Management of opioid analgesic overdose

Wartime toxicology: the spectre of chemical and radiological warfare in Ukraine

The unprovoked invasion of Ukraine by the Russian Federation has resulted in the largest humanitarian crisis in Europe since World War II. As fighting intensifies throughout Ukraine, there is an increasing concern that the Russian Federation may consider the direct use of chemical or radiological weapons against military personnel and civilians in Ukraine. Despite prohibition of chemical weapons from the Chemical Weapons Convention of 1997, recent evidence has demonstrated that state actors will continue to use these agents as weapons of war and terror, despite publicly denying their use. We review chemical weapons produced and used by the Russian Federation (or its allies) to identify plausible risks in the Russian war in Ukraine. We also provide rapid assessment and treatment guidelines to recognize and manage these acute exposures.

Evaluating the population-level effects of overdose prevention sites and supervised consumption sites in British Columbia, Canada: Controlled interrupted time series

BACKGROUND

On 14 April 2016, British Columbia's Provincial Medical Health Officer declared the overdose crisis a public health emergency, sanctioning the implementation of new overdose prevention sites (OPS) and supervised consumption sites (SCS) across the province.

METHODS

We used the BC Centre for Disease Control's Provincial Overdose Cohort of all overdose events between 1 January 2015 and 31 December 2017 to evaluate the population-level effects of OPSs and SCSs on acute health service use and mortality. We matched local health areas (LHA) that implemented any site with propensity score matched controls and conducted controlled interrupted time series analysis.

RESULTS

During the study period, twenty-five OPSs and SCSs opened across fourteen of British Columbia's 89 LHAs. Results from analysis of LHAs with matched controls (i.e. excluding Vancouver DTES) were mixed. Significant declines in reported overdose events, paramedic attendance, and emergency department visits were observed. However, there were no changes to trends in monthly hospitalization or mortality rates. Extensive sensitivity analyses found these results persisted.

CONCLUSIONS

We found OPSs and SCSs reduce opioid-related paramedic attendance and emergency department visit rates but no evidence that they reduce local hospitalization or mortality rates.

Pharmacokinetic considerations for community-based dosing of nasal naloxone in opioid overdose in adults

INTRODUCTION

The administration of the opioid antagonist naloxone in the community is a measure to prevent death from opioid overdose. Approved nasal naloxone sprays deliver initial doses of 0.9 to 8 mg. The level of the initial community dose is controversial, as the scientific base is weak.In this review knowledge of the pharmacokinetics of nasal, both approved and improvised nasal sprays, and intramuscular naloxone will be utilized to evaluate dose-effect relationships in previous studies of opioid overdose outcomes.

AREAS COVERED

The aim was to present scientifically based considerations on the initial nasal naloxone doses currently available, which reasonably balances the effect and adverse outcomes, given that at least two doses are at hand. Also included in these considerations is the challenge by illicitly manufactured fentanyl and analogs.This paper is based on both peer-reviewed and grey literature identified by several searches, of such as naloxone pharmacokinetics/formulations/outcomes/emergency medical services, in PubMed and Embase.

EXPERT OPINION

There is little scientific evidence that supports the use of initial systemic dosing that exceeds 0.8 mg in the community. Higher doses increase the risk of withdrawal symptoms feared in people who use opioids. Many obstacles may reduce the potential of community-administered naloxone.

Exposure to immediate-release tramadol in children 6 years and under - a nationwide French poison control center study

INTRODUCTION

Data regarding immediate-release (IR)-tramadol exposures in children remain sparse. We aimed to investigate the incidence of IR-tramadol exposures in ≤6-year-old children, to describe the characteristics and resulting outcome of ingestions involving IR-tramadol alone, and to estimate a clinically relevant toxic dose in this population.

METHODS

Retrospective analysis of IR-tramadol exposures in ≤6-year-old children, collected by the French Poison Control Centers (PCCs) in 2003-2019. The incidence was estimated using IR-tramadol prescription data from the Health Improvement Network database (the French version of THIN). The Poison severity score (PSS) was used to grade severity.

RESULTS

We found 1260 IR-tramadol exposures in ≤6-year-old children. The number of cases per 100,000 IR-tramadol-treated patients increased over time (p < .0001). One hundred forty-five cases involving IR-tramadol alone were analyzed. The median age was 3.0 years (IQR: 1.9, 4.0), the M/F ratio was 1.5 and the median dose was 5.0 mg/kg (IQR 3.3-11.1). Half of the children (49.7%) remained asymptomatic (PSS0) while 29.6% and 14.5% developed minor (PSS1) or moderate-to-severe (PSS2-PSS3) neurological symptoms, respectively. Twelve children developed respiratory depression. No seizures and no fatality were reported. All symptomatic children recovered within 24 h. The ingested IR-tramadol dose was positively correlated with the PSS (p < .0001). Using a receiver operating characteristic (ROC) curve approach (area under the curve, 0.92; p < .001), ingestion of ≥7.4 mg/kg IR-tramadol was appropriate to recommend hospital referral (sensitivity, 100% [95% confidence interval (CI), 85-100]; specificity, 73% [95% CI, 64-80]; predictive positive value, 39% [95% CI, 35-57]; negative predictive value, 100% [95% CI, 96-100]). Children who ingested <7.4 mg/kg IR-tramadol developed no (n = 68) or minor (n = 22) neurological symptoms.

CONCLUSIONS

Despite increasing tramadol prescriptions in adults during the study period in France, oral exposure to IR-tramadol in ≤6-year-old children was rare but possibly responsible for severe toxicity. Children with no underlying disease and concomitant medication ingesting <7.4 mg/kg IR-tramadol alone could be observed at home. However, given the observed variability in the onset of seizures after tramadol ingestion, which can occur at ingested tramadol doses below 7.4 mg and even at therapeutic doses, parents or guardians should be specifically warned about the risk of seizures.

Prevalences of and characteristics associated with single- and polydrug-involved U.S. Emergency Department Visits in 2018

INTRODUCTION

Nonfatal and fatal drug overdoses have recently increased. There are limited data describing the range of illicit, prescribed, and over-the-counter drugs involved in overdoses presenting to U.S. emergency departments (EDs).

METHODS

Using 2018 Healthcare Cost and Utilization Project (HCUP) Nationwide ED Sample (NEDS) data, we calculated weighted counts and percentages by drug among overdose-related ED visits. Overdose-related ED visits were those having an International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) drug poisoning code falling under parent codes T36-T50 (codes involving alcohol were not explicitly queried). We identified the top 30 mutually exclusive polydrug combinations and compared characteristics of visits by polydrug status.

RESULTS

In 2018, 908,234 ED visits had a T36-T50 drug poisoning code. The most frequently reported drugs involved were opioids (30.3% of visits; heroin: 15.2%), benzodiazepines (11.0%), stimulants (7.9%), other/unspecified antidepressants (7.1%), 4-aminophenol derivatives (6.6%), and other/unspecified drugs, medicaments, and biological substances (11.8%). Overdose was uncommon for most other drug classes (e.g., antibiotics). Polydrug visits were more likely to involve females (prevalence ratio [PR]: 1.14, 95% confidence interval [CI]: 1.12-1.16), be coded intentional self-harm (PR: 1.81, 95% CI: 1.77-1.85), and result in hospitalization (PR: 1.84, 95% CI: 1.79-1.89) or death (PR: 1.37, 95% CI: 1.22-1.53) compared to single-drug overdose-related visits. Benzodiazepines, opioids, and/or stimulants were most frequently involved in polydrug overdoses.

CONCLUSION

Opioids, benzodiazepines, and stimulants were most commonly reported in both single-drug and polydrug overdose-involved ED visits. Other drugs involved in overdoses included antidepressants and 4-aminophenol derivatives. Jurisdictions can use data on drugs involved in overdoses to better tailor prevention strategies to emerging needs.

