The optimization of methadone dosing whilst treating with rifampicin: A pharmacokinetic modeling study

Revolutionizing Precision Medicine: Exploring Wearable Sensors for Therapeutic Drug Monitoring and Personalized Therapy

Precision medicine, particularly therapeutic drug monitoring (TDM), is essential for optimizing drug dosage and minimizing toxicity. However, current TDM methods have limitations, including the need for skilled operators, patient discomfort, and the inability to monitor dynamic drug level changes. In recent years, wearable sensors have emerged as a promising solution for drug monitoring. These sensors offer real-time and continuous measurement of drug concentrations in biofluids, enabling personalized medicine and reducing the risk of toxicity. This review provides an overview of drugs detectable by wearable sensors and explores biosensing technologies that can enable drug monitoring in the future. It presents a comparative analysis of multiple biosensing technologies and evaluates their strengths and limitations for integration into wearable detection systems. The promising capabilities of wearable sensors for real-time and continuous drug monitoring offer revolutionary advancements in diagnostic tools, supporting personalized medicine and optimal therapeutic effects. Wearable sensors are poised to become essential components of healthcare systems, catering to the diverse needs of patients and reducing healthcare costs.

An Overview of Physiologically-Based Pharmacokinetic Models for Forensic Science

A physiologically-based pharmacokinetic (PBPK) model represents the structural components of the body with physiologically relevant compartments connected via blood flow rates described by mathematical equations to determine drug disposition. PBPK models are used in the pharmaceutical sector for drug development, precision medicine, and the chemical industry to predict safe levels of exposure during the registration of chemical substances. However, one area of application where PBPK models have been scarcely used is forensic science. In this review, we give an overview of PBPK models successfully developed for several illicit drugs and environmental chemicals that could be applied for forensic interpretation, highlighting the gaps, uncertainties, and limitations.

Management of Infective Endocarditis in People Who Inject Drugs: A Scientific Statement From the American Heart Association

BACKGROUND

The American Heart Association has sponsored both guidelines and scientific statements that address the diagnosis, management, and prevention of infective endocarditis. As a result of the unprecedented and increasing incidence of infective endocarditis cases among people who inject drugs, the American Heart Association sponsored this original scientific statement. It provides a more in-depth focus on the management of infective endocarditis among this unique population than what has been provided in prior American Heart Association infective endocarditis-related documents.

METHODS

A writing group was named and consisted of recognized experts in the fields of infectious diseases, cardiology, addiction medicine, and cardiovascular surgery in October 2021. A literature search was conducted in Embase on November 19, 2021, and multiple terms were used, with 1345 English-language articles identified after removal of duplicates.

CONCLUSIONS

Management of infective endocarditis in people who inject drugs is complex and requires a unique approach in all aspects of care. Clinicians must appreciate that it requires involvement of a variety of specialists and that consultation by addiction-trained clinicians is as important as that of more traditional members of the endocarditis team to improve infective endocarditis outcomes. Preventive measures are critical in people who inject drugs and are cured of an initial bout of infective endocarditis because they remain at extremely high risk for subsequent bouts of infective endocarditis, regardless of whether injection drug use is continued.

In vitro-in silico-based prediction of inter-individual and inter-ethnic variations in the dose-dependent cardiotoxicity of R- and S-methadone in humans

New approach methodologies predicting human cardiotoxicity are of interest to support or even replace in vivo-based drug safety testing. The present study presents an in vitro–in silico approach to predict the effect of inter-individual and inter-ethnic kinetic variations in the cardiotoxicity of R- and S-methadone in the Caucasian and the Chinese population. In vitro cardiotoxicity data, and metabolic data obtained from two approaches, using either individual human liver microsomes or recombinant cytochrome P450 enzymes (rCYPs), were integrated with physiologically based kinetic (PBK) models and Monte Carlo simulations to predict inter-individual and inter-ethnic variations in methadone-induced cardiotoxicity. Chemical specific adjustment factors were defined and used to derive dose–response curves for the sensitive individuals. Our simulations indicated that Chinese are more sensitive towards methadone-induced cardiotoxicity with Margin of Safety values being generally two-fold lower than those for Caucasians for both methadone enantiomers. Individual PBK models using microsomes and PBK models using rCYPs combined with Monte Carlo simulations predicted similar inter-individual and inter-ethnic variations in methadone-induced cardiotoxicity. The present study illustrates how inter-individual and inter-ethnic variations in cardiotoxicity can be predicted by combining in vitro toxicity and metabolic data, PBK modelling and Monte Carlo simulations. The novel methodology can be used to enhance cardiac safety evaluations and risk assessment of chemicals.

