scholarly journals Therapeutic Reference Ranges for Psychotropic Drugs: A Protocol for Systematic Reviews

2021 ◽  
Vol 12 ◽  
Author(s):  
Xenia M. Hart ◽  
Luzie Eichentopf ◽  
Xenija Lense ◽  
Thomas Riemer ◽  
Katja Wesner ◽  
...  

Background: For many psychotropic drugs, monitoring of drug concentrations in the blood (Therapeutic Drug Monitoring; TDM) has been proven useful to individualize treatments and optimize drug effects. Clinicians hereby compare individual drug concentrations to population-based reference ranges for a titration of prescribed doses. Thus, established reference ranges are pre-requisite for TDM. For psychotropic drugs, guideline-based ranges are mostly expert recommendations derived from a conglomerate of cohort and cross-sectional studies. A systematic approach for identifying therapeutic reference ranges has not been published yet. This paper describes how to search, evaluate and grade the available literature and validate published therapeutic reference ranges for psychotropic drugs.Methods/Results: Following PRISMA guidelines, relevant databases have to be systematically searched using search terms for the specific psychotropic drug, blood concentrations, drug monitoring, positron emission tomography (PET) and single photon emission computed tomography (SPECT). The search should be restricted to humans, and diagnoses should be pre-specified. Therapeutic references ranges will not only base upon studies that report blood concentrations in relation to clinical effects, but will also include implications from neuroimaging studies on target engagement. Furthermore, studies reporting concentrations in representative patient populations are used to support identified ranges. Each range will be assigned a level of underlying evidence according to a systematic grading system.Discussion: Following this protocol allows a comprehensive overview of TDM literature that supports a certain reference range for a psychotropic drug. The assigned level of evidence reflects the validity of a reported range rather than experts' opinions.

2021 ◽  
Vol 45 (3) ◽  
pp. 183-187
Author(s):  
Dao-Hai Cheng ◽  
Zhen-Guang Huang ◽  
Jing-Bing Zhu

Abstract Objectives Heat treatment is a convenient measure for pathogens inactivation. The authors investigated the effects of this method on blood concentrations of six commonly therapeutic drugs. Methods Plasma and whole blood were pretreated with or without heating at 56 °C for 30 min, and drug concentrations of vancomycin, methotrexate, valproic acid, digoxin, carbamazepine, and cyclosporine were examined. Results Increased valproic acid levels after plasma heating (63.2 ± 30.2 vs. 62.1 ± 29.8 mg/L, mean recovery 102.0%) and whole blood heating (64.5 ± 30.5 vs. 62.1 ± 29.8 mg/L, mean recovery 104.6%) were observed (both p<0.05), but these differences were not considered clinically important. Recoveries of vancomycin in heat treatments varied widely, with an average and significant decrease of 15.8% in value after whole blood heating (11.7 ± 8.1 vs. 13.7 ± 8.6 mg/L, p<0.05). Conclusions Plasma or whole blood heating at 56 °C for 30 min are feasible in pathogens inactivation during monitoring methotrexate, valproic acid, digoxin, carbamazepine, and cyclosporine. However, such pretreatment seems inappropriate in monitoring vancomycin concentrations. Those results highlight the need for caution when applying heat treatment for pathogens inactivation in therapeutic drug monitoring.


2020 ◽  
Vol 44 (7) ◽  
pp. 688-696
Author(s):  
Sheng Feng ◽  
Brandi Bridgewater ◽  
Erin C Strickland ◽  
Gregory McIntire

Abstract Epilepsy is a common neurologic disease that requires treatment with one or more medications. Due to the polypharmaceutical treatments, potential side effects, and drug-drug interactions associated with these medications, therapeutic drug monitoring is important. Therapeutic drug monitoring is typically performed in blood due to established clinical ranges. While blood provides the benefit of determining clinical ranges, urine requires a less invasive collection method, which is attractive for medication monitoring. As urine does not typically have established clinical ranges, it has not become a preferred specimen for monitoring medication adherence. Thus, large urine clinical data sets are rarely published, making method development that addresses reasonable concentration ranges difficult. An initial method developed and validated in-house utilized a universal analytical range of 50–5,000 ng/mL for all antiepileptic drugs and metabolites of interest in this work, namely carbamazepine, carbamazepine-10,11-epoxide, eslicarbazepine, lamotrigine, levetiracetam, oxcarbazepine, phenytoin, 4-hydroxyphenytoin, and topiramate. This upper limit of the analytical range was too low leading to a repeat rate of 11.59% due to concentrations &gt;5,000 ng/mL. Therefore, a new, fast liquid chromatography–tandem mass spectrometry (LC–MS-MS) method with a run time under 4 minutes was developed and validated for the simultaneous quantification of the previously mentioned nine antiepileptic drugs and their metabolites. Urine samples were prepared by solid-phase extraction and analyzed using a Phenomenex Phenyl-Hexyl column with an Agilent 6460 LC–MS-MS instrument system. During method development and validation, the analytical range was optimized for each drug to reduce repeat analysis due to concentrations above the linear range and for carryover. This reduced the average daily repeat rate for antiepileptic testing from 11.59% to 4.82%. After validation, this method was used to test and analyze patient specimens over the course of approximately one year. The resulting concentration data were curated to eliminate specimens that could indicate an individual was noncompliant with their therapy (i.e., positive for illicit drugs) and yielded between 20 and 1,700 concentration points from the patient specimens, depending on the analyte. The resulting raw quantitative urine data set is presented as preliminary reference ranges to assist with interpreting urine drug concentrations for the nine aforementioned antiepileptic medications and metabolites.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sabrina Ritscher ◽  
Milena Hoyer ◽  
Cora Wunder ◽  
Nicholas Obermüller ◽  
Stefan W. Toennes