Naloxone and nalmefene absorption delivered by hollow microneedles compared to intramuscular injection

Naloxone and nalmefene were administered to seven research beagle dogs (mean weight approximately 12 kg) at doses of 0.04 mg/kg and 0.014 mg/kg for naloxone and nalmefene, respectively. Each dose was administered intramuscularly (IM) with a standard IM injection and with a hollow microneedle device array using needles of 1 mm in length. The IM injection was delivered in the epaxial muscles, and the microneedle injection was delivered in the skin over the shoulder of each dog. Each dog received the same injections in a crossover design. Following the injection, blood samples were collected for plasma analysis of naloxone and nalmefene by high-pressure liquid chromatography with mass spectrometry detection (LCMS). The plasma sample concentrations were plotted for observed patterns of absorption and analyzed with non-compartmental pharmacokinetic methods (NCA). The results showed that the injection of naloxone from the microneedle device produced a higher peak concentration (CMAX) by 2.15 × compared the IM injection of the same dose, and time to peak concentration (TMAX) was similar. For the nalmefene injection, the peak was not as high (lower CMAX) by 0.94 × for the microneedle injection compared to the IM injection of the same dose. The microneedle produced an exposure, measured by area under the curve (AUC), that was 0.85 × and 0.58 × as high for naloxone and nalmefene, respectively, than the injection by the IM route. We also observed that although the dose for naloxone was approximately 3 × higher for naloxone compared to nalmefene, the mean peak concentration achieved from the naloxone injection was more than 12 × higher than that from the nalmefene injection. These studies were designed to test the feasibility of using the hollow microneedle array as an effective method of naloxone and nalmefene delivery for emergency treatment of opioid-induced respiratory depression (OIRD). The results of these studies will form the basis of future studies, using the dog as a model, for development of hollow microneedle microarray devices to deliver opioid antagonists for treatment of OIRD in people.

Opioid use disorder and the brain: a clinical perspective

Opioid use disorder (OUD) has gained increasing publicity and interest during recent years, with many countries describing problems of epidemic proportions with regard to opioid use and deaths related to opioids. While opioids are not themselves acutely neurotoxic, the chronic relapsing and remitting nature of this disorder means that individuals are often exposed to exogenous opioids for lengthy periods of time (either illicit or prescribed as treatment). We are increasingly characterizing the effect of such long-term opioid exposure on the brain. This narrative review aims to summarize the literature regarding OUD and the brain from a clinical perspective. Alterations of brain structure and function are discussed, as well as neurological and psychiatric disorders in OUD. Finally, we review current and new directions for assessment and treatment.

Time-Series Analysis of Fentanyl Concentration in the Unregulated Opioid Drug Supply in a Canadian Setting

North America has been contending with an unregulated street drug supply in which opioids are often adulterated with illicitly manufactured fentanyl. The unpredictability of composition may result in an increased risk of overdose due to unexpected elevated concentrations of the high-potency drug. Using data from a community-based drug-checking project, we evaluated trends in fentanyl concentration of illicit opioids in the context of an overdose epidemic. Using a quantification model for fentanyl hydrochloride, historical Fourier-transform infrared spectra from opioid drug-checking samples were analyzed to determine fentanyl concentrations. Median monthly fentanyl concentrations were plotted, and polynomial and autoregressive time-series analyses were performed to examine trends over time. A total of 3,621 fentanyl-positive samples were included in the study, spanning November 2017 to December 2019. Monthly median fentanyl concentrations ranged from 4.5% to 10.4%. Time-series analyses indicated that a third-degree polynomial model fit the data well (R2 = 0.639), suggesting a cyclical pattern in median concentration over time. Notably, absolute variance in fentanyl concentration decreased by an average 0.1% per month (P < 0.001). Future research should explore the relationship between fentanyl concentration and overdose to identify potential targeted harm-reduction interventions that can respond to changes in observed fentanyl concentration.

Perspectives of Stakeholders of Equitable Access to Community Naloxone Programs: A Literature Review

The purpose of this review is to examine the existing literature about facilitators and barriers influencing equitable access to naloxone programs by individuals who use opioids. A total of 49 published articles were examined, which generated four overarching themes:(1) Stigma as a barrier to access; (2) Lack of a wide range of stakeholder perspectives; (3) Need for a comprehensive understanding of factors affecting equitable access to naloxone programs; (4) Facilitators to increase the access of community naloxone programs. Our review highlighted the importance of advocacy in practice, education, administration, and policy to address the health inequities that exist in naloxone distribution programs. Advocacy activities involve the need for health care professionals to engage in social justice practice through evidence-based informed research about the facts of opioid use; challenging the stigma toward victim-blaming against naloxone users; as well as promoting program development and health policy to bring about equitable access to naloxone programs by marginalized and socially disadvantaged populations.

The emerging therapeutic role of some pharmacological antidotes in management of COVID-19

Background

A novel RNA coronavirus was identified in January 2020 as the cause of a pneumonia epidemic affecting the city of Wuhan; it rapidly spread across China.

Aim of the review

The aim is to discuss the potential efficacy of some pharmacologically known pharmacological antidotes (N-acetylcysteine; hyperbaric oxygen; deferoxamine; low-dose naloxone) for the management of COVID-19-associated symptoms and complications.

Method

An extensive search was accomplished in Medline, Embase, Scopus, Web of Science, and Central databases until the end of April, 2021. Four independent researchers completed the screening, and finally, the associated studies were involved.

Conclusion

The current proof hinders the experts for suggesting the proper pharmacological lines of treatment of COVID-19. Organizations, for example, WHO, should pursue more practical actions and design well-planned clinical trials so that their results may be used in the treatment of future outbreaks.

The pathophysiology of opioid-induced respiratory depression

Opiates, such as morphine, and synthetic opioids, such as fentanyl, constitute a class of drugs acting on opioid receptors which have been used therapeutically and recreationally for centuries. Opioid drugs have strong analgesic properties and are used to treat moderate to severe pain, but also present side effects including opioid dependence, tolerance, addiction, and respiratory depression, which can lead to lethal overdose if not treated. This chapter explores the pathophysiology, the neural circuits, and the cellular mechanisms underlying opioid-induced respiratory depression and provides a translational perspective of the most recent research. The pathophysiology discussed includes the effects of opioid drugs on the respiratory system in patients, as well as the animal models used to identify underlying mechanisms. Using a combination of gene editing and pharmacology, the neural circuits and molecular pathways mediating neuronal inhibition by opioids are examined. By using pharmacology and neuroscience approaches, new therapies to prevent or reverse respiratory depression by opioid drugs have been identified and are currently being developed. Considering the health and economic burden associated with the current opioid epidemic, innovative research is needed to better understand the side effects of opioid drugs and to discover new therapeutic solutions to reduce the incidence of lethal overdoses.

Google Trends Data: A Potential New Tool for Monitoring the Opioid Crisis

INTRODUCTION

There is a need to strengthen the standard surveillance of the opioid overdose crisis in the USA. The role of Google Trends (GT) was explored in this context.

METHODS

In this study, a systemic GT search was done for a period from January 2004 to December 2018. "Naloxone" and "drug overdose" were chosen as search inputs. By using locally weighted scatterplot smoothing, we locally regressed and smoothed the relative search data generated by the GT search. We conducted a changepoint analysis (CPA) to detect significant statistical changes in the "naloxone" trend from 2004 to 2018. Cross-correlation function analyses were done to examine the correlation between 2 time series: year-wise relative search volume (RSV) for "naloxone" and "drug overdose" with the age-adjusted drug overdose mortality rate. Pearson's correlation was performed for the state-wise age-adjusted mortality rate due to drug overdose and RSV for "naloxone" and "drug overdose."

RESULTS

Smoothed and regressed GT of "naloxone" were similar to the "opioid overdose" trend published by the National Center for Health Statistics. The CPA showed 2 statistically significant points in 2011 and 2015. CPA of year-wise RSV for "naloxone" and "drug overdose" showed significantly positive correlation with the age-adjusted drug overdose mortality at lag zero. State-wise RSV for "naloxone" and "drug overdose" too showed a strong and significant positive correlation with the state-wise mortality data.

DISCUSSION/CONCLUSION

Inexpensive, publicly accessible, real-time GT data could supplement and strengthen the monitoring of opioid overdose epidemic if used in conjunction with the existing official data sources.

In Vitro and In Vivo Analysis of Fentanyl and Fentalog Metabolites using Hyphenated Chromatographic Techniques: A Review

Fentanyl and fentanyl analogues (also called fentalogs) are used as medical prescriptions to treat pain for a long time. Apart from their pharmaceutical applications, they are misused immensely, causing the opioid crisis. Fentanyl and its analogues are produced in clandestine laboratories and sold over dark Web markets to different parts of the world, leading to a rise in the death rate due to drug overdose. This is because the users are unaware of the lethal effects of the newer forms of fentalogs. Unlike other drugs, these fentalogs cannot be detected easily, as very little data are available, and this is one of the major reasons for the risk of life-threatening poisoning or deaths. Hence, rigorous studies of these drugs and their possible metabolites are required. It is also necessary to develop techniques for the detection of minute traces of metabolites in biological fluids. This Review provides an overview of the application of hyphenated chromatographic techniques used to analyze multiple novel fentalogs, using in vivo and in vitro methods. The article focuses on the metabolites formed in phase I and phase II processes in biological specimens obtained in recent cases of drug abuse and overdose deaths that could be useful for the detection and differentiation of multiple fentalogs.

