Controversies and carfentanil: We have much to learn about the present state of opioid poisoning

Revive and Refuse: Capacity, Autonomy, and Refusal of Care After Opioid Overdose

Physicians generally recommend that patients resuscitated with naloxone after opioid overdose stay in the emergency department for a period of observation in order to prevent harm from delayed sequelae of opioid toxicity. Patients frequently refuse this period of observation despiteenefit to risk. Healthcare providers are thus confronted with the challenge of how best to protect the patient's interests while also respecting autonomy, including assessing whether the patient is making an autonomous choice to refuse care. Previous studies have shown that physicians have widely divergent approaches to navigating these conflicts. This paper reviews what is known about the effects of opioid use disorder on decision-making, and argues that some subset of these refusals are non-autonomous choices, even when patients appear to have decision making capacity. This conclusion has several implications for how physicians assess and respond to patients refusing medical recommendations after naloxone resuscitation.

Navigating Care Refusal and Noncompliance in Patients with Opioid Use Disorder

BACKGROUND

For many emergency physicians (EPs), deciding whether or not to allow a patient suffering the ill effects of opioid use to refuse care is the most frequent and fraught situation in which they encounter issues of decision-making capacity, informed refusal, and autonomy. Despite the frequency of this issue and the well-known impacts of opioid use disorder on decision-making, the medical ethics community has offered little targeted analysis or guidance regarding these situations.

DISCUSSION

As a result, EPs demonstrate significant variability in how they evaluate and respond to them, with highly divergent understandings and application of concepts such as decision-making capacity, informed consent, autonomy, legal repercussions, and strategies to resolve the clinical dilemma. In this paper, we seek to provide more clarity to this issue for the EPs.

CONCLUSIONS

Successfully navigating this issue requires that EPs understand the specific effects that opioid use disorder has on decision-making, and how that in turn bears on the ethical concepts of autonomy, capacity, and informed refusal. Understanding these concepts can lead to helpful strategies to resolve these commonly-encountered dilemmas.

Validation of a quantitative liquid chromatography/hybrid quadrupole-linear ion trap MS/MS method for carfentanil and caffeine in a live human epidermis model

RATIONALE

Carfentanil, an opioid 10K times more potent than morphine, has no licit clinical use. A powerful CNS depressant, it has been identified increasingly as the cause of overdose death in the United States. Because it is highly lipophilic, the law enforcement and medical communities have been concerned that responding personnel could be percutaneously exposed and that exposure could be enhanced with the use of alcohol-containing hand sanitizers. An LC-MS/MS method was developed to evaluate solvent effects on percutaneous absorption of carfentanil in a live human epidermal model.

METHODS

In this study, a quantitative liquid chromatography/hybrid triple quadrupole-linear ion trap method was developed for carfentanil and for caffeine, a molecule routinely used to monitor epidermal cell culture viability. The method employed reverse-phase liquid chromatography coupled with positive electrospray ionization and multiple reaction monitoring (MRM) to quantify carfentanil and caffeine against calibration curves formulated from authentic standards. Limits of detection (LOD) for the two compounds were determined using 10:1 signal-to-noise requirements for all product ions with relative peak areas within ±20% of those observed for a mid-level calibrator. Precision and accuracy were determined by analyzing positive controls formulated in quintuplicate, by a different analyst, at three concentrations bracketing the method dynamic range. Inter-day precision was evaluated using data collected from three separate days of analyses.

RESULTS

Calibration curves for seven formulated replicates of the two compounds met linearity requirements over at least four orders of magnitude concentration range. The accuracy of measured concentration results was within ±20% of the actual, precision across results (%CV) was ≤15%, curve coefficients of determination (r) were ≥0.980 (correlation coefficient r > 0.990), and relative ion ratios of all qualifier ions were within ±20% of those for a mid-level standard. Limits of quantification (LOQs) for carfentanil and caffeine were 230 pg/ml and 12 ng/ml, respectively. Intra-day accuracies (mean concentrations) for carfentanil and caffeine ranged from 90.1% to 100.8% and from 87.1% to 108.9%, respectively; inter-day accuracies ranged from 98.7% to 100.4% and from 97.5% to 101.7%, respectively. Intra-day precision (%CV) over the dynamic range ranged from 1.31 to 8.88 and from 1.49 to 6.72 for carfentanil and caffeine, respectively. Inter-day precision ranged from 4.7 to 9.9 %CV for carfentanil and 7.6-121 %CV for caffeine.