A review of pregnancy-induced changes in opioid pharmacokinetics, placental transfer, and fetal exposure: Towards fetomaternal physiologically-based pharmacokinetic modeling to improve the treatment of neonatal opioid withdrawal syndrome

Physiologically-based pharmacokinetic (PBPK) modeling has emerged as a useful tool to study pharmacokinetics (PK) in special populations, such as pregnant women, fetuses, and newborns, where practical hurdles severely limit the study of drug behavior. PK in pregnant women is variable and everchanging, differing greatly from that in their nonpregnant female and male counterparts typically enrolled in clinical trials. PBPK models can accommodate pregnancy-induced physiological and metabolic changes, thereby providing mechanistic insights into maternal drug disposition and fetal exposure. Fueled by the soaring opioid epidemic in the United States, opioid use during pregnancy continues to rise, leading to an increased incidence of neonatal opioid withdrawal syndrome (NOWS). The severity of NOWS is influenced by a complex interplay of extrinsic and intrinsic factors, and varies substantially between newborns, but the extent of prenatal opioid exposure is likely the primary driver. Fetomaternal PBPK modeling is an attractive approach to predict in utero opioid exposure. To facilitate the development of fetomaternal PBPK models of opioids, this review provides a detailed overview of pregnancy-induced changes affecting the PK of commonly used opioids during gestation. Moreover, the placental transfer of these opioids is described, along with their disposition in the fetus. Lastly, the implementation of these factors into PBPK models is discussed. Fetomaternal PBPK modeling of opioids is expected to provide improved insights in fetal opioid exposure, which allows for prediction of postnatal NOWS severity, thereby opening the way for precision postnatal treatment of these vulnerable infants.

Precision dosing of methadone during pregnancy: A pharmacokinetics virtual clinical trials study

BACKGROUND

Methadone use for the management of opioid dependency during pregnancy is commonplace. Methadone levels are altered during pregnancy due to changes in maternal physiology. Despite this, a paucity of data exist regarding the most appropriate optimal dosing regimens during pregnancy.

METHODS

This study applied a pharmacokinetic modeling approach to examine gestational changes in R- and S-methadone concentrations in maternal plasma and fetal (cord) blood. This study did so to derive a theoretical optimal dosing regimen during pregnancy, and to identify the impact of Cytochromes P450 (CYP) 2B6 and 2C19 polymorphisms on methadone maternal and fetal pharmacokinetics.

RESULTS

The study noted significant decreases in maternal R- and S-methadone plasma concentrations during gestation, with concomitant increases in fetal levels. At a dose of 90 mg once daily, 75% (R-) and 94% (S-) of maternal methadone trough levels were below the lower therapeutic window at term (week 40). The developed optimal dosing regimen escalated doses to 110 mg by week 5, followed by 10 mg increments every 5 weeks up to a maximum of 180 mg once daily near term. This increase resulted in 27% (R-) and 11% (S-) of subjects with trough levels below the lower therapeutic window at term. CYP2B6 poor metabolizers (PM) and either CYP2C19 extensive metabolizers (EM), PM, or ultra-rapid (UM) metabolizer phenotypes demonstrated statistically significant increases in concentrations when compared to their matched CYP2B6 EM counterparts.

CONCLUSIONS

Specific and gestation-dependent dose titrations are required during pregnancy to reduce the risks associated with illicit drug use and to maintain fetal safety.

Methadone for Pain Management: A Pharmacotherapeutic Review

Methadone is increasingly being used for its analgesic properties. Despite the increasing popularity, many healthcare providers are not familiar with methadone's complex pharmacology and best practices surrounding its use. The purpose of this narrative review article is to discuss the pharmacology of methadone, the evidence surrounding methadone's use in acute pain management and both chronic cancer and non-cancer pain settings, as well as highlight pertinent safety, monitoring, and opioid rotation considerations. Methadone has a unique mechanism of action when compared with all other opioids and for this reason methadone has come to hold a niche role in the management of opioid-induced hyperalgesia and central sensitization. Understanding of the mechanisms of variability in methadone disposition and drug interactions has evolved over the years, with the latest evidence revealing that CYP 2B6 is the major determinant of methadone elimination and plays a key role in methadone-related drug interactions. From an acute pain perspective, most studies evaluating the use of intraoperative intravenous methadone have reported lower pain scores and post-operative opioid requirements. Oral methadone is predominantly used as a second-line opioid treatment for select chronic pain conditions. As a result, several oral morphine to oral methadone conversion ratios have been proposed, as have methods in which to rotate to methadone. From an efficacy standpoint, limited literature exists regarding the effectiveness of methadone in the chronic pain setting with most of the available efficacy data pertaining to methadone's use in the treatment of cancer pain. Many of the prospective studies that exist feature low participant numbers. Few clinical trials investigating the role of methadone as an analgesic treatment are currently underway. The complicated pharmacokinetic properties of methadone and risks of harm associated with this drug highlight how critically important it is that healthcare providers understand these features before prescribing/dispensing methadone. Particular caution is required when converting patients from other opioids to methadone and for this reason only experienced healthcare providers should undertake such a task. Further randomized trials with larger sample sizes are needed to better define the effective and safe use of methadone for pain management.