Immunomodifying and neuroprotective effects of noscapine: Implications for multiple sclerosis, neurodegenerative, and psychiatric disorders

Noscapine is a phthalide isoquinoline alkaloid with antitussive activity. Noscapine protects oligodendroglia from ischemic and chemical injury, binds to bitter taste receptors, antagonizes the bradykinin and histaminergic systems, which may be of benefit in treatment of multiple sclerosis. Noscapine normalizes axonal transport and exerts significant therapeutic efficacy in animal models of Parkinson's Disease and Amyotrophic Lateral Sclerosis. Noscapine exerts neuroprotective effects on oxygen- and glucose-deprived fetal cortical neuronal cells and reduces ischemic brain damage in neonatal rat pups. Pilot clinical studies indicated some beneficial effects of noscapine in stroke. Noscapine harbours anxiolytic activity and methyl-noscapine blocks small conductance SK channels, which is beneficial in alleviating anxiety and depression. Noscapine exerts anticholinesterase activity and acts inhibitory on the inflammatory transcription factor NF-κB, which may be harnessed in treatment of Alzheimer's Disease. With its blood-brain barrier traversing features and versatile actions, noscapine may be a promising agent in the armamentarium against neurodegenerative and psychiatric diseases.

Hypoxia driven opioid targeted automated device for overdose rescue

Opioid use disorder has been designated a worsening epidemic with over 100,000 deaths due to opioid overdoses recorded in 2021 alone. Unintentional deaths due to opioid overdoses have continued to rise inexorably. While opioid overdose antidotes such as naloxone, and nalmefene are available, these must be administered within a critical time window to be effective. Unfortunately, opioid-overdoses may occur in the absence of antidote, or may be unwitnessed, and the rapid onset of cognitive impairment and unconsciousness, which frequently accompany an overdose may render self-administration of an antidote impossible. Thus, many lives are lost because: (1) an opioid overdose is not anticipated (i.e., monitored/detected), and (2) antidote is either not present, and/or not administered within the critical frame of effectiveness. Currently lacking is a non-invasive means of automatically detecting, reporting, and treating such overdoses. To address this problem, we have designed a wearable, on-demand system that comprises a safe, compact, non-invasive device which can monitor, and effectively deliver an antidote without human intervention, and report the opioid overdose event. A novel feature of our device is a needle-stow chamber that stores needles in a sterile state and inserts needles into tissue only when drug delivery is needed. The system uses a microcontroller which continuously monitors respiratory status as assessed by reflex pulse oximetry. When the oximeter detects the wearer’s percentage of hemoglobin saturated with oxygen to be less than or equal to 90%, which is an indication of impending respiratory failure in otherwise healthy individuals, the microcontroller initiates a sequence of events that simultaneously results in the subcutaneous administration of opioid antidote, nalmefene, and transmission of a GPS-trackable 911 alert. The device is compact (4 × 3 × 3 cm), adhesively attaches to the skin, and can be conveniently worn on the arm. Furthermore, this device permits a centralized remotely accessible system for effective institutional, large-scale intervention. Most importantly, this device has the potential for saving lives that are currently being lost to an alarmingly increasing epidemic.

Naloxone dispensing among the commercially insured population in the United States from 2015 to 2018

The Centers for Disease Control and Prevention's (CDC) Guideline for Prescribing Opioids for Chronic Pain recommends that providers consider co-prescribing naloxone when factors that increase the risk of overdose are present. Naloxone is an opioid receptor antagonist that counteracts the effects of an opioid overdose. This paper explores trends in naloxone dispensing and out-of-pocket costs among commercially insured individuals in the United States. Administrative claims data from the IBM Watson Health MarketScan database are analyzed to assess trends in naloxone dispensing from 2015 to 2018. Descriptive statistics on concurrent dispensing of naloxone with opioid analgesics are performed among several at-risk populations. The rate of commercially insured individuals being co-dispensed naloxone increased between 2015 and 2018 across all population sub-groups. In 2018, 16.2 individuals were co-dispensed naloxone for every 1000 receiving an opioid dosage ≥ 90 MME/day compared to 0.9 in 2015, 27.6 individuals were co-dispensed naloxone for every 1000 concurrently dispensed benzodiazepines and an opioid dosage ≥ 90 MME/day compared to 7.6 in 2015, and 43.7 individuals were co-dispensed naloxone for every 1000 receiving an opioid dosage ≥90 MME/day with a past overdose compared to 17.6 in 2015. Median out-of-pocket cost for naloxone increased from $12 in 2015 to $25 in 2018. Despite increases in naloxone dispensing from 2015 to 2018, the provision of naloxone to the commercially insured population remains low. Opportunities remain to increase the supply of naloxone to at-risk populations. Considering ways to reduce out-of-pocket costs associated with naloxone may be a potential strategy to increase access to this life-saving drug.

Wearable biosensors have the potential to monitor physiological changes associated with opioid overdose among people who use drugs: A proof-of-concept study in a real-world setting

INTRODUCTION

Wearable biosensors have the potential to monitor physiological change associated with opioid overdose among people who use drugs.

METHODS

We enrolled 16 individuals who reported ≥ 4 daily opioid use events within the previous 30 day. Each was assigned a wearable biosensor that measured respiratory rate (RR) and actigraphy every 15 s for 5 days and also completed a daily interview assessing drug use. We describe the volume of RR data collected, how it varied by participant characteristics and drug use over time using repeated measures one-way ANOVA, episodes of acute respiratory depression (≤5 breaths/minute), and self-reported overdose experiences.

RESULTS

We captured 1626.4 h of RR data, an average of 21.7 daily hours/participant over follow-up. Individuals with longer injection careers and those engaging in polydrug use captured significantly fewer total hours of respiratory data over follow-up compared to those with shorter injections careers (94.7 vs. 119.9 h, p = 0.04) and injecting fentanyl exclusively (98.7 vs. 119.5 h, p = 0.008), respectively. There were 385 drug use events reported over follow-up. There were no episodes of acute respiratory depression which corresponded with participant reports of overdose experiences.

DISCUSSION

Our preliminary findings suggest that using a wearable biosensor to monitor physiological changes associated with opioid use was feasible. However, more sensitive biosensors that facilitate triangulation of multiple physiological data points and larger studies of longer duration are needed.

Evaluation of Basic Life Support First Responder Naloxone Administration Protocol Adherence

Objectives: Opioid overdoses have become a significant problem across the United States resulting in respiratory depression and risk of death. Basic Life Support (BLS) first responders have had the option to treat respiratory depression using a bag-valve-mask device, however naloxone, an opioid antagonist, has been shown to quickly restore normal respiration. Since the introduction of naloxone and recent mandates across many states for BLS personnel to carry and administer naloxone, investigation into the adherence of naloxone use standing protocols is warranted.

Methods: This preliminary study examined 100 initial cases of BLS first responder administration of naloxone for appropriate indications and protocol adherence.

Results: This study found that n=22/100 naloxone administrations were inappropriate, often given to patients who were not suffering from respiratory depression (n=11/22). Positive pressure ventilation (PPV) was not administered prior to naloxone in n=56/100 cases, of which n=42/100 had an inadequate respiratory effort documented. For patients with a known history of substance use disorder, there was a significant increase in administration of naloxone prior to PPV (60%; n=33/55) compared to patients without a known history (30%; n=9/30).

Conclusion: Overall these preliminary data suggest that during BLS naloxone administration, the majority of cases did not follow at least one component of the standard protocol for patients with respiratory depression. This study suggests that further education and more research are needed to better understand the decision-making processes of prehospital providers to ensure adherence to standard protocols.

Closed-loop wearable naloxone injector system

Overdoses from non-medical use of opioids can lead to hypoxemic/hypercarbic respiratory failure, cardiac arrest, and death when left untreated. Opioid toxicity is readily reversed with naloxone, a competitive antagonist that can restore respiration. However, there remains a critical need for technologies to administer naloxone in the event of unwitnessed overdose events. We report a closed-loop wearable injector system that measures respiration and apneic motion associated with an opioid overdose event using a pair of on-body accelerometers, and administers naloxone subcutaneously upon detection of an apnea. Our proof-of-concept system has been evaluated in two environments: (i) an approved supervised injection facility (SIF) where people self-inject opioids under medical supervision and (ii) a hospital environment where we simulate opioid-induced apneas in healthy participants. In the SIF (n = 25), our system identified breathing rate and post-injection respiratory depression accurately when compared to a respiratory belt. In the hospital, our algorithm identified simulated apneic events and successfully injected participants with 1.2 mg of naloxone. Naloxone delivery was verified by intravenous blood draw post-injection for all participants. A closed-loop naloxone injector system has the potential to complement existing evidence-based harm reduction strategies and, in the absence of bystanders, help make opioid toxicity events functionally witnessed and in turn more likely to be successfully resuscitated.