Abstract Detection of antihypertensive drugs in biological samples is an important tool to assess the adherence of hypertensive patients. Urine and serum/plasma screenings based on qualitative results may lead to misinterpretations regarding drugs with a prolonged detectability. The aim of the present study was to develop a method that can be used for therapeutic drug monitoring (TDM) of antihypertensive drugs with focus on adherence assessment. Therefore, a method for quantification of four diuretics and four β-blockers using high-performance liquid chromatography-mass spectrometric analysis (LC-MS/MS) of combined acidic and basic serum extracts was developed and validated. The method was applied to 40 serum samples from 20 patients in a supervised medication setting (trough and peak serum samples). Literature data on therapeutic concentration ranges, as well as dose-related drug concentrations (calculated from data of pharmacokinetic studies) were used to evaluate adherence assessment criteria. Concentrations were measured for bisoprolol (n = 9 patients), metoprolol (n = 7), nebivolol (n = 1), canrenone (n = 2, metabolite of spironolactone), hydrochlorothiazide (n = 10) and torasemide (n = 8). The measured concentrations were within the therapeutic reference ranges, except for 24% of the samples (mainly β-blockers). In contrast, all measured concentrations were above the lower dose-related concentration (DRC), which appears superior in evaluating adherence. In conclusion, the quantitative analysis of antihypertensive drugs in serum samples and its evaluation on the basis of the individually calculated lower DRC is a promising tool to differentially assess adherence. This method could possibly detect a lack of adherence or other causes of insufficient therapy more reliably than qualitative methods.


2021 ◽  
Vol 14 ◽  
pp. 175628482199990
Author(s):  
Sonia Facchin ◽  
Andrea Buda ◽  
Romilda Cardin ◽  
Nada Agbariah ◽  
Fabiana Zingone ◽  
...  

Anti-drug antibodies can interfere with the activity of anti-tumor necrosis factor (TNF) agents by increasing drug clearance via direct neutralization. The presence of anti-drug antibodies is clinically relevant when trough drug concentrations are undetectable or sub-therapeutic. However, traditional immunoassay is not easily and rapidly accessible, making the translation of the results into treatment adjustment difficult. The availability of a point-of-care (POC) test for therapeutic drug monitoring (TDM) might represent an important step forward for improving the management of inflammatory bowel disease (IBD) patients in clinical practice. In this pilot study, we compared the results obtained with POC tests with those obtained by enzyme-linked immunosorbent assay (ELISA) in a group of IBD patients treated with Infliximab (IFX). We showed that POC test can reliably detect presence of antibody-to-IFX with 100% of specificity and 76% sensitivity, in strong agreement with the ELISA test ( k-coefficient = 0.84).


Author(s):  
Susanne Weber ◽  
Sara Tombelli ◽  
Ambra Giannetti ◽  
Cosimo Trono ◽  
Mark O’Connell ◽  
...  

AbstractObjectivesTherapeutic drug monitoring (TDM) plays a crucial role in personalized medicine. It helps clinicians to tailor drug dosage for optimized therapy through understanding the underlying complex pharmacokinetics and pharmacodynamics. Conventional, non-continuous TDM fails to provide real-time information, which is particularly important for the initial phase of immunosuppressant therapy, e.g., with cyclosporine (CsA) and mycophenolic acid (MPA).MethodsWe analyzed the time course over 8 h of total and free of immunosuppressive drug (CsA and MPA) concentrations measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 16 kidney transplant patients. Besides repeated blood sampling, intravenous microdialysis was used for continuous sampling. Free drug concentrations were determined from ultracentrifuged EDTA-plasma (UC) and compared with the drug concentrations in the respective microdialysate (µD). µDs were additionally analyzed for free CsA using a novel immunosensor chip integrated into a fluorescence detection platform. The potential of microdialysis coupled with an optical immunosensor for the TDM of immunosuppressants was assessed.ResultsUsing LC-MS/MS, the free concentrations of CsA (fCsA) and MPA (fMPA) were detectable and the time courses of total and free CsA comparable. fCsA and fMPA and area-under-the-curves (AUCs) in µDs correlated well with those determined in UCs (r≥0.79 and r≥0.88, respectively). Moreover, fCsA in µDs measured with the immunosensor correlated clearly with those determined by LC-MS/MS (r=0.82).ConclusionsThe new microdialysis-supported immunosensor allows real-time analysis of immunosuppressants and tailor-made dosing according to the AUC concept. It readily lends itself to future applications as minimally invasive and continuous near-patient TDM.