Dalbavancin and telavancin in the treatment of infective endocarditis: a literature review

Glycopeptides have an established role in the management of infective endocarditis, and feature in current treatment guidelines. Newer lipoglycopeptide agents (dalbavancin, telavancin and oritavancin), which are analogues of glycopeptides with structural modifications giving rise to added novel mechanisms of antimicrobial activity, are approved for the treatment of Gram-positive skin and skin structure infections, and also for nosocomial pneumonia (only telavancin has approval for the latter indication). Recent evidence has also emerged to support their use in the treatment of bone and joint infections. This article reviews the current literature on dalbavancin and telavancin in the treatment of infective endocarditis, a condition for which the role of these agents is yet to be established.

Integrating in vitro data and physiologically based kinetic modeling-facilitated reverse dosimetry to predict human cardiotoxicity of methadone

Development of novel testing strategies to detect adverse human health effects is of interest to replace in vivo-based drug and chemical safety testing. The aim of the present study was to investigate whether physiologically based kinetic (PBK) modeling-facilitated conversion of in vitro toxicity data is an adequate approach to predict in vivo cardiotoxicity in humans. To enable evaluation of predictions made, methadone was selected as the model compound, being a compound for which data on both kinetics and cardiotoxicity in humans are available. A PBK model for methadone in humans was developed and evaluated against available kinetic data presenting an adequate match. Use of the developed PBK model to convert concentration–response curves for the effect of methadone on human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) in the so-called multi electrode array (MEA) assay resulted in predictions for in vivo dose–response curves for methadone-induced cardiotoxicity that matched the available in vivo data. The results also revealed differences in protein plasma binding of methadone to be a potential factor underlying variation between individuals with respect to sensitivity towards the cardiotoxic effects of methadone. The present study provides a proof-of-principle of using PBK modeling-based reverse dosimetry of in vitro data for the prediction of cardiotoxicity in humans, providing a novel testing strategy in cardiac safety studies.

Towards exhaustive electromembrane extraction under stagnant conditions

Electromembrane extraction (EME) in small, stagnant and chip-like devices has the potential for future in-field operation. Literature briefly discuss such systems, but performance suffered from evaporative losses of sample and acceptor. To address this, the current paper reports electromembrane extraction (EME) of five basic drugs (model analytes) from aqueous buffer solutions and whole blood samples under stagnant conditions in a completely closed system. A laboratory-made polyoxymethylene (POM) well plate served as compartment for the sample solution, while a commercially available well filter plate was used to immobilize 2-nitrophenyl octyl ether (NPOE) as supported liquid membrane (SLM) and as closed compartment for the acceptor solution. Major design parameters (sample compartment and electrode geometry) and operational parameters (sample volume, voltage and extraction time) were investigated and optimized. Electrode geometry was not very critical, but extraction efficiency increased with decreasing sample volume. Extraction from 50 μL aqueous buffer solution for 60 min and with a voltage of 75 V was considered exhaustive (sample was depleted), with recoveries ranging between 75% and 87% for loperamide, haloperidol, methadone, nortriptyline, and pethidine (RSD: 2-12%). Extraction from whole blood samples under optimized conditions yielded slightly lower recoveries, ranging between 57 and 96% (RSD: 3-12%). Stagnant EME was evaluated in combination with liquid chromatography-mass spectrometry (LC-MS) as a highly specific instrumental method, and provided evaluation data on methadone from blood samples in accordance with regulatory requirements (LOD: 0.4 ng/mL, LOQ: 1.4 ng/mL, RSD: 6-20%). This work has improved upon the design of stagnant EME, moving it further towards a viable in-field operation device.