Drug and Chemical Poisoning Patterns in Makkah Region, Saudi Arabia

This research reveals that drugs and chemicals poisoning have been reported to have severe and fetal side effects on health provided by doctors in statistics and periodical records. This work aimed to explore the interaction among drug and chemical poisoning patterns concerning risk factors, especially gender, age, exposure circumstances, and outcomes in the Makkah region. A retrospective analysis was of clinical drug and chemical poisoning cases (2014-2015). The data were retrieved from the Department of Environmental and Occupational Health, Ministry of Health, Makkah, Saudi Arabia. The Saudi Arabia Ministry of Health received 1216 reports of drug and chemical poisoning during 2014-2015 in Makkah. This study has found that, the most affected gender was that of males (65%). The most affected age category with drug poisoning was over 15 years old (67%), but under 5 years for chemical poisoning (60%). The majority of drug poisoning cases are unknown drugs (42%), which accidental poisoning was a minority compared with other drug causes (27%). Chemical poisoning accidents were the majority causes of the recorded cases (63%). We reported healthy recovered without complications for most patients from drug and chemical poisoning (85-95%). Antidotes were administered in only (5%) of cases, and fatalities were reported (0.5% of cases). We have shown a flagrant increase in the number of people poisoned by drugs and chemical agents during 2015. Increases poisoning cases involved both genders and all studied age categories, especially males over 15 years up to 25 (drugs) and < 5 years (chemicals). Most cases were accidental (chemicals) and reported healthy recovery for most patients.

Biosurveillance of Drug Overdoses and Substance Misuse Treated in Selected Emergency Departments in Minnesota, 2017-2020

OBJECTIVES

Increasing knowledge about the toxicology of drug overdose and substance misuse (DOSM) is important in improving our understanding of the epidemic. We describe the Minnesota Drug Overdose and Substance Use Pilot Surveillance Activity, which started collecting data on emergency department (ED) visits attributable to DOSM in 2017, with a focus on the toxicology results of a subset of clinical encounters.

METHODS

From November 1, 2017, through January 30, 2020, we collected near-real-time data on DOSM-related ED encounters. The Minnesota Department of Health Public Health Laboratory tested leftover clinical specimens (blood and/or urine) for the presence of various substances for patients who died, were hospitalized, had an atypical clinical presentation, or were part of a local drug overdose cluster. Testing looked for >250 drugs or their metabolites, including those commonly misused (eg, methamphetamine, cocaine), prescription medications, synthetic cannabinoids and cathinones, and opioids. We describe characteristics of the overall group and a subgroup of clinical encounters with toxicology results.

RESULTS

Specimens submitted from 6 EDs during the study period represented 239 clinical encounters. Methamphetamine was the most frequently detected substance (67.4%) but was suspected in only 45.6% of encounters. At least 1 opioid was detected in 42.5% of encounters but suspected in only 29.7%. Testing also detected potential adulterants and additives (eg, fentanyl, fentanyl analogues, levamisole) and showed frequent patient exposure to substances not reported by patients or suspected by clinicians. Nearly half (44.4%) of clinical encounters had >1 substance detected.

CONCLUSIONS

ED surveillance for DOSM encounters, enhanced by toxicology testing, can provide local situational awareness on overdoses, prevent potential mischaracterization of the true drug overdose epidemic, and inform harm reduction and drug overdose prevention efforts.

Housing conditions and microbial environment do not affect the efficacy of vaccines for treatment of opioid use disorders in mice and rats

Vaccines offer a promising prophylactic and therapeutic intervention to counteract opioid use disorders (OUD) and fatal overdoses. Vaccines generate opioid-specific antibodies that bind the target opioid, reducing drug distribution to the brain and preventing drug-induced behavioral and pharmacological effects. Due to their selectivity, anti-opioid vaccines can be administered in combination with FDA-approved medications. Because patients with OUD or other substance use disorders may be affected by other multifactorial co-morbidities, such as infection or depression, it is important to test whether vaccine efficacy is modified by factors that may impact individual innate or adaptive immunity. To that end, this study tested whether housing conditions would affect the efficacy of two lead vaccine formulations targeting oxycodone and fentanyl in male mice and rats, and further analyzed whether differences in the gastrointestinal (GI) microbiome would be correlated with either vaccine efficacy or housing conditions. Results showed that housing mice and rats in either conventional (non-controlled) or specific pathogen-free (SPF, sterile barrier maintained) environment did not affect vaccine-induced antibody responses against oxycodone and fentanyl, nor their efficacy against oxycodone- and fentanyl-induced antinociception, respiratory depression, and bradycardia. Differences in the GI microbiome detected via 16S rRNA gene sequencing were related to the housing environment. This study supports use of anti-opioid vaccines in clinical populations that may display deficits in microbiome function.

Bridging the gap between in silico and in vivo by modeling opioid disposition in a kidney proximal tubule microphysiological system

Opioid overdose, dependence, and addiction are a major public health crisis. Patients with chronic kidney disease (CKD) are at high risk of opioid overdose, therefore novel methods that provide accurate prediction of renal clearance (CL_r) and systemic disposition of opioids in CKD patients can facilitate the optimization of therapeutic regimens. The present study aimed to predict renal clearance and systemic disposition of morphine and its active metabolite morphine-6-glucuronide (M6G) in CKD patients using a vascularized human proximal tubule microphysiological system (VPT-MPS) coupled with a parent-metabolite full body physiologically-based pharmacokinetic (PBPK) model. The VPT-MPS, populated with a human umbilical vein endothelial cell (HUVEC) channel and an adjacent human primary proximal tubular epithelial cells (PTEC) channel, successfully demonstrated secretory transport of morphine and M6G from the HUVEC channel into the PTEC channel. The in vitro data generated by VPT-MPS were incorporated into a mechanistic kidney model and parent-metabolite full body PBPK model to predict CL_r and systemic disposition of morphine and M6G, resulting in successful prediction of CL_r and the plasma concentration–time profiles in both healthy subjects and CKD patients. A microphysiological system together with mathematical modeling successfully predicted renal clearance and systemic disposition of opioids in CKD patients and healthy subjects.

Characterizing Opioid Overdoses Using Emergency Medical Services Data : A Case Definition Algorithm Enhanced by Machine Learning

OBJECTIVES

Tracking nonfatal overdoses in the escalating opioid overdose epidemic is important but challenging. The objective of this study was to create an innovative case definition of opioid overdose in North Carolina emergency medical services (EMS) data, with flexible methodology for application to other states' data.

METHODS

This study used de-identified North Carolina EMS encounter data from 2010-2015 for patients aged >12 years to develop a case definition of opioid overdose using an expert knowledge, rule-based algorithm reflecting whether key variables identified drug use/poisoning or overdose or whether the patient received naloxone. We text mined EMS narratives and applied a machine-learning classification tree model to the text to predict cases of opioid overdose. We trained models on the basis of whether the chief concern identified opioid overdose.

RESULTS

Using a random sample from the data, we found the positive predictive value of this case definition to be 90.0%, as compared with 82.7% using a previously published case definition. Using our case definition, the number of unresponsive opioid overdoses increased from 3412 in 2010 to 7194 in 2015. The corresponding monthly rate increased by a factor of 1.7 from January 2010 (3.0 per 1000 encounters; n = 261 encounters) to December 2015 (5.1 per 1000 encounters; n = 622 encounters). Among EMS responses for unresponsive opioid overdose, the prevalence of naloxone use was 83%.

CONCLUSIONS

This study demonstrates the potential for using machine learning in combination with a more traditional substantive knowledge algorithm-based approach to create a case definition for opioid overdose in EMS data.

Colorado's first year of extreme risk protection orders

Background

Extreme Risk Protection Orders (ERPOs) are a relatively new type of law that are being considered or implemented in many states in the United States. Colorado’s law went into effect on January 1, 2020, after significant controversy and concern over potential misuse of the law to confiscate weapons; many (n = 37 of 64) counties declared themselves “2nd Amendment (2A) sanctuaries” and said they would not enforce the law. Here, reviewed the patterns of use of the law during its first year.

Methods

We obtained all court records for ERPO petitions filed between January 1 and December 31, 2020. Data elements were abstracted by trained staff using a standardized guide. We calculated the proportion of petitions that were approved or denied/dismissed, identified cases of obvious misuse, and examined patterns by 2A county status.

