Notes from the Field: Increased Incidence of Fentanyl-Related Deaths Involving Para-fluorofentanyl or Metonitazene - Knox County, Tennessee, November 2020-August 2021

Progress in the study of intestinal microbiota involved in morphine tolerance

Morphine is a widely used opioid for treatment of pain. The attendant problems including morphine tolerance and morphine dependence pose a major public health challenge. In recent years, there has been increasing interest in the gastrointestinal microbiota in many physiological and pathophysiological processes. The connectivity network between the gut microbiota and the brain is involved in multiple biological systems, and bidirectional communication between them is critical in gastrointestinal tract homeostasis, the central nervous system, and the microbial system. Many research have previously shown that morphine has a variety of effects on the gastrointestinal tract, but none have determined the function of intestinal microbiota in morphine tolerance. This study reviewed the mechanisms of morphine tolerance from the perspective of dysregulation of microbiota-gut-brain axis homeostasis, by summarizing the possible mechanisms originating from the gut that may affect morphine tolerance and the improvement of morphine tolerance through the gut microbiota.

In Support of Community Drug Checking Programs: Position Statement of AMERSA, Inc. (Association for Multidisciplinary Education and Research in Substance use and Addiction)

BACKGROUND

Position statements clarify key issues that are in alignment with the vision, mission, and values of the AMERSA, Inc. (Association for Multidisciplinary Education and Research in Substance use and Addiction). This Position Statement, endorsed by the AMERSA Board of Directors on October 3, 2023, amplifies the position of the organization, guides their activities, and informs the public and policymakers on the organization's stance on this issue.

ISSUE

The unregulated drug supply in the United States evolves constantly, leaving those who use drugs potentially unaware of new adulterants in their drugs. Not knowing that information can leave people vulnerable to serious adverse events such as fatal overdoses, wounds, and other health consequences. Without real-time data on the composition of drugs available in a community, healthcare providers and public health practitioners are left with insufficient data, making it increasingly difficult to know how to best serve people who use drugs. In this context, community-based drug checking has become recognized as an important harm reduction strategy with the potential to provide those who use drugs with more information about their supply.

RECOMMENDATIONS

It is imperative to expand funding and increase access to drug checking programs in communities across the United States. Key policy changes, such as those related to decriminalizing drug and drug paraphernalia possession, are needed to increase the utilization of drug checking programs. Protection of persons who use drugs through harm reduction strategies, including drug checking programs needs to be widely available and accessible.

Perceptions of COVID-19 risk during the pandemic: perspectives from people seeking medication for opioid use disorder

INTRODUCTION

The Coronavirus Disease 2019 (COVID-19) pandemic has had devastating consequences for persons with opioid use disorder (OUD). Yet, little is known about how people seeking treatment for OUD perceive the risks of COVID-19 and how their perception interplays with their health behaviours.

METHODS

In-depth interviews were conducted from September 2021 to March 2022 with 32 patients seeking medication treatment for OUD (MOUD) in Southern California. All interviews were conducted virtually and lasted between one and two hours. Interviews were recorded and transcribed verbatim. Two qualitative researchers independently conducted a content analysis of the transcripts to identify themes.

RESULTS

Three primary themes were identified: (1) perceptions and beliefs about COVID-19 susceptibility and severity; (2) perceptions of COVID-19 risk compared to substance use behaviours; and (3) vaccine hesitancy. Participants were mixed in their beliefs of susceptibility to contracting COVID-19 and the severity of the disease if contracted. Some participants reported taking precautions to mitigate their chances of acquiring COVID-19, and other participants reported that COVID was not a big concern as substance use took priority. For many of the participants, COVID-19 concerns were overshadowed by the risk of overdosing on substances and other risky substance use behaviour. Most of the participants (n = 23; 72%) had received at least one COVID-19 vaccine by the time of the interview, but over half (n = 19; 59%) expressed vaccine hesitancy. Vaccine hesitancy was driven by concerns about the unknown long-term side effects and potential interactions of the vaccine with MOUD.

CONCLUSIONS

Our study provides insight into COVID-19 prevention measures as well as vaccination perceptions and hesitancy among people who received treatment for OUD.Key messagesParticipants expressed diverse perceptions of the seriousness of COVID-19, with some taking precautions to mitigate their chances of acquiring COVID-19 and others perceiving that the risk of contracting COVID-19 was less than the risk of overdosing.Substance use, social isolation, vaccine hesitancy and COVID-19 risk behaviours should be studied as co-occurring phenomena that have potentially overlapping relationships that can influence behaviours that impact health and well-being.