CONCLUSIONS

The method was used to evaluate the percutaneous absorption kinetics of carfentanil in solution as a function of solvent composition using an in vitro, live human epidermis model. Counterintuitively, as previously reported, the addition of organic solvents to the formulations decreased rather than increased the percutaneous absorption rate of the ultra-potent opioid, carfentanil.

Development of a Translational Model to Assess the Impact of Opioid Overdose and Naloxone Dosing on Respiratory Depression and Cardiac Arrest

In response to a surge of deaths from synthetic opioid overdoses, there have been increased efforts to distribute naloxone products in community settings. Prior research has assessed the effectiveness of naloxone in the hospital setting; however, it is challenging to assess naloxone dosing regimens in the community/first-responder setting, including reversal of respiratory depression effects of fentanyl and its derivatives (fentanyls). Here, we describe the development and validation of a mechanistic model that combines opioid mu receptor binding kinetics, opioid agonist and antagonist pharmacokinetics, and human respiratory and circulatory physiology, to evaluate naloxone dosing to reverse respiratory depression. Validation supports our model, which can quantitatively predict displacement of opioids by naloxone from opioid mu receptors in vitro, hypoxia-induced cardiac arrest in vivo, and opioid-induced respiratory depression in humans from different fentanyls. After validation, overdose simulations were performed with fentanyl and carfentanil followed by administration of different intramuscular naloxone products. Carfentanil induced more cardiac arrest events and was more difficult to reverse than fentanyl. Opioid receptor binding data indicated that carfentanil has substantially slower dissociation kinetics from the opioid receptor compared to 9 other fentanyls tested, which likely contributes to the difficulty in reversing carfentanil. Administration of the same dose of naloxone intramuscularly from 2 different naloxone products with different formulations resulted in differences in the number of virtual patients experiencing cardiac arrest. This work provides a robust framework to evaluate dosing regimens of opioid receptor antagonists to reverse opioid-induced respiratory depression, including those caused by newly emerging synthetic opioids.

Occupational Safety and Health and Illicit Opioids: State of the Research on Protecting Against the Threat of Occupational Exposure

The nationwide opioid crisis continues to affect not only people who use opioids but also communities at large by increasing the risk of accidental occupational exposure to illicit opioids. In addition, the emergence of highly potent synthetic opioids such as fentanyl and carfentanil increases the need to protect workers who may encounter unknown drug substances during job activities. To support the National Institute for Occupational Safety and Health Opioids Research Gaps Working Group, we examined the state of the literature concerning methods to protect workers against accidental occupational exposure to illicit opioids, and have identified unmet research needs concerning personal protective equipment, decontamination methods, and engineering controls. Additional studies are needed to overcome gaps in technical knowledge about personal protective equipment, decontamination, and control methods, and gaps in understanding how these measures are utilized by workers. Increasing our knowledge of how to protect against exposure to illicit opioids has the potential to improve occupational health across communities.

Gas Chromatography-Mass Spectrometry Analysis of Synthetic Opioids Belonging to the Fentanyl Class: A Review

The rising number of deaths caused by fentanyl overdosing in the US due to the overwhelming illicit use of this synthetic opioid has started a global campaign to develop efficient ways to control its production and distribution as well as discovering efficient antidotes to mitigate its lethal effects. Another important vein of focused research established by various agencies lies in the development of efficient and practical protocols for the detection of this opioid and analogs thereof in various matrices, whether environmental or biological in nature, particularly in the field of gas chromatography-mass spectrometry (GC-MS). The following review will cover the literature dealing with the detection and identification of synthetic opioids belonging to the fentanyl class by GC-MS means and hyphenated versions of the technique. Detailed descriptions will be given for the GC-MS methods employed for the analysis of the opioid, starting with the nature of the extraction protocol employed prior to analysis to the actual findings presented by the cited reports. Great effort has gone into describing the methods involved in each paper in a detailed manner and these have been compiled by year in tables at the end of each section for the reader's convenience. Lastly, the review will end with concluding remarks about the state of GC-MS analysis with regards to these powerful opioids and what lies ahead for this analytical field.

