) and 3 of 5 LSMs by Chatergoon (R²=0.85, 0.88 and 0.87, resp.). AUCs in children determined using Winnonlin showed good correlation with both Schuler’s models, model by Hassan and one of 4-points models by Chatergoon. However, the correlation between the AUCs determined using trapezoidal rule and Winnonlin was good in children (R²=0.98), but not in adults (R²=0.65). Thus, several limited sampling models are suitable for AUC estimation in children, while there is only one suitable model for adults. This conclusion is made with reservation that even the trapezoidal rule may underestimate the real AUC dependent on sampling density.

Therapeutic Drug Monitoring of Imatinib and Impact on Clinical Decision Making.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4820-4820 ◽  
Author(s):  
Carolyn Blasdel ◽  
Yanfeng Wang ◽  
Theodore Lagattuta ◽  
Brian Druker ◽  
Laurie Letvak ◽  
...  
Keyword(s):  
Decision Making ◽  
Drug Monitoring ◽  
Dose Adjustment ◽  
Clinical Decision Making ◽  
Plasma Concentrations ◽  
Clinical Decision ◽  
Therapeutic Drug ◽  
Dose Increase ◽  
Qrt Pcr ◽  
Drug Concentrations

Abstract OBJECTIVES: Imatinib (IM) has demonstrated durable clinical efficacy in the majority of chronic myeloid leukemia (CML) patients. Optimal response may be influenced by multiple innate and external factors, some of which may be controlled by monitoring plasma concentrations of the drug. This abstract reports 6 cases where analyzing plasma IM trough concentrations (Cmin) in patients treated with three commonly used IM doses (400, 600, and 800 mg daily) influenced clinical decision making. METHODS: IM trough blood samples were collected at a time before that day’s IM dosing. Plasma concentrations of IM were determined by a validated LC/MS/MS method. RESULTS: In large population studies of CML patients enrolled in Phase I, II, and III clinical trials, the mean Cmin levels of IM at 400 mg qd, 600 mg qd, and 400 mg bid doses were: 981 (±543, 55%, n=394), 1572 (±1032, 66%, n=14), and 3479 (±1264, 36%, n=14) ng/mL, respectively. Large inter-patient variability was shown at all three doses. Of the 6 cases detailed in the table below, 4 (ID 1, 3, 4, and 5) had dose reduction due to tolerability concerns with subsequent improvement of symptoms following dose adjustment. One patient (ID 2) had a dose increase because of a poor qRT-PCR response. Another (ID 6) had a dose increase due to low plasma IM exposure resulting from drug-drug interaction with phenytoin, a known inducer of CYP3A4 (the major metabolizing isozyme for IM). After dose adjustment, all six patients showed good clinical response to IM treatment. The new mean Cmin value in these patients was 2000 (±471) ng/mL, representing a 24% coefficient of variability. CONCLUSIONS: Although the data is limited, IM drug monitoring proved useful in managing tolerability, lack of efficacy, adherence or potential drug interactions that modulate imatinib drug concentrations. More prospective studies are needed to demonstrate the value of IM drug monitoring in routine clinical practice. Patient ID Age, Sex CML Stage IM Daily Dose 1st Cmin (ng/mL) Reason for Dose Change New Dosing Regimen New Cmin (ng/mL) CP, chronic phase1 1 54, f CP 200 mg bid, Jan 03 3048, Sep 05 transfusion-dependent, anemia, Sep 05 300 mg, Oct 05 2130, Jan 06 2 9, f CP 300 mg, Jan 05 not done qRT-PCR 0.016, Jan 06 400 mg, Jan 06 2341, Jul 06 3 13, f CP 300 mg bid, May 05; 700 mg, Aug 05; 600 mg, Sep 05 1966, Feb 06 nausea, fatigue, arthralgias, myalgia, ongoing 400 mg, Mar 06 1222, May 06 4 67, f CP 400 mg, Feb 05 not done myelosuppression, Mar 05 200 mg, Mar 05 1928, May 06 5 53, f CP 400 mg, Apr 03; 600 mg, May 03; 800 mg, Jul 04 not done inflammatory pulmonary reaction with shortness of breath; dose held, Mar 05 400 mg, Oct 05 2378, May 06 6 73, m CP 350 mg, on phenytoin, Apr 99 35, Jun 99 stopped phenytoin, Jul 99 500 mg, Jul 99 not done; qRT-PCR negative, Jul 06