1995 ◽  
Vol 41 (9) ◽  
pp. 1292-1296 ◽  
Author(s):  
I Firdaous ◽  
A Hassoun ◽  
J B Otte ◽  
R Reding ◽  
J P Squifflet ◽  
...  

Abstract Tacrolimus is a relatively new immunosuppressant used in organ transplantation to prevent graft rejection. However, its use is not devoid of side effects, making it important to maintain blood concentrations within therapeutic ranges. Several analytical methods are currently available for routine drug monitoring. However, these methods are based on use of the same monoclonal antibody, which also cross-reacts with some metabolites, resulting in overestimation of some blood concentrations. Even though this antibody appears appropriate for therapeutic drug monitoring, no reference method measures only the parent drug, mainly because of the poor absorptivity of tacrolimus in ultraviolet light. We have developed a method displaying an increased specificity towards the unchanged drug, using conventional equipment available in most clinical laboratories. After chromatographic separation of the blood extract, the tacrolimus fraction is analyzed by an automated microparticle enzyme immunoassay (MEIA) performed on the IMx analyzer (Abbott Labs.). This method is linear from 0 to 40 micrograms/L, yields CVs from 8.5% to 18.2%, and has a detection limit of 5 micrograms/L. Tacrolimus concentrations obtained by HPLC-MEIA in hepatic and renal transplant patients are from 47.5% to 18.8% lower than those obtained by MEIA, according to liver function tests and metabolite accumulation, even though no significant differences were observed between the methods for drug-free blood samples supplemented with known amounts of tacrolimus.


2011 ◽  
pp. 238-261 ◽  
Author(s):  
G. Camps-Valls ◽  
J. D. Martin-Guerrero

Recently, important advances in dosage formulations, therapeutic drug monitoring (TDM), and the emerging role of combined therapies have resulted in a substantial improvement in patients’ quality of life. Nevertheless, the increasing amounts of collected data and the non-linear nature of the underlying pharmacokinetic processes justify the development of mathematical models capable of predicting concentrations of a given administered drug and then adjusting the optimal dosage. Physical models of drug absorption and distribution and Bayesian forecasting have been used to predict blood concentrations, but their performance is not optimal and has given rise to the appearance of neural and kernel methods that could improve it. In this chapter, we present a complete review of neural and kernel models for TDM. All presented methods are theoretically motivated, and illustrative examples in real clinical problems are included.


2005 ◽  
Vol 18 (6) ◽  
pp. 444-460 ◽  
Author(s):  
Michele Y. Splinter

Eight new antiepileptic drugs (AEDs) have been approved for use within the United States within the past decade. They are felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, and zonisamide. These afford clinicians with more options to increase efficacy and tolerability in the treatment of patients with epilepsy. Pharmacokinetic properties and drug interactions with other AEDs and other medications taken for comorbidities are individually discussed for each of these new agents. Drug concentrations are not routinely monitored for these newer agents, and there have been few studies designed to investigate their concentration-effect relationships. For most of these medications, the concentrations observed in responders and nonresponders overlap considerably and levels associated with efficacy are often associated with adverse events, complicating the definition of target ranges. Also, epilepsy manifests itself sporadically causing difficulty in clinically monitoring efficacy of medications. Therapeutic drug monitoring provides for the individualization of treatment for these agents, which is important because they demonstrate significant variability in inter- and intraindividual pharmaco-kinetic properties. Therapeutic drug monitoring also allows for identification of noncompliance, drug interactions, and toxicity. Current knowledge of the relationships between efficacy, toxicity, and drug concentrations is discussed.


2020 ◽  
Vol 14 (Supplement_1) ◽  
pp. S667-S668
Author(s):  
S Gleeson ◽  
K Sugrue ◽  
M Buckley ◽  
J McCarthy

Abstract Background Therapeutic drug monitoring (TDM) is the clinical practice of measuring serum drug concentrations to guide clinical decision making. Achieving therapeutic drug concentrations has been associated with clinical, endoscopic and histological outcomes in IBD. The use of TDM offers a more personalised treatment approach and is associated with sustained clinical remission. Proactive TDM was introduced to the Mercy University Hospital in 2014 for all patients on biologics. Methods One hundred patients receiving biologic infusion (Infliximab) were evaluated post induction (week 12) for therapeutic drug trough concentration and for clinical response. Serum samples were taken from all IBD patients at week 12. Biologic response assessment forms were complete for all patients to assess symptom improvement. Results Thirty-five per cent of patients had sub therapeutic trough levels at week 12. They subsequently received 3 increased doses of 10mgs/kg and levels were rechecked. Of these 90% achieved therapeutic levels after the dose escalation. 65% of patients had therapeutic levels at week 12. There was a correlation between therapeutic trough levels and patient reported improvement of clinical symptoms in 85% of respondents. Conclusion TDM in our unit facilitates appropriate dose 100 patients receiving biologic infusion (Infliximab) were evaluated post induction (week 12) for therapeutic drug trough concentration and for clinical response. Serum samples were taken from all IBD patients at week 12. Biologic response assessment forms were complete for all patients to assess symptom improvement.


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