Pediatric opioid fatalities: What can we learn for prevention?

The aim of this study was to highlight 19 cases investigated by the North Carolina Office of the Chief Medical Examiner over the last 12 years involving accidental or undetermined manner of death opioid ingestions leading to fatalities in young children. These pediatric ingestions have closely mirrored the opioid epidemic in adults transitioning from prescription medications to illicit drugs including fentanyl and fentanyl analogues. Unlike a typical adult ingestion for purposes of self-harm or pleasure, poisonings in toddlers and infants are usually the result of curiosity, exploration, a decreased sense of danger, or imitation of adult or older sibling behavior. Eleven of the decedents were between the ages of 8 and 24 months. Among the cases were 12 prescription opioid exposure deaths and 7 illicit drug poisonings. A majority of the decedents were found unresponsive in an unkept home and/or in unsafe sleeping spaces with easy access to drugs or drug materials, which stresses the importance of safe pediatric sleeping conditions. After a complete pathological investigation, several of the cases had physical or scene evidence demonstrating that foil, plastic, or paper small enough to be ingested can contain enough potent opioid to cause death. Details from the toxicological investigation are included for each case to provide postmortem whole blood drug concentrations for forensic practitioners. Accidental pediatric poisonings are preventable. Risk reduction through improving awareness and education of the dangers of opioids is a key factor in mitigating these tragedies.

Percutaneous absorption of Carfentanil in vitro

Carfentanil is a synthetic opioid restricted to veterinary use due to its potency. Public health concerns have been raised as to the potential of carfentanil to exhibit toxicity after absorption via the percutaneous route following unintentional contamination. The current study measured the penetration of free base carfentanil through human, pig and rat skin using in vitro static diffusion cells. The human penetration rates were compared against literature toxicology values and indicated that, dependent on the contamination density, contamination area and residence time, skin decontamination and medical countermeasures may be required to ameliorate toxicity. The pig and rat skin penetration data will form the basis of future work to develop relevant in silico and in vivo models to further elucidate likely toxic effects and the medical strategies to mitigate against them.

The fentanyls: pharmacological and clinical aspects relevant to Australia

OBJECTIVE

North American and other jurisdictions have seen an alarming rise in the abuse of the fentanyls, with related overdose deaths. We sought to review this group of drugs to alert Australian psychiatrists and drug and alcohol clinicians to their clinical effects and potential harms.

CONCLUSIONS

The extreme potency of the fentanyls underlie their lethality. Vigilance and investment from both policy makers and health care providers are required to mitigate harm from a possible future Australian fentanyl epidemic.

Urine Drug Screens in the Emergency Department: The Best Test May Be No Test at All

The manuscript purpose is to provide a resource for clinicians on the functionality and pitfalls of the rapid urine drug screen for clinical decision making. Many providers remain under-informed about the inherent inaccuracies. The rapid urine drug screen is the first, and often only, step of drug testing. In the majority of emergency departments the urine drug screen is a collection of immunoassays reliant on an interaction between the structure of a particular drug or metabolite and an antibody. Drugs in separate pharmacologic classes often have enough structural similarity to cause false positives. Conversely, drugs within the same pharmacologic class often have different enough structures that they may result in inappropriate negatives. This lack of sensitivity and specificity significantly reduces the test utility, and may cause decision-making confusion. The timing of the drug screen relative to the drug exposure also limits accuracy, as does detection threshold. Confirmatory steps following the initial immunoassay include chromatography and/or mass spectrometry. These are unavailable at many institutions and results rarely return while the patient is in the emergency department. In addition, institutional capabilities vary, even with confirmatory testing. Confirmation accuracy depends on a number of factors, including the extent of the catalog of drugs/metabolites that the facility is calibrated to detect and report. In summary, the standard emergency department urine drug screen is a test with extremely limited clinical utility with multiple properties contributing to poor sensitivity, specificity, and accuracy. The test should be used rarely, if ever, for clinical decision making.

