Collateral Damage: Neurological Correlates of Non-Fatal Overdose in the Era of Fentanyl-Xylazine

The effectiveness of the communities that HEAL intervention on reducing non-fatal opioid overdoses: A prespecified secondary analysis of a waitlist cluster control randomized controlled trial

INTRODUCTION

Along with a surge of opioid overdose deaths in the United States, the rates of nonfatal opioid overdose (NFOO) emergency department (ED) visits and hospitalizations have been sharply increasing.

METHODS

In the HEALing Communities Study (HCS), we conducted a pre-specified secondary analyses to evaluate the effectiveness of the Community that HEALS (CTH) intervention on reducing the count of NFOO ED visits and hospitalizations in a multi-site cluster randomized multi-site, two-arm, parallel, community-level, open, wait list-controlled trial study, Sixty-seven communities in Kentucky, Massachusetts, New York, and Ohio were randomized to the intervention (N = 34) or waitlist control condition (N = 33) stratified by state and balanced by urban/rural classification, fatal opioid overdose rate and population size of communities. We compared the rate of NFOO per 100,000 adults aged ≥18 years between intervention and control communities from July 1, 2021, to June 30, 2022. Rates were calculated in per 100,000 or per 100 adult population measured by inpatient and ED records for intervention community residents with an ICD-10-CM code for opioid poisoning.

RESULTS

Compared to control communities, intervention communities had 15 % fewer NFOO per capita (aRR = 0.85; 95 % CI = [0.74,0.96]; p-value=0.013). Effect modifications by state, urban/rural status, sex, age, race and ethnicity were not significant.

DISCUSSION

These findings suggest the intervention reduced NFOO ED visits and hospitalizations. The lack of effect modifications suggests that the intervention may be effective in a wide range of communities in the U.S. Further research is needed to identify the mechanisms through which the intervention reduces NFOO.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04111939.

The Rise of Fentanyl: Molecular Aspects and Forensic Investigations

Fentanyl is a synthetic opioid widely used for its potent analgesic effects in chronic pain management and intraoperative anesthesia. However, its high potency, low cost, and accessibility have also made it a significant drug of abuse, contributing to the global opioid epidemic. This review aims to provide an in-depth analysis of fentanyl's medical applications, pharmacokinetics, metabolism, and pharmacogenetics while examining its adverse effects and forensic implications. Special attention is given to its misuse, polydrug interactions, and the challenges in determining the cause of death in fentanyl-related fatalities. Fentanyl misuse has escalated dramatically, driven by its substitution for heroin and its availability through online platforms, including the dark web. Polydrug use, where fentanyl is combined with substances like xylazine, alcohol, benzodiazepines, or cocaine, exacerbates its toxicity and increases the risk of fatal outcomes. Fentanyl undergoes rapid distribution, metabolism by CYP3A4 into inactive metabolites, and renal excretion. Genetic polymorphisms in CYP3A4, OPRM1, and ABCB1 significantly influence individual responses to fentanyl, affecting its efficacy and potential for toxicity. Fentanyl's side effects include respiratory depression, cardiac arrhythmias, gastrointestinal dysfunction, and neurocognitive impairments. Chronic misuse disrupts brain function, contributes to mental health disorders, and poses risks for younger and older populations alike. Fentanyl-related deaths require comprehensive forensic investigations, including judicial inspections, autopsies, and toxicological analyses. Additionally, the co-administration of xylazine presents distinct challenges for the scientific community. Histological and immunohistochemical studies are essential for understanding organ-specific damage, while pharmacogenetic testing can identify individual susceptibilities. The growing prevalence of fentanyl abuse highlights the need for robust forensic protocols, advanced research into its pharmacogenetic variability, and strategies to mitigate its misuse. International collaboration, public education, and harm reduction measures are critical for addressing the fentanyl crisis effectively.

Synthetic opioids have disrupted conventional wisdom for treating opioid overdose

More than 90 % of opioid overdose deaths in North America are now caused by synthetic opioids, and while they are not as prevalent in the European illicit drug market, there are indications that they may become so in the near future. Multiple publications have argued that neither higher doses of naloxone nor more potent opioid receptor antagonists are needed to reverse a synthetic opioid overdose. However, the unique physicochemical properties of synthetic opioids result in a very rapid onset of respiratory depression compared to opium-based molecules, reducing the margin of opportunity to reverse an overdose. While intravenous administration rapidly delivers the high naloxone concentrations needed to reverse a synthetic opioid overdose, this option is often unavailable to first responders. A translational mechanistic model of opioid overdose developed by the FDA's Division of Applied Regulatory Science provides an unbiased approach to evaluate the effectiveness of overdose reversal strategies. Reports using this model demonstrated the naloxone tools (2 mg intramuscular and 4 mg intranasal) used by many first responders can result in an unacceptable loss of life following a synthetic opioid (fentanyl, carfentanil) overdose. Moreover, sequential (2.5 minutes between doses) administration of up to four doses of intranasal naloxone was no more effective at reducing the incidence of cardiac arrest (a surrogate endpoint for lethality) than a single dose, suggesting that attempts at titration may not provide the rapid absorption required to reverse a synthetic opioid overdose. This model was also used to compare the effectiveness of intranasal naloxone to intranasal nalmefene, a recently FDA-approved opioid receptor antagonist with a more rapid absorption and a higher affinity at mu-opioid receptors compared to intranasal naloxone. Intranasal nalmefene resulted in large and clinically meaningful reductions in the incidence of cardiac arrest compared to intranasal naloxone. Furthermore, simultaneous administration of four doses of intranasal naloxone was needed to reduce the incidence of cardiac arrest to levels approaching those produced by a single dose of intranasal nalmefene. These data are consistent with evidence that synthetics have indeed disrupted conventional wisdom in the treatment of opioid overdose.