The Role of Risk or Contributory Death Factors in Methadone-Related Fatalities: A Review and Pooled Analysis

Intoxications involving methoxyacetylfentanyl and U-47700: a study of 3 polydrug fatalities

Novel synthetic opioids (NSOs) represent an emerging group of novel psychoactive substances, acting as agonists at the opioid receptors. NSOs include fentanyl-related compounds, e.g. methoxyacetylfentanyl (MeACF), and non-fentanyl analogs, e.g. "U compounds" including U-47700. Here we present three cases of death involving MeACF and U-47700, with particular reference to preliminary data on pharmacokinetics and tissue distribution.After a complete post-mortem examination, general unknown screenings and analysis of drugs of abuse were performed on postmortem samples by immunoassays, gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. To quantify the analytes of interest in post-mortem blood and tissues, the standard addition method was used. A toxicological significance score (TSS), weighing the role of the NSO in each death case, was assigned.Case 1 died at the hospital after consumption of U-47700, methadone (serum levels: 2,600 ng/ml and 37 ng/ml), tilidine and benzodiazepines. In case 2, U-47700 (204 ng/ml) together with methadone (290 ng/ml), flubromazepam (480 ng/ml) and diazepam (300 ng/ml) were detected in peripheral blood. In case 3, methoxyacetylfentanyl (266 ng/ml), furanylfentanyl (4.3 ng/ml) 4-ANPP (15 ng/ml) and alprazolam (69 ng/ml) were quantified in femoral blood. In all cases, the NSO likely contributed to the death (TSS = 3).NSOs appear to be often consumed in the setting of polydrug intoxications, especially in combination with other opioids and benzodiazepines, which often exert synergistic effects. The standard addition method remains the most reliable in post-mortem analysis and toxicological results should always be evaluated together with circumstantial and autopsy data.

Methadone and buprenorphine-related deaths among people prescribed and not prescribed Opioid Agonist Therapy during the COVID-19 pandemic in England

BACKGROUND

The coronavirus pandemic resulted in many changes which had the potential to impact mortality related to opioid agonist therapy (OAT; methadone, buprenorphine), including changes in the prescribing and dispensing of OAT and patterns of drug availability and use. We aimed to assess the impact of the first lockdown (initiated March 23rd 2020) on methadone- and buprenorphine-related deaths in England in people both prescribed and not prescribed OAT using data from the National Programme on Substance Abuse Deaths.

METHODS

This was a retrospective post-mortem toxicology study of OAT-related deaths which occurred in the 3-month period March 23rd to June 22nd in the years 2016-2020. Provisional data regarding numbers accessing treatment for opioid use disorder was provided by the National Drug Treatment Monitoring System.

RESULTS

We found a 64% increase in methadone-related deaths in March to June 2020 compared to March to June 2019 (2019 n = 96; 2020 projected n = 157). There were increases in the mortality rate of both in-treatment decedents (22% increase; 2019 n = 45; an exponential smoothing model of the 2016-19 trend [α=0.5] predicted 44 deaths in 2020, 55 were reported) and decedents not prescribed methadone (74% increase; 2019 n = 46; 2016-19 trend predicted 43 deaths in 2020, 80 were reported). There was no increase in buprenorphine-related deaths (2019 n = 9/529; 2020 n = 11/566). There were no changes in the numbers of deaths where other opioids or multiple substances were detected, or in methadone levels detected. Numbers of people accessing treatment for opioid use disorder in 2020 did not decrease relative to previous years (p >0.05).

CONCLUSIONS

Methadone-related deaths in non-prescribed individuals, but not prescribed individuals, increased considerably above the annual trend forecast for 2020 during the first COVID-19 lockdown in England. Further studies are thus needed to understand this difference.

Infant urinary metabolomic profile in a fatal acute methadone intoxication

A case report suspicious for a Sudden Infant Death Syndrome is here described. Pathological findings were consistent with an acute respiratory failure while toxicological analysis revealed an elevated blood methadone concentration. Death was then ascribed to an acute methadone intoxication. In addition to the routinary approach, the urinary sample collected at autopsy was investigated with a ¹H NMR metabolomic approach and the identified metabolomic profile was challenged with the urinary metabolomic profiles previously obtained from 10 newborns who experienced perinatal asphyxia and 16 healthy control newborns. Intriguingly, the urinary profile of the methadone intoxicated infant was very similar to those belonging to the perinatal asphyxia newborns, especially to those belonging to the newborns characterised by the worst outcome. The results offer several hints on a shared metabolic derangement between different mechanisms of asphyxia/hypoxia. To the best of the authors’ knowledge, this is the first report of the use of a metabolomic approach in a pathological case, in which metabolomics offers useful additional information regarding the mechanism and the cause of death.