Finding and results

In 2020, 109 ERPO petitions were filed in Colorado; of these, 61 were granted for a temporary ERPO and 49 for a full (year-long) ERPO. Most petitions filed by law enforcement officers were granted (85%), compared to only 15% of petitions filed by family or household members. Of the 37 2A sanctuary counties, 24% had at least one petition filed, versus 48% of non-2A sanctuary counties. Across the 2A counties, there were 1.52 ERPOs filed per 100,000 population, compared to 2.05 ERPOs filed per 100,000 in non-2A counties. There were 4 cases of obvious law misuse; none of those petitions resulted in an ERPO or firearm confiscation.

Conclusion

State-level studies suggest ERPOs may prevent firearm injuries. Robust implementation, however, is critical for maximal effect. Understanding ERPO experiences and challenges can inform policy creation and enaction in other states, including identifying how best to address concerns and facilitate evaluation.

Examining prevalence and correlates of smoking opioids in British Columbia: opioids are more often smoked than injected

BACKGROUND

British Columbia (BC) is in the midst of an opioid overdose crisis. Since 2017, smoking illicit drugs has been the leading mode of drug administration causing overdose death. Yet, little is known about people who smoke opioids, and factors underlying choice of mode of administration. The study objectives are to identify the prevalence and correlates associated with smoking opioids.

METHODS

The Harm Reduction Client Survey is a monitoring tool used by the BC Centre for Disease Control since 2012. This survey is disseminated to harm reduction sites across BC to understand drug use trends and drug-related harms. We examined data from the survey administered October-December 2019 and performed descriptive, univariate, and multivariate analyses to better understand factors associated with smoking opioids.

RESULTS

A total of 369 people who used opioids in the past 3 days were included, of whom 251 (68.0%) reported smoking opioids. A total of 109 (29.5%) respondents experienced an overdose in the past 6 months; of these 79 (72.5%) smoked opioids. Factors significantly associated with smoking opioids were: living in a small community (AOR =2.41, CI =1.27-4.58), being a woman (AOR = 1.84, CI = 1.03-3.30), age under 30 (AOR = 5.41, CI = 2.19-13.40) or 30-39 (AOR = 2.77, CI = 1.33-5.78) compared to age ≥ 50, using drugs alone (AOR = 2.98, CI = 1.30-6.83), and owning a take-home naloxone kit (AOR = 2.01, CI = 1.08-3.72). Reported use of methamphetamines within the past 3 days was strongly associated with smoking opioids (AOR = 6.48, CI = 3.51-11.96).

CONCLUSIONS

Our findings highlight important correlates associated with smoking opioids, particularly the recent use of methamphetamines. These findings identify actions to better respond to the overdose crisis, such as targeted harm reduction approaches, educating on safer smoking, advocating for consumption sites where people can smoke drugs, and providing a regulated supply of opioids that can be smoked.

Pharmacologic and Clinical Considerations of Nalmefene, a Long Duration Opioid Antagonist, in Opioid Overdose

Opioid use disorder is a well-established and growing problem in the United States. It is responsible for both psychosocial and physical damage to the affected individuals with a significant mortality rate. Given both the medical and non-medical consequences of this epidemic, it is important to understand the current treatments and approaches to opioid use disorder and acute opioid overdose. Naloxone is a competitive mu-opioid receptor antagonist that is used for the reversal of opioid intoxication. When given intravenously, naloxone has an onset of action of approximately 2 min with a duration of action of 60–90 min. Related to its empirical dosing and short duration of action, frequent monitoring of the patient is required so that the effects of opioid toxicity, namely respiratory depression, do not return to wreak havoc. Nalmefene is a pure opioid antagonist structurally similar to naltrexone that can serve as an alternative antidote for reversing respiratory depression associated with acute opioid overdose. Nalmefene is also known as 6-methylene naltrexone. Its main features of interest are its prolonged duration of action that surpasses most opioids and its ability to serve as an antidote for acute opioid overdose. This can be pivotal in reducing healthcare costs, increasing patient satisfaction, and redistributing the time that healthcare staff spend monitoring opioid overdose patients given naloxone.

Treatment of overdose in the synthetic opioid era

Overdose deaths are often viewed as the leading edge of the opioid epidemic which has gripped the United States over the past two decades (Skolnick, 2018a). This emphasis is perhaps unsurprising because opioid overdose is both the number-one cause of death for individuals between 25 and 64 years old (Dezfulian et al., 2021) and a significant contributor to the decline in average lifespan (Dowell et al., 2017). Exacerbated by the COVID 19 pandemic, it was estimated there were 93,400 drug overdose deaths in the United States during the 12 months ending December 2020, with more than 69,000 (that is, >74%) of these fatalities attributed to opioid overdose (Ahmad et al., 2021). However, the focus on mortality statistics (Ahmad et al., 2021; Shover et al., 2020) tends to obscure the broader medical impact of nonfatal opioid overdose. Analyses of multiple databases indicate that for each opioid-induced fatality, there are between 6.4 and 8.4 non-fatal overdoses, exacting a significant burden on both the individual and society. Over the past 7-8 years, there has been an alarming increase in the misuse of synthetic opioids ("synthetics"), primarily fentanyl and related piperidine-based analogs. Within the past 2-3 years, a structurally unrelated class of high potency synthetics, benzimidazoles exemplified by etonitazene and isotonitazene ("iso"), have also appeared in illicit drug markets (Thompson, 2020; Ujvary et al. 2021). In 2020, it was estimated that over 80% of fatal opioid overdoses in the United States now involve synthetics (Ahmad et al., 2021). The unique physicochemical and pharmacological properties of synthetics described in this review are responsible for both the morbidity and mortality associated with their misuse as well as their widespread availability. This dramatic increase in the misuse of synthetics is often referred to as the "3rd wave" (Pardo et al., 2019; Volkow and Blanco, 2020) of the opioid epidemic. Among the consequences resulting from misuse of these potent opioids is the need for higher doses of the competitive antagonist, naloxone, to reverse an overdose. The development of more effective reversal agents such as those described in this review is an essential component of a tripartite strategy (Volkow and Collins, 2017) to reduce the biopsychosocial impact of opioid misuse in the "synthetic era".

Individual and Community Factors Associated with Naloxone Co-prescribing Among Long-term Opioid Patients: a Retrospective Analysis

BACKGROUND

Naloxone co-prescribing to individuals at increased opioid overdose risk is a key component of opioid overdose prevention efforts.

OBJECTIVE

Examine naloxone co-prescribing in the general population and assess how co-prescribing varies by individual and community characteristics.

DESIGN

Retrospective cross-sectional study. We conducted a multivariable logistic regression of 2017-2018 de-identified pharmacy claims representing 90% of all prescriptions filled at retail pharmacies in 50 states and the District of Columbia.

PATIENTS

Individuals with opioid analgesic treatment episodes > 90 days MAIN MEASURES: Outcome was co-prescribed naloxone. Predictor variables included insurance type, primary prescriber specialty, receipt of concomitant benzodiazepines, high-dose opioid episode, county urbanicity, fatal overdose rates, poverty rates, and primary care health professional shortage areas.

KEY RESULTS

Naloxone co-prescribing occurred in 2.3% of long-term opioid therapy episodes. Medicaid (aOR 1.87, 95%CI 1.84 to 1.90) and Medicare (aOR 1.48, 95%CI 1.46 to 1.51) episodes had higher odds of naloxone co-prescribing than commercial insurance episodes, while cash pay (aOR 0.77, 95%CI 0.74 to 0.80) and other insurance episodes (aOR 0.81, 95%CI 0.79 to 0.83) had lower odds. Odds of naloxone co-prescribing were higher among high-dose opioid episodes (aOR 3.19, 95%CI 3.15 to 3.23), when concomitant benzodiazepines were prescribed (aOR 1.12, 95%CI 1.10 to 1.14), and in counties with higher fatal overdose rates.

CONCLUSION

Co-prescription of naloxone represents a tangible clinical action that can be taken to help prevent opioid overdose deaths. However, despite recommendations to co-prescribe naloxone to patients at increased risk for opioid overdose, we found that co-prescribing rates remain low overall. States, insurers, and health systems should consider implementing strategies to facilitate increased co-prescribing of naloxone to at-risk individuals.

[Overdose from a patch]

HISTORY AND CLINICAL FINDINGS

We present the case of an 89-year-old patient with impaired consciousness for whom the emergency services were called. She was soporose and showed a pronounced generalized muscle rigidity. Due to a third-party history the incorrect use of a fentanyl patch was found out to be at cause.