DARK Classics in Chemical Neuroscience: Carfentanil

Because of its remarkable potency and relative ease of synthesis, carfentanil (1) has recently emerged as a problematic contaminant in other drugs of abuse. Carfentanil and its close analogs, currently approved only for large animal veterinary medicine, have found use both as illicit additives to the clandestine manufacture of scheduled drugs and as chemical weapons. In this Review, the background, synthesis, manufacture, metabolism, pharmacology, approved indications, dosage, and adverse effects of carfentanil will be discussed along with its emergence as a key player in the ongoing opioid crisis.

How Emergency Physicians Approach Refusal of Observation after Naloxone Resuscitation

BACKGROUND

Patients who are resuscitated with naloxone frequently refuse a period of observation, even though they may be suffering from a variety of medical and psychiatric comorbidities. Emergency physicians (EPs) are then confronted with the challenge of how best to serve patients' interests while respecting autonomy.

OBJECTIVES

We sought to characterize how EPs think about this kind of dilemma and the strategies they use to resolve them.

METHODS

We conducted qualitative semi-structured interviews with a convenience sample of 59 emergency physicians attending the American College of Emergency Physicians' Scientific Assembly in October 2018. Three case vignettes highlighting different clinical and ethical features served as prompts. Interviews were analyzed using a constant comparative method to identify patterns of responses and derive key themes.

RESULTS

Across the vignettes, EPs demonstrated diverse approaches to observation, assessing decision-making capacity and encouraging compliance. Some EPs refused to comply with a patient's wishes even when they had determined a patient demonstrated capacity. Conversely, a few EPs were willing to allow patients to leave the emergency department (ED) without assessing capacity, or despite determining that the patient lacked capacity. Common reasons for complying with patients' demands were concerns about the patients' rights and concerns about the safety of staff. Most physicians interviewed reported no institutional guidelines or education on the topic, and many physicians expressed an interest in providing medication for addiction treatment in the ED.

CONCLUSIONS

EPs approach this clinical and ethical dilemma in widely divergent ways. Consensus about strategies for navigating patients' wishes relative to clinical concerns are needed to help EPs manage these challenging cases.

Novel synthetic opioids - toxicological aspects and analysis

Over the past few years, there has been an emerging number of new psychoactive drugs. These drugs are frequently mentioned as "legal highs", "herbal highs", "bath salts" and "research chemicals". They are mostly sold and advertised on online forums and on the dark web. The emerging new psychoactive substances are designed to mimic the effects of psychoactive groups, which are often abused drugs. Novel synthetic opioids are a new trend in this context and represent an alarming threat to public health. Given the wide number of fatalities related to these compounds reported within the last few years, it is an important task to accurately identify these compounds in biologic matrices in order to administer an effective treatment and reverse the respiratory depression caused by opioid related substances. Clinicians dealing with fentanyl intoxication cases should consider that it could, in fact, be a fentanyl analogue. For this reason, it is a helpful recommendation to include synthetic opioids in the routine toxicological screening procedures, including analysis in alternative matrices, if available, to investigate poly-drug use and possible tolerance to opioids. To address this public health problem, better international collaboration, effective legislation, effective investigation, control of suspicious "research chemicals" online forums and continuous community alertness are required. This article aims to review diverse reported fatalities associated with new synthetic opioids describing them in terms of pharmacology, metabolism, posology, available forms, as well as their toxic effects, highlighting the sample procedures and analytical techniques available for their detection and quantification in biological matrices.

