Utilizing postmortem drug concentrations in mechanistic modeling and simulation of cardiac effects: a proof of concept study with methadone.

Methadone-related poisoning has been found to be the leading and increasing cause of death among intoxication cases in several countries. Aside from respiratory depression, methadone is known to cause QT-prolongation, which may lead to sudden cardiac death. Concentrations in heart tissue should be more accurate for estimating cardiotoxic effects. The aim of this study was to investigate whether the effect of methadone on the QT-interval could be simulated and whether the concentrations in heart tissues allowed for better prediction of the Bazett corrected QT-interval (QTcB). A predictive performance study was conducted using the simulation platform Cardiac Safety Simulator to mimic five literature studies using their described study conditions. Both free and total plasma and heart concentrations were investigated using two different in silico models: the O'Hara-Rudy (ORD) model and the 10 Tusscher (TNNP) model. The results showed that the QTcB of methadone was best predicted either with total plasma using the TNNP model or with free plasma using the ORD model. The ORD model was highly sensitive to the total heart concentrations, resulting in overprediction of the QTcB. The TNNP model also overpredicted the QTcB, but to a lesser degree than the ORD model. Furthermore, due to a low baseline QTcB, the ORD model underpredicted the QTcB for both the free plasma and free heart concentrations. In conclusion, it is possible to simulate the cardiac effects of methadone, yet several elements influence the approach uncertainty including but not limited to biophysically details model of cardiac electrophysiology, exposure data, and input parameters.

Exploring death scenes and circumstances in fatal opioid poisonings: Insights for preventive strategies using forensic autopsy cases in Western Denmark.

INTRODUCTION: Fatal opioid poisoning is a growing global issue. This study aims to describe circumstances surrounding fatal opioid poisonings by examining death scenes, demographics, and information from bystanders with the goal of informing prevention efforts. METHODS: We extracted data from the autopsy reports of 327 forensic autopsy cases with fatal poisoning involving methadone and/or morphine from 2013-2020. RESULTS: Fatal opioid poisonings occurred in both rural and urban areas. Death scene was the decedent's own home and a relative's or friend's home in 62% and 21%, respectively. The decedent died alone in 64% of the cases while other people were staying at the same address while death occurred in 30%. Decedents aged 15-34 years were more likely to die with other people staying at the same address than persons aged > 44 years (OR±SD: 2.3 ± 0.9, p = 0.005), and had lower postmortem blood methadone concentrations compared to persons > 34 years (Median [interquartile range]: 0.36 [0.23-0.62] vs 0.63 [0.28-1.2] mg/kg, p = 0.002). Female sex was more prevalent, and persons using illegal drugs were less prevalent in decedents aged > 44 years compared to those with age 15-44 years (29% vs 20%, p = 0.05% and 67% vs 89%, p < 0.001, respectively). Other psychoactive drugs were detected in 97% of decedents, mainly benzodiazepines (80%). CONCLUSIONS: Preventive strategies based on our findings include the need for harm reduction initiatives in both urban and rural areas, recognizing symptoms of fatal poisoning, and awareness of low tolerance among younger age groups. Urgent attention should be given to avoiding opioid use alone, particularly among older individuals, including women using prescribed opioids. Conveying the risks of polydrug use to all age groups is essential, especially co-use of sedative drugs.

Heart insufficiency after combination of verapamil and metoprolol: A fatal case report and literature review.

The combination of verapamil or diltiazem with beta-blockers should be avoided because of potentially profound adverse effects on AV (atrioventricular) nodal conduction, heart rate, or cardiac contractility. This effect is unpredictable but may be enhanced due to CYP2D6 poor metabolizer status which could be a special vulnerability factor.

Postmortem protein stability investigations of the human hepatic drug-metabolizing cytochrome P450 enzymes CYP1A2 and CYP3A4 using mass spectrometry.

Variability in expression and activity of hepatic drug-metabolizing cytochrome P450 (CYP) enzymes can play a causal role in fatal intoxication cases and is thus of forensic interest. We investigated the feasibility of LC-MS/MS based quantification and in vitro enzyme activity measurements of two major drug-metabolizing enzymes CYP1A2 and CYP3A4 in postmortem human liver microsomes (HLM). In autopsy cases (postmortem interval 24-36 h) we found CYP1A2 and CYP3A4 protein levels similar to that measured in a non-decayed reference HLM pool, whereas CYP1A2 and CYP3A4 enzyme activities were absent or severely decreased. Stability studies showed that CYP1A2 and CYP3A4 protein abundances were relatively stable in tissue stored in vitro for up to seven days at 4 °C. When tissue was stored for more than one day at 21 °C variable and case-specific decay patterns were observed, and CYP abundances declined especially after 3-4 days storage. Investigations of 50 autopsy cases revealed mean CYP1A2 and CYP3A4 levels of 49 and 47 pmol per mg HLM protein and inter-individual variabilities similar to those reported in other studies. This study supports postmortem quantification of CYP proteins in autopsy hepatic tissue by mass spectrometry. SIGNIFICANCE: This study indicates that MS-based detection of drug-metabolizing cytochrome P450 (CYP) proteins is achievable in postmortem hepatic tissue and that acceptable quantification data are obtainable but dependent on the storage conditions and postmortem sampling time. CYP abundance data could contribute to a conceivable way of assessing individual CYP activity phenotypes in a postmortem context.