TREATMENT AND CLINICAL COURSE

The antidote administration of naloxone led to restoration. The need for repetitive administration confirmed the clinical hypothesis.

CONCLUSION

The application of fentanyl via the skin in the form of transdermal therapeutic systems (TTS) has become more popular over the years. Incorrect administration causes intoxication with the leading symptoms of loss of consciousness and respiratory depression. This case report extends the spectrum of symptoms to include skeletal muscle rigidity otherwise only described in connection with intravenous administration, especially in anaesthetic settings.

Design, synthesis, and preliminary evaluation of a potential synthetic opioid rescue agent

Background

One of the most prominent opioid analgesics in the United States is the high potency agonist fentanyl. It is used in the treatment of acute and chronic pain and as an anesthetic adjuvant. When used inappropriately, however, ingestion of just a few milligrams of fentanyl or other synthetic opioid can cause opioid-induced respiratory depression (OIRD), often leading to death. Currently, the treatment of choice for OIRD is the opioid receptor antagonist naloxone. Recent reports, however, suggest that higher doses or repeated dosing of naloxone (due to recurrence of respiratory depression) may be required to reverse fully fentanyl-induced respiratory depression, rendering this treatment inadequate. To combat this synthetic opioid overdose crisis, this research aims at identifying a novel opioid reversal agent with enhanced efficacy towards fentanyl and other synthetic opioids.

Methods

A series of naltrexone analogues were characterized for their ability to antagonize the effects of fentanyl in vitro utilizing a modified forskolin-induced cAMP accumulation assay. Lead analogue 29 was chosen to undergo further PK studies, followed by in vivo pharmacological analysis to determine its ability to antagonize opioid-induced antinociception in the hot plate assay.

Results

A series of potent MOR antagonists were identified, including the highly potent analogue 29 (IC₅₀ = 2.06 nM). Follow-up PK studies revealed 29 to possess near 100% bioavailability following IP administration. Brain concentrations of 29 surpassed plasma concentrations, with an apparent terminal half-life of ~ 80 min in mice. In the hot plate assay, 29 dose-dependently (0.01–0.1 mg/kg; IP) and fully antagonized the antinociception induced by oxycodone (5.6 mg/kg; IP). Furthermore, the dose of 29 that is fully effective in preventing oxycodone-induced antinociception (0.1 mg/kg) was ineffective against locomotor deficits caused by the KOR agonist U50,488.

Conclusions

Methods have been developed that have utility to identify enhanced rescue agents for the treatment of OIRD. Analogue 29, possessing potent MOR antagonist activity in vitro and in vivo, provides a promising lead in our search for an enhanced synthetic opioid rescue agent.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-021-00758-y.

Detection of opioid effect with pupillometry

BACKGROUND

Opioids produce pupillary constriction but their impact on pupillary unrest and the dynamic parameters of the pupillary light reflex have not been characterized. Given the increasing use of portable pupillometers for care of critically ill patients, it is important to distinguish between opioid effects on the pupil versus those that have been reported to arise from traumatic and ischemic brain insults. We undertook this study to determine which pupillary responses are most profoundly and consistently affected by a progressive infusion of remifentanil.

METHODS

We studied the effect of remifentanil on the pupil using two portable infrared pupillometers in 18 volunteers. One pupillometer measured pupillary unrest in ambient light (PUAL) and the other pupillometer measured neurological pupillary index (NPi), constriction velocity (CV), pupil diameter (PD), latency, and % reflex (% reflex) following a transient light flash. Remifentanil was administered at predetermined weight-adjusted rates to raise opioid effect site concentration up to a range known to produce respiratory depression and oxyhemoglobin desaturation, based on a previously published pharmacokinetic model.

RESULTS

PUAL was ablated by remifentanil, declining 94 ± 6% from baseline at the time of maximum drug effect. Other pupillary measurements decreased 50-65% from baseline. NPi was unchanged. At the time of oxyhemoglobin desaturation, deviations in PD, CV, and % reflex were widely scattered, whereas PUAL consistently approached zero.

CONCLUSION

PUAL is a highly specific indicator of central opioid effect. As a non-invasive measure, it may provide useful data to clinicians who prescribe opioids.

Opioid Modulation of the Gut-Brain Axis in Opioid-Associated Comorbidities

Growing evidence from animal and human studies show that opioids have a major impact on the composition and function of gut microbiota. This leads to disruption in gut permeability and altered microbial metabolites, driving both systemic and neuroinflammation, which in turn impacts central nervous system (CNS) homeostasis. Tolerance and dependence are the major comorbidities associated with prolonged opioid use. Inflammatory mediators and signaling pathways have been implicated in both opioid tolerance and dependence. We provide evidence that targeting the gut microbiome during opioid use through prebiotics, probiotics, antibiotics, and fecal microbial transplantation holds the greatest promise for novel treatments for opioid abuse. Basic research and clinical trials are required to examine what is more efficacious to yield new insights into the role of the gut-brain axis in opioid abuse.

Neurocognitive impairments and brain abnormalities resulting from opioid-related overdoses: A systematic review

BACKGROUND

Non-fatal opioid-related overdoses have increased significantly over the past two decades and there have been increasing reports of brain injuries and/or neurocognitive impairments following overdose events. Limited preclinical research suggests that opioid overdoses may cause brain injury; however, little is known about such injuries in humans. The purpose this systematic review is to summarize existing studies on neurocognitive impairments and/or brain abnormalities associated with an opioid-related overdose in humans.

METHODS

PubMed, Web of Science, Ovid MEDLINE and PsyINFO were searched, without year restrictions, and identified 3099 articles. An additional 24 articles were identified by reviewing references. Articles were included if they were published in English, reported study findings in humans, included individuals 18 years of age or older, and reported an objective measure of neurocognitive impairments and/or brain abnormalities resulting from an opioid-related overdose. Six domains of bias (selection, performance, attrition, detection (two dimensions) and reporting were evaluated and themes were summarized.

RESULTS

Seventy-nine journal articles, published between 1973-2020, were included in the review. More than half of the articles were case reports (n = 44) and there were 11 cohort studies, 18 case series, and 6 case-control studies. All of the studies were categorized as at-risk of bias, few controlled for confounding factors, and methodological differences made direct comparisons difficult. Less than half of the studies reported toxicology results confirming an opioid-related overdose; 64.6 % reported brain MRI results and 27.8 % reported results of neuropsychological testing. Only two studies had within subject comparative data to document changes in the brain possibly associated with an overdose. Despite these limitations, existing publications suggest that brain injuries and neurocognitive impairments are associated with opioid overdose. Additional research is needed to establish the incidence of overdose-related brain injuries and the potential impact on functioning, as well as engagement in treatment of substance use disorders.

CONCLUSIONS

Respiratory depression is a defining characteristic of opioid overdose and prolonged cerebral hypoxia may cause brain injuries and/or neurocognitive impairments. The onset, characteristics, and duration of such injuries is variable and additional research is needed to understand their clinical implications.

A drug-related Good Samaritan Law and calling emergency medical services for drug overdoses in a Canadian setting

Background

People who use drugs (PWUD) are known to fear calling emergency medical services (EMS) for drug overdoses. In response, drug-related Good Samaritan Laws (GSLs) have been widely adopted in the USA and Canada to encourage bystanders to call emergency medical services (EMS) in the event of a drug overdose. However, the effect of GSLs on EMS-calling behaviours has been understudied. We sought to identify factors associated with EMS-calling, including the enactment of the Canadian GSL in May 2017, among PWUD in Vancouver, Canada, a setting with an ongoing overdose crisis.

Methods

Data were derived from three prospective cohort studies of PWUD in Vancouver in 2014–2018. Multivariable logistic regression was used to determine factors associated with EMS-calling among PWUD who witnessed an overdose event. An interrupted time series (ITS) analysis was employed to assess the impact of GSL on monthly prevalence of EMS-calling.

Results

Among 540 eligible participants, 321 (59%) were males and 284 (53%) reported calling EMS. In multivariable analysis, ever having administered naloxone three or more times (adjusted odds ratio [AOR] 2.00; 95% confidence interval [CI] 1.08–3.74) and residence in the Downtown Eastside (DTES) neighbourhood of Vancouver (AOR 1.96; 95% CI 1.23–3.13) were positively associated with EMS-calling, while living in a single occupancy hotel (SRO) was negatively associated with EMS-calling (AOR 0.51; 95% CI 0.30–0.86). The post-GSL enactment period was not associated with EMS-calling (AOR 0.81; 95% CI 0.52–1.25). The ITS found no significant difference in the monthly prevalence of EMS-calling between pre- and post-GSL enactment periods.