scholarly journals Case Report: Low Hematocrit Leading to Tacrolimus Toxicity

2021 ◽  
Vol 12 ◽  
Author(s):  
Alexandre Piletta-Zanin ◽  
Aurélie De Mul ◽  
Nathalie Rock ◽  
Pierre Lescuyer ◽  
Caroline F. Samer ◽  
...  
Keyword(s):  
Whole Blood ◽  
Calcineurin Inhibitor ◽  
Plasma Concentrations ◽  
Therapeutic Index ◽  
Therapeutic Drug ◽  
Pharmacokinetic Variability ◽  
Narrow Therapeutic Index ◽  
Low Concentrations ◽  
Monitoring Procedure ◽  
Trough Concentrations

Tacrolimus is a calcineurin inhibitor characterized by a narrow therapeutic index and high intra- and inter-individual pharmacokinetic variability. Therapeutic drug monitoring in whole-blood is the standard monitoring procedure. However, tacrolimus extensively binds to erythrocytes, and tacrolimus whole-blood distribution and whole-blood trough concentrations are strongly affected by hematocrit. High whole-blood tacrolimus concentrations at low hematocrit may result in high unbound plasma concentrations and increased toxicity. We present the case of a 16-year-old girl with kidney and liver transplant in whom low concentrations of tacrolimus in the context of low hematocrit led to significant increase in the dosage of tacrolimus and participate, along with a genetic polymorphism of ABCB1, in nephrotoxicity.

scholarly journals Clinical-Based vs. Model-Based Adaptive Dosing Strategy: Retrospective Comparison in Real-World mRCC Patients Treated with Sunitinib

2021 ◽  
Vol 14 (6) ◽  
pp. 494
Author(s):  
Florent Ferrer ◽  
Jonathan Chauvin ◽  
Bénédicte DeVictor ◽  
Bruno Lacarelle ◽  
Jean-Laurent Deville ◽  
...  
Keyword(s):  
Active Metabolite ◽  
Dose Adjustment ◽  
Complete Response ◽  
Therapeutic Window ◽  
Therapeutic Drug ◽  
Model Based ◽  
Target Exposure ◽  
Number Of Patients ◽  
Trough Concentrations ◽  
Dosing Strategy

Different target exposures with sunitinib have been proposed in metastatic renal cell carcinoma (mRCC) patients, such as trough concentrations or AUCs. However, most of the time, rather than therapeutic drug monitoring (TDM), clinical evidence is preferred to tailor dosing, i.e., by reducing the dose when treatment-related toxicities show, or increasing dosing if no signs of efficacy are observed. Here, we compared such empirical dose adjustment of sunitinib in mRCC patients, with the parallel dosing proposals of a PK/PD model with TDM support. In 31 evaluable patients treated with sunitinib, 53.8% had an empirical change in dosing after treatment started (i.e., 46.2% decrease in dosing, 7.6% increase in dosing). Clinical benefit was observed in 54.1% patients, including 8.3% with complete response. Overall, 58.1% of patients experienced treatment discontinuation eventually, either because of toxicities or progressive disease. When choosing 50–100 ng/mL trough concentrations as a target exposure (i.e., sunitinib + active metabolite N-desethyl sunitinib), 45% patients were adequately exposed. When considering 1200–2150 ng/mL.h as a target AUC (i.e., sunitinib + active metabolite N-desethyl sunitinib), only 26% patients were in the desired therapeutic window. TDM with retrospective PK/PD modeling would have suggested decreasing sunitinib dosing in a much larger number of patients as compared with empirical dose adjustment. Indeed, when using target trough concentrations, the model proposed reducing dosing for 61% patients, and up to 84% patients based upon target AUC. Conversely, the model proposed increasing dosing in 9.7% of patients when using target trough concentrations and in 6.5% patients when using target AUC. Overall, TDM with adaptive dosing would have led to tailoring sunitinib dosing in a larger number of patients (i.e., 53.8% vs. 71–91%, depending on the chosen metrics for target exposure) than a clinical-based decision. Interestingly, sunitinib dosing was empirically reduced in 41% patients who displayed early-onset severe toxicities, whereas model-based recommendations would have immediately proposed to reduce dosing in more than 80% of those patients. This observation suggests that early treatment-related toxicities could have been partly avoided using prospective PK/PD modeling with adaptive dosing. Conversely, the possible impact of model-based adapted dosing on efficacy could not be fully evaluated because no clear relationship was found between baseline exposure levels and sunitinib efficacy measured at 3 months.