Validation of an analytical method for quantitation of metonitazene and isotonitazene in plasma, blood, urine, liver and brain and application to authentic postmortem casework in New York City

Starting in 2019, an emerging class of novel opioids causing public health concern was benzimidazole opioids, also known as "nitazenes." Two nitazenes, isotonitazene and metonitazene, were detected in postmortem samples received at the New York City Office of Chief Medical Examiner. A protein precipitation extraction procedure was developed and validated for metonitazene and isotonitazene using 50 μL of blood, serum, liver, brain and urine utilizing liquid chromatography-tandem mass spectrometry. The limit of detection for both analytes was 0.10 ng/mL in plasma, blood and brain and 1.0 ng/mL for urine and liver. The developed method was applied to authentic casework in which isotonitazene was detected in 10 cases between 2021 and 2022, with femoral blood concentrations ranging from 0.11 to 12 ng/mL. Metonitazene was detected in four cases in 2022, with concentrations ranging from 0.10 to 1.5 ng/mL in femoral blood. All but one case had the presence of fentanyl and/or fentanyl analogs, and the next most commonly encountered analyte in these cases was xylazine. The manner of death was accidental for all cases with a detected nitazene, and all but one case was attributed to mixed drug intoxications. None of the cases reported the identified nitazene compound as the sole intoxicant responsible for death. The opioid crisis continues to tear apart communities throughout the world, including New York City. Continued research and communication regarding these drugs helps to fight this crisis.

Comparative toxicology of syringe exchange and postmortem blood samples in the District of Columbia: Trends and affinity analysis

This cross-sectional analysis aimed to understand the similarities and differences between drugs detected in syringes collected from syringe service providers in the District of Columbia and fatal overdose deaths captured by the State Unintentional Drug Overdose Reporting System. Substance exposures for these fatal and non-fatal drug use outcomes have not been previously compared. Substance distributions were examined and a paired significance test was used to compare changes over time. Affinity analysis was employed to reveal substance co-occurrences. Between September 2020 and September 2022, 1,118 postmortem blood samples (PBSs) and 3,646 syringes exchange samples (SESs) were processed, with fatal overdoses increasing 24.1%. Polysubstance use was more commonly found in postmortem blood (82.5%) than in syringe samples (48.6%). Of samples containing opioids, 94.8% of blood samples and 86.3% of syringes contained fentanyl, fentanyl analogs or fentanyl precursors/metabolites. PBSs had double the frequency of co-occurring stimulants and opioids (43.9%) as SESs (21.8%). Major changes in occurrence frequency over time were found for opioid and stimulant exposure in both groups, especially in the increased occurrence of fluorofentanyl (>400%), methamphetamine (>90%) and xylazine (>60%), while the incidence of fentanyl, heroin and metabolite morphine declined. These results indicate that while fatal use and syringe exchange populations have distinct substance exposures, which may contribute to differences in mortality rate, their substance distributions have similar change magnitudes. This study highlights the utility of using multiple data sources to provide a comprehensive description of drug use patterns and discusses the limitations in reporting data from each source.

Xylazine-involved fatal overdoses and localized geographic clustering: Cook County, IL, 2019-2022

BACKGROUND

Xylazine, a veterinary analgesic sedative, is circulating in the illicit drug markets of at least 23 states including Illinois. We conducted a geographic analysis to better identify the spatial distribution of xylazine-involved fatal overdoses in Cook County, IL.

METHODS

Cook County Medical Examiner Office's (CCMEO) publicly available data was used to identify xylazine-involved fatal overdoses from January 1, 2019, to June 30, 2022. Xylazine-positive (cases) to xylazine-negative groups with drug mixtures involving fentanyl, alcohol and stimulants (controls) were matched on age, race, sex, and year of death. Ripley's K-function was used to examine the likelihood of case clustering compared to controls with the Bernoulli spatial scan deployed to identify specific geographic clusters.

RESULTS

Almost all (94.4%) xylazine-positive overdoses contained fentanyl. Using coordinate-based matching, we found that approximately 3% of xylazine overdose incidents were co-located with other overdoses. Xylazine cases clustered to from 0 to 16.1 miles (max=10.6 miles). Results of the Bernoulli spatial scan varied by control group with two high-risk clusters found relative to alcohol and stimulants and a low-risk cluster relative to fentanyl. Differences in co-occurring drugs were found between xylazine and fentanyl groups like the absolute number of drugs (4.6v 3.4, p<0.0001) and fentanyl analog types.