Carfentanil: a narrative review of its pharmacology and public health concerns

Carfentanil is a synthetic fentanyl analogue approved for veterinary use. It is a mu-opioid receptor agonist with an estimated analgesic potency approximately 10,000 times that of morphine and 20-30 times that of fentanyl, based on animal studies. Since 2016, an increasing number of reports describe detection of carfentanil in the illicit drug supply. Little is known about the pharmacology of carfentanil in humans. Its high potency and presumed high lipophilicity, large volume of distribution, and potential active metabolites have raised concerns about the management of people exposed to carfentanil as well as the safety of first responders. Exposed individuals exhibit features of an opioid toxidrome and respond to opioid antagonists such as naloxone, although empiric dose requirements are unknown and very high doses may be required. Rare reports of suspected accidental poisoning of first responders have not been analytically confirmed and are unlikely to represent true poisoning. General occupational hygiene measures, including regular decontamination with soap and water, basic personal protective equipment (nitrile gloves, N95 mask, and eye goggles), and ready access to naloxone are generally sufficient in most circumstances.

Fentanyls and the safety of first responders: Science and recommendations

Opioids have many beneficial uses in medicine, but, taken inappropriately, they can cause life-threatening health effects. The increasing use of physician-prescribed and illicit opioids, including highly potent fentanyl and its analogs, have contributed to a significant increase in opioid-related drug overdoses in the United States, leading to a public health emergency. There have been a number of reports describing adverse health effects experienced by police officers, fire-fighter emergency medical services providers, and private sector ambulance personnel when responding to drug overdose incidents. Several sets of exposure prevention recommendations for first responders are available from government and the private sector. Understanding the scientific basis for these recommendations, increasing awareness by responders of the potential risks associated with opioid exposure during a response, and educating responders about safe work practices when exposure to opioids is suspected or confirmed are all critical prevention measures that can keep first responders safe.

The Pharmacokinetics and Pharmacodynamics of Carfentanil After Recreational Exposure: A Case Report

Carfentanil and related fentanyl analogs have been linked to a number of overdose deaths from drug users in several cities across North America. Diagnosis of carfentanil exposure requires a very high index of clinical suspicion, especially because available laboratory narcotic screens do not detect this agent. We describe a 34-year-old man admitted with depressed level of consciousness and in respiratory failure after recreational exposure to a white powder later inferred to contain carfentanil. Urine and whole blood samples were obtained for conventional preliminary drug screen immunoassays for unknown exposures, in addition to utilizing a high-pressure liquid chromatography-tandem mass spectrometry assay for quantification of carfentanil and its metabolite. The patient was intubated and required mechanically assisted ventilation for 31 hours until he was able to breathe safely on his own. Pharmacokinetic modeling of three timed blood samples identified the elimination half-life as 5.7 hours for carfentanil and 11.8 hours for the norcarfentanil metabolite. Awakening and breathing spontaneously corresponded to an interpolated blood carfentanil concentration of 0.52 ng/ml. This is the first pharmacokinetic and pharmacodynamic case report on the recreational use of carfentanil. Critical care clinicians should anticipate long periods of ventilatory support in the care of patients exposed to carfentanil.

Carfentanil and Current Opioid Trends in Summit County, Ohio

Introduction

The Summit County Medical Examiner's Office (SCMEO) observed 52 unexplained deaths during the month of July 2016 in which drug overdose was suspected. A fentanyl screening immunoassay performed on autopsy specimens was positive, but gas chromatograph/mass spectrometry (GC/MS) failed to confirm its presence. Carfentanil, a large wildlife tranquilizer, was later identified through reference lab testing as the cause of the sudden increase in overdoses.

Methods

Due to the large volume of cases which followed, a method for identifying carfentanil was developed utilizing in-house instrumentation. In addition, a retrospective analysis for all drug overdose cases was conducted through the SCMEO database from January 2009 through December 2016.

Results

Assessment of the data revealed a 277% increase in yearly overdose-related fatalities when comparing 2009 to 2016. Carfentanil was not identified in any other fatal drug overdoses in the area before the first appearance in Akron in July of 2016. There was an initial spike of 35 deaths in both July and August, which then decreased to 12 deaths in December. There was an almost equal distribution of carfentanil as a single agent and carfentanil mixed with multiple other illicit drugs.

Discussion

Current observations suggest carfentanil concentrations in overdose cases are decreasing; however, it may be present in combination with other drugs, especially other fentanyl analogs. The lower concentrations of carfentanil are much more difficult to detect in urine and peripheral blood, therefore making the testing of scene paraphernalia, central blood, and organ tissue more of a necessity.