scholarly journals Therapeutic Drug Monitoring of Busulfan in Patients Undergoing Hematopoietic Cell Transplantation: A Pilot Single-Center Study in Taiwan

2021 ◽  
Vol 14 (7) ◽  
pp. 613
Author(s):  
Rong-Long Chen ◽  
Li-Hua Fang ◽  
Xin-Yi Yang ◽  
Mohsin El Amrani ◽  
Esther Veronique Uijtendaal ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Dose Adjustment ◽  
Conditioning Regimen ◽  
Hematopoietic Cell ◽  
Therapeutic Drug ◽  
Single Center ◽  
Taiwanese Population ◽  
Single Center Study ◽  
Center Study

(1) Background: Busulfan has been used as a conditioning regimen in allogeneic hematopoietic cell stem transplantation (HSCT). Owing to a large inter-individual variation in pharmacokinetics, therapeutic drug monitoring (TDM)-guided busulfan dosing is necessary to reduce graft failure and relapse rate. As there exists no TDM of busulfan administration for HCT in Taiwan, we conducted a pilot study to assess the TDM-dosing of busulfan in the Taiwanese population; (2) Methods: Seven patients with HCT from The Koo Foundation Sun Yat-Sen Cancer Center, Taipei, Taiwan, received conditioning regimens consisting of intravenous busulfan and other chemotherapies. After the initial busulfan dose, blood samples were collected for busulfan TDM at 5 min, 1 h, 2 h, and 3 h. Busulfan was extracted and detected by performing stable-isotope dilution LC–MS/MS. Plasma busulfan concentration was quantified and used for dose adjustment. Potential adverse effects of busulfan, such as mucositis and hepatic veno-occlusive disease (VOD), were also evaluated; (3) Results: The LC–MS/MS method was validated with an analyte recovery of 88–99%, within-run and between-run precision of <15%, and linearity ranging from 10 to 10,000 ng/mL. Using TDM-guided busulfan dosing, dose adjustment was necessary and performed in six out of seven patients (86%) with successful engraftments in all patients (100%). Mild mucositis was observed, and VOD was diagnosed in only one patient; (4) Conclusions: This single-center study in Taiwan demonstrated the importance of busulfan TDM in increasing the success rate of HCT transplantation. It is also necessary to further investigate the optimal busulfan target value in the Taiwanese population in the future.

scholarly journals Determination of Serum/Plasma Concentrations of Psychotropic Drugs in Therapeutic Drug Monitoring

2021 ◽  
pp. 3-13
Author(s):  
I. I. Miroshnichenko ◽  
N. V. Baymeeva ◽  
A. I. Platova
Keyword(s):  
Mental Health ◽  
Therapeutic Drug Monitoring ◽  
Psychotropic Drugs ◽  
Drug Monitoring ◽  
Antipsychotic Drugs ◽  
Plasma Concentrations ◽  
Mental Health Research ◽  
Therapeutic Drug ◽  
Made In

The article considers the main methodological methods of therapeutic drug monitoring (TDM) of psychotropic drugs. Analytical methods that allow performing these studies have been described. It has been given the interpretation, examples and brief results of two studies of TDM of antipsychotic drugs made in FSBSI “Mental Health Research Center” and Psychiatric hospital No.14 in Moscow.

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