CONCLUSIONS

Xylazine fatal overdose incident locations exhibited localized clustering relative to fentanyl overdoses but clusters were not precisely detected at these scales. Even so, our results, especially relative to repeat overdose micro "hot spots", offer insight on targeting harm reduction and other services at the neighborhood-level.

Old Drugs and New Challenges: A Narrative Review of Nitazenes

Nitazenes are a group of compounds developed in the 1950s as opioid analgesics, but they were never approved to market. As such, they are not well known outside of academic research laboratories. A characteristic of nitazenes is their high potency (e.g., hundreds to thousands fold more potent than morphine and other opioids and tenfold more potent than fentanyl). In the past few years, several nitazenes, including "designer analogs," have been detected in the illicit drug supply and have been implicated in overdose mortality, primarily due to their exceptionally high potency. In the street drug supply, nitazenes are often found mixed with fentanyl or other agents but their presence is not always disclosed to drug buyers, who may not even be familiar with nitazenes. These drugs pose a particular challenge since there is little experience in how to reverse a nitazene overdose or potential drug-drug or drug-alcohol interactions. Public health efforts are needed to better inform street drug consumers, first responders, healthcare professionals, and the general public about these "new old drugs" that are infiltrating the recreational drug supply.

Fentanyl analog structure-activity relationships demonstrate N-acyl chain length and aryl fluorine position as determinants of in vivo potency efficacy and safety

Opioid overdoses, particularly those involving fentanyl-related substances (FRS), present a significant public health challenge in the United States. This structure-activity relationship (SAR) study evaluated the relationship between the chemical structure of seventeen FRS and their in vivo mu-opioid-receptor (MOR) mediated effects. SAR evaluations included fluorine substitutions on the aniline or phenethyl ring and variations in N-acyl chain length. Adult male Swiss Webster mice were administered fluorinated regioisomers of fentanyl, butyrylfentantyl and valerylfentanyl, and compared to MOR standards including morphine, buprenorphine, and fentanyl to determine if they would elicit prototypical opioid-like effects including hyperlocomotion (open field test), antinociception (warm-water tail-withdrawal test), and hypoventilation (whole-body plethysmography test). To determine if the MOR was the pharmacological mechanism responsible for these effects, naltrexone or naloxone pretreatments were administered to evaluate their actions on FRS-induced antinociception and hypoventilation. There were three main findings. First, FRS elicited hyperlocomotion, antinociception, and hypoventilation in mice to varying degrees, similar to prototypical MOR standards. Second, the rank order of potencies for hypoventilatory effects of FRS with increasing N-acyl chain length (i.e., acetylfentanyl, fentanyl, butyrylfentanyl, valerylfentanyl, hexanoylfentanyl), phenethyl-fluorinated regioisomers (e.g., 2'-fluorofentanyl, 3'-fluorofentanyl, 4'-fluorofentanyl), and aniline-fluorinated regioisomers (e.g., ortho-fluorofentanyl, meta-fluorofentanyl, para-fluorofentanyl) were different for each series. Third, the degree of separation in potencies observed for the antinociceptive and hypoventilatory effects of these drugs did not always follow that which was observed for their antinociceptive and hyperlocomotor effects. This study of FRS establishes a SAR for in vivo MOR-mediated effects.

Proliferation of Novel Synthetic Opioids in Postmortem Investigations After Core-Structure Scheduling for Fentanyl-Related Substances

ABSTRACT

New generations of novel synthetic opioids (NSOs) have emerged to fill a void in the illicit drug markets left by the decline in popularity of fentanyl analogs subsequent to core-structure scheduling of fentanyl-related substances in the United States and China. These new opioids include members of the 2-benzyl benzimidazole (eg, isotonitazene, metonitazene, N -pyrrolidino etonitazene, protonitazene, etodesnitazene), benzimidazolone (eg, brorphine), and cinnamylpiperazine (eg, AP-238, 2-methyl AP-237) subclasses. Novel synthetic opioids continue to be detected in opioid-related fatal overdoses, demonstrating the harms associated with exposure to these drugs. Between January 2020 and December 2021, 384 casework blood samples were reported by our laboratory to contain 1 or more of the prior listed 8 NSOs. Isotonitazene (n = 144), metonitazene (n = 122), and brorphine (n = 91) were the 3 most prevalent substances, with positivity for isotonitazene and brorphine peaking just before the announcement of emergency scheduling. These NSOs have been documented as significant drivers of drug mortality, and this case series described here highlights the challenges medical examiners and coroners face in staying current with emerging drugs. Challenges include regional differences, rapid turnover, short lifecycles, variable toxicology testing, and difficulty in assessing individual drug toxicity in polydrug cases.