Conclusion

We observed EMS being called about half the time and the GSL did not appear to encourage EMS-calling. We also found that individuals living in SROs were less likely to call EMS, which raises concern given that fatal overdose cases are concentrated in SROs in our setting. The link between many naloxone administrations and EMS-calling could indicate that those with prior experience in responding to overdose events were more willing to call EMS. Increased efforts are warranted to ensure effective emergency responses for drug overdoses among PWUD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12954-021-00537-w.

Use of Naloxone in 9-1-1 Patients without Respiratory Depression in Los Angeles County, California (USA)

INTRODUCTION

Along with an increase in opioid deaths, there has been a desire to increase the accessibility of naloxone. However, in the absence of respiratory depression, naloxone is unlikely to be beneficial and may be deleterious if it precipitates withdrawal in individuals with central nervous system (CNS) depression due to non-opioid etiologies.

OBJECTIVE

The aim of this study was to evaluate how effective prehospital providers were in administering naloxone.

METHODS

This is a retrospective study of naloxone administration in two large urban Emergency Medical Service (EMS) systems. The proportion of patients who had a respiratory rate of at least 12 breaths per minute at the time of naloxone administration by prehospital providers was determined.

RESULTS

During the two-year study period, 2,580 patients who received naloxone by prehospital providers were identified. The median (interquartile range) respiratory rate prior to naloxone administration was 12 (6-16) breaths per minute. Using an a priori respiratory rate of under 12 breaths per minute to define respiratory depression, only 1,232 (47.8%; 95% CI, 50.3%-54.2%) subjects who received naloxone by prehospital providers had respiratory depression.

CONCLUSION

This study showed that EMS providers in Los Angeles County, California (USA) frequently administered naloxone to individuals without respiratory depression.

Naloxone dosing in the era of ultra-potent opioid overdoses: a systematic review

OBJECTIVES

Evaluate the relationship between naloxone dose (initial and cumulative) and opioid toxicity reversal and adverse events in undifferentiated and presumed fentanyl/ultra-potent opioid overdoses.

METHODS

We searched Embase, MEDLINE, Cochrane Central Register of Controlled Trials, DARE, CINAHL, Science Citation Index, reference lists, toxicology websites, and conference proceedings (1972 to 2018). We included interventional, observational, and case studies/series reporting on naloxone dose and opioid toxicity reversal or adverse events in people >12 years old.

RESULTS

A total of 174 studies (110 case reports/series, 57 observational, 7 interventional) with 26,660 subjects (median age 35 years; 74% male). Heterogeneity precluded meta-analysis. Where reported, we abstracted naloxone dose and proportion of patients with toxicity reversal. Among patients with presumed exposure to fentanyl/ultra-potent opioids, 56.9% (617/1,085) responded to an initial naloxone dose ≤0.4 mg compared with 80.2% (170/212) of heroin users, and 30.4% (7/23) responded to an initial naloxone dose >0.4 mg compared with 59.1% (1,434/2,428) of heroin users. Among patients who responded, median cumulative naloxone doses were higher for presumed fentanyl/ultra-potent opioids than heroin overdoses in North America, both before 2015 (fentanyl/ultra-potent opioids: 1.8 mg [interquartile interval {IQI}, 1.0, 4.0]; heroin: 0.8 mg [IQI, 0.4, 0.8]) and after 2015 (fentanyl/ultra-potent opioids: 3.4 mg [IQI, 3.0, 4.1]); heroin: 2 mg [IQI, 1.4, 2.0]). Where adverse events were reported, 11% (490/4,414) of subjects experienced withdrawal. Variable reporting, heterogeneity and poor-quality studies limit conclusions.

CONCLUSIONS

Practitioners have used higher initial doses, and in some cases higher cumulative naloxone doses to reverse toxicity due to presumed fentanyl/ultra-potent opioid exposure compared with other opioids. High-quality comparative naloxone dosing studies assessing effectiveness and safety are needed.

Impact of the Opioid Epidemic

In recent years the prescription opioid overdose epidemic has decreased, but has been more than offset by increases in overdose caused by fentanyl and fentanyl analogues. Opioid overdose patients should receive naloxone if they have significant respiratory depression and/or loss of protective airway reflexes. Patients who receive naloxone should be observed for recurrent opioid effects. Patients with opioid overdose may be admitted to the intensive care unit for naloxone infusions, treatment of noncardiogenic pulmonary edema, autonomic instability, or sequelae of hypoxia-ischemia or cardiac arrest. Primary and secondary prevention are important to reduce the number of people with life-threatening opioid overdose.

Treating patients with opioid overdose at a primary care emergency outpatient clinic: a cost-minimization analysis

BACKGROUND

Treating patients with acute poisoning by substances of abuse in a primary care emergency clinic has previously been shown to be a safe strategy. We conducted an economic evaluation of this strategy compared to hospital treatment, which is the usual strategy.

METHODS

Assuming equal health outcomes, we conducted a cost-minimization analysis. We constructed a representative opioid overdose patient based on a cohort of 359 patients treated for opioid overdose at the Oslo Accident and Emergency Outpatient Clinic (OAEOC) from 1.10.2011 to 30.9.2012. Using a health care system perspective, we estimated the expected resources used on the representative patient in primary care based on data from the observed OAEOC cohort and on information from key informants at the OAEOC. A likely course of treatment of the same patient in a hospital setting was established from information from key informants on provider procedures at Drammen Hospital, as were estimates of hospital use of resources. We calculated expected costs for both settings. Given that the treatments usually last for less than one day, we used undiscounted cost values.

RESULTS

The estimated per patient cost in primary care was 121 EUR (2018 EUR 1.00 = NOK 9.5962), comprising 97 EUR on personnel costs and 24 EUR on treatment costs. In the hospital setting, the corresponding cost was 612 EUR, comprising 186 EUR on personnel costs, 183 EUR on treatment costs, and 243 EUR associated with intensive care unit admission. The point estimate of the cost difference per patient was 491 EUR, with a low-difference scenario estimated at 264 EUR and a high-difference scenario at 771 EUR.

CONCLUSIONS

Compared to hospital treatment, treating patients with opioid overdose in a primary care setting costs substantially less. Our findings are probably generalizable to poisoning with other substances of abuse. Implementing elements of the OAEOC procedure in primary care emergency clinics and in hospital emergency departments could improve the use of health care resources.

Global transcriptome analysis of rat dorsal root ganglia to identify molecular pathways involved in incisional pain

To develop non-opioid therapies for postoperative incisional pain, we must understand its underlying molecular mechanisms. In this study, we assessed global gene expression changes in dorsal root ganglia neurons in a model of incisional pain to identify pertinent molecular pathways. Male, Sprague-Dawley rats underwent infiltration of 1% capsaicin or vehicle into the plantar hind paw (n = 6-9/group) 30 min before plantar incision. Twenty-four hours after incision or sham (control) surgery, lumbar L4-L6 dorsal root ganglias were collected from rats pretreated with vehicle or capsaicin. RNA was isolated and sequenced by next generation sequencing. The genes were then annotated to functional networks using a knowledge-based database, Ingenuity Pathway Analysis. In rats pretreated with vehicle, plantar incision caused robust hyperalgesia, up-regulated 36 genes and downregulated 90 genes in dorsal root ganglias one day after plantar incision. Capsaicin pretreatment attenuated pain behaviors, caused localized denervation of the dermis and epidermis, and prevented the incision-induced changes in 99 of 126 genes. The pathway analyses showed altered gene networks related to increased pro-inflammatory and decreased anti-inflammatory responses in dorsal root ganglias. Insulin-like growth factor signaling was identified as one of the major gene networks involved in the development of incisional pain. Expression of insulin-like growth factor -2 and IGFBP6 in dorsal root ganglia were independently validated with quantitative real-time polymerase chain reaction. We discovered a distinct subset of dorsal root ganglia genes and three key signaling pathways that are altered 24 h after plantar incision but are unchanged when incision was made after capsaicin infiltration in the skin. Further exploration of molecular mechanisms of incisional pain may yield novel therapeutic targets.

Wooden Chest syndrome: The atypical pharmacology of fentanyl overdose

WHAT IS KNOWN AND OBJECTIVE

A large percentage of opioid overdose fatalities involve fentanyl or one of its legal or illegal analogs (F/FAs). Is there something about the pharmacology of these drugs that make them unusually dangerous in an overdose?

COMMENT

Some of the reasons for the dangers of overdose of F/FAs is their high potency and low cost (that leads to wide distribution). But it is rarely asked if the basic pharmacology of F/FAs differ in some fundamental way from conventional opioids such as morphine and heroin. In addition to centrally mediated respiratory depression via opioid receptors, F/FAs cause rigidity in the key respiratory muscles of the chest, upper airway and diaphragm ("wooden chest syndrome," WCS) by a non-opioid mechanism.

WHAT IS NEW AND CONCLUSION

WCS is an atypical pharmacology of F/FAs. Because of its rapid onset and non-opioid mechanism, WCS makes F/FA overdose particularly dangerous.

Mortality and concurrent use of opioids and hypnotics in older patients: A retrospective cohort study

BACKGROUND

Benzodiazepine hypnotics and the related nonbenzodiazepine hypnotics (z-drugs) are among the most frequently prescribed medications for older adults. Both can depress respiration, which could have fatal cardiorespiratory effects, particularly among patients with concurrent opioid use. Trazodone, frequently prescribed in low doses for insomnia, has minimal respiratory effects, and, consequently, may be a safer hypnotic for older patients. Thus, for patients beginning treatment with benzodiazepine hypnotics or z-drugs, we compared deaths during periods of current hypnotic use, without or with concurrent opioids, to those for comparable patients receiving trazodone in doses up to 100 mg.

METHODS AND FINDINGS

The retrospective cohort study in the United States included 400,924 Medicare beneficiaries 65 years of age or older without severe illness or evidence of substance use disorder initiating study hypnotic therapy from January 2014 through September 2015. Study endpoints were out-of-hospital (primary) and total mortality. Hazard ratios (HRs) were adjusted for demographic characteristics, psychiatric and neurologic disorders, cardiovascular and renal conditions, respiratory diseases, pain-related diagnoses and medications, measures of frailty, and medical care utilization in a time-dependent propensity score-stratified analysis. Patients without concurrent opioids had 32,388 person-years of current use, 260 (8.0/1,000 person-years) out-of-hospital and 418 (12.9/1,000) total deaths for benzodiazepines; 26,497 person-years,150 (5.7/1,000) out-of-hospital and 227 (8.6/1,000) total deaths for z-drugs; and 16,177 person-years,156 (9.6/1,000) out-of-hospital and 256 (15.8/1,000) total deaths for trazodone. Out-of-hospital and total mortality for benzodiazepines (respective HRs: 0.99 [95% confidence interval, 0.81 to 1.22, p = 0.954] and 0.95 [0.82 to 1.14, p = 0.513] and z-drugs (HRs: 0.96 [0.76 to 1.23], p = 0.767 and 0.87 [0.72 to 1.05], p = 0.153) did not differ significantly from that for trazodone. Patients with concurrent opioids had 4,278 person-years of current use, 90 (21.0/1,000) out-of-hospital and 127 (29.7/1,000) total deaths for benzodiazepines; 3,541 person-years, 40 (11.3/1,000) out-of-hospital and 64 (18.1/1,000) total deaths for z-drugs; and 2,347 person-years, 19 (8.1/1,000) out-of-hospital and 36 (15.3/1,000) total deaths for trazodone. Out-of-hospital and total mortality for benzodiazepines (HRs: 3.02 [1.83 to 4.97], p < 0.001 and 2.21 [1.52 to 3.20], p < 0.001) and z-drugs (HRs: 1.98 [1.14 to 3.44], p = 0.015 and 1.65 [1.09 to 2.49], p = 0.018) were significantly increased relative to trazodone; findings were similar with exclusion of overdose deaths or restriction to those with cardiovascular causes. Limitations included composition of the study cohort and potential confounding by unmeasured variables.

CONCLUSIONS

In US Medicare beneficiaries 65 years of age or older without concurrent opioids who initiated treatment with benzodiazepine hypnotics, z-drugs, or low-dose trazodone, study hypnotics were not associated with mortality. With concurrent opioids, benzodiazepines and z-drugs were associated with increased out-of-hospital and total mortality. These findings indicate that the dangers of benzodiazepine-opioid coadministration go beyond the documented association with overdose death and suggest that in combination with opioids, the z-drugs may be more hazardous than previously thought.

Pronounced Regional Disparities in United States Methadone Distribution

BACKGROUND

Methadone is an evidence-based treatment for opioid use disorder (OUD) and pain management. Methadone for OUD may be difficult for some patients to access, particularly those in rural areas.

OBJECTIVE

The purpose of this study was to characterize methadone distribution patterns between 2017 and 2019 across the United States.

METHODS

The US Drug Enforcement Administration's Automated Reports and Consolidated Ordering System was used to acquire the number of opioid treatment programs (OTPs) per state and methadone distribution weight in grams. Methadone distributions by weight, corrected for state population and number of OTPs, were compared from 2017 to 2019 between states, within regions, and nationally.

RESULTS

The national distribution of methadone increased +12.3% for OTPs but decreased -34.6% for pain. Whereas all states saw a decrease in pain distribution, the Northeast showed a significantly smaller decrease than all other regions. Additionally, the majority of states experienced an increase in distribution for OTPs, and most states demonstrated a relatively stable or increasing number of OTPs, with an +11.5% increase nationally. The number of OTPs per 100K state population ranged from 2.1 in Rhode Island to 0.0 in Wyoming.

CONCLUSION AND RELEVANCE

Although methadone distribution for OUD was increasing in the United States, the pronounced regional disparities identified warrant further consideration to improve patient access to this evidence-based pharmacotherapy, particularly in the Midwest and West regions. Greater implementation of telehealth and involvement of primary care into opioid treatment practice offer possible solutions to eliminating geographical treatment barriers.

A Nanoantidote Alleviates Glioblastoma Chemotoxicity without Efficacy Compromise

Cancer patients suffer from the toxicity of chemotherapy. Antidote, given as a remedy limiting poison, is an effective way to counteract toxicity. However, few antidotes abrogate chemotoxicity without compromising the therapeutic efficacy. Herein, a rationally designed nanoantidote can neutralize chemo-agents in normal cells but not enter tumors and thus would not interfere with the efficacy of tumor treatment. The nanoantidote, consisting of a dendrimer core wrapped by reductive cysteine, captures Temozolomide (TMZ, the glioblastoma standard chemotherapy). Meanwhile, thanks to the blood-brain barrier (BBB) and the size of the nanoantidote, the nanoantidote cannot enter glioblastoma. In murine models, the nanoantidote distributes in normal tissues without crossing the BBB, so it markedly reduces the chemotoxicity of TMZ and retains the original TMZ therapeutic efficacy. With most nanotechnologies focusing on antitumor treatment, this detoxicating strategy demonstrates a nanoplatform to reduce chemotoxicity using physiology barriers and introduces a new approach to nanomedicine for cancer chemotherapy.

Overdoses due to fentanyl and its analogues (F/FAs) push naloxone to the limit

WHAT IS KNOWN AND OBJECTIVE

Food and Drug Administration (FDA) risk evaluation and mitigation strategies (REMs) encourage emergency responders, paramedics, law enforcement agents, and even laypeople to be trained in the administration of naloxone with the intent of rescuing individuals from a known or suspected opioid overdose.

COMMENT

Although naloxone is generally safe and effective at reversing respiratory depression caused by a conventional opioid such as morphine or heroin by competing with the opioid and displacing it from the μ-opioid receptor, questions increasingly are arising as to whether naloxone can adequately reverse opioid overdoses that may involve the potent opioids fentanyl and its analogues (F/FAs). In other words, as more and more opioid overdoses involve F/FAs, can naloxone keep up?

WHAT IS NEW AND CONCLUSION

As a competitive antagonist at μ-opioid receptors, naloxone is often a life-saving agent in cases of overdose caused by conventional opioids, but it may not be versatile or powerful enough to combat the rising tide of overdoses due to fentanyl and its illicit analogues, or in cases of overdose involving combinations of opioids and non-opioids.

Neural basis of opioid-induced respiratory depression and its rescue

Opioid-induced respiratory depression (OIRD) causes death following an opioid overdose, yet the neurobiological mechanisms of this process are not well understood. Here, we show that neurons within the lateral parabrachial nucleus that express the µ-opioid receptor (PBL Oprm1 neurons) are involved in OIRD pathogenesis. PBL Oprm1 neuronal activity is tightly correlated with respiratory rate, and this correlation is abolished following morphine injection. Chemogenetic inactivation of PBL Oprm1 neurons mimics OIRD in mice, whereas their chemogenetic activation following morphine injection rescues respiratory rhythms to baseline levels. We identified several excitatory G protein-coupled receptors expressed by PBL Oprm1 neurons and show that agonists for these receptors restore breathing rates in mice experiencing OIRD. Thus, PBL Oprm1 neurons are critical for OIRD pathogenesis, providing a promising therapeutic target for treating OIRD in patients.