Pharmacokinetic Properties and Human Use Characteristics of an FDA-Approved Intranasal Naloxone Product for the Treatment of Opioid Overdose

Synthetic opioids have disrupted conventional wisdom for treating opioid overdose

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

Effects of Intranasal Naloxone on Hypoglycemia-Associated Autonomic Failure (HAAF) in Susceptible Individuals

CONTEXT

Hypoglycemia-associated autonomic failure (HAAF), defined as blunting of counter-regulatory hormone and symptom responses to recurrent hypoglycemia, remains a therapeutic challenge in diabetes treatment. The opioid system may play a role in HAAF pathogenesis since activation of opioid receptors induces HAAF. Blockade of opioid receptors with intravenous naloxone ameliorates HAAF experimentally, yet is not feasible therapeutically.

OBJECTIVE

To investigate the effects of opioid receptor blockade with intranasal naloxone on experimentally-induced HAAF.

DESIGN

Randomized, double-blinded, placebo-controlled crossover study.

SETTING

Academic research center.

PARTICIPANTS

Healthy non-diabetic volunteers.

INTERVENTIONS

Paired two-day studies, 5-10 weeks apart, each consisting of three consecutive hypoglycemic episodes (hyperinsulinemic hypoglycemic clamps, glucose nadir: 54 mg/dL): two on day 1 with administration of intranasal naloxone vs. placebo, followed by the third episode on day 2.

MAIN OUTCOME MEASURES

Differences in counter-regulatory hormones responses and hypoglycemia symptoms between first and third hypoglycemic episodes in naloxone vs. placebo studies.

RESULTS

Out of 17 participants, 9 developed HAAF, confirming variable inter-individual susceptibility. Among participants susceptible to HAAF, naloxone maintained some hormonal and symptomatic responses to hypoglycemia and prevented the associated requirement for increased glucose infusion. Unexpectedly, naloxone reduced plasma epinephrine and growth hormone responses to the first hypoglycemic episode but prevented further reduction with subsequent hypoglycemia.

CONCLUSIONS

This is the first study to report that intranasal naloxone, a widely used opioid receptor antagonist, may ameliorate some features of HAAF. Further investigation is warranted into mechanisms of variable inter-individual susceptibility to HAAF and the effects of intranasal naloxone in people with diabetes at risk for HAAF.

Reversal of Opioid-Induced Respiratory Depression in Healthy Volunteers: Comparison of Intranasal Nalmefene and Intranasal Naloxone

An open-label, randomized, crossover study in healthy volunteers compared the reversal of remifentanil-induced respiratory depression by intranasal (IN) naloxone hydrochloride (4 mg) to IN nalmefene (2.7 mg) (NCT04828005). Subjects were administered a hypercapnic gas mixture which produces an elevation in minute ventilation (MV), a result of the ventilatory response to hypercapnia. Subjects breathed a hypercapnic gas mixture through a tight-fitting mask for an initial period of 46 min prior to a series of mask "holidays" introduced to reduce subject discomfort and encourage study completion. Ten minutes after initiating the hypercapnic gas mixture, a remifentanil bolus was administered, and an infusion continued for the study duration. Subjects were administered either naloxone or nalmefene 15 min after initiating the remifentanil infusion and MV monitored for 21 min followed by a mask holiday. Both nalmefene and naloxone produced a time-dependent reversal of remifentanil-induced reductions in MV measured 2.5-20 min post administration. At the primary endpoint (5 min post administration), nalmefene increases in MV (5.75 L/min) were nearly twice that produced by naloxone (3.01 L/min) (P < .0009); the point estimate favors nalmefene, demonstrating non-inferiority and superiority. In this model of opioid-induced respiratory depression, nalmefene has a more rapid onset of action than naloxone, which required 20 min to achieve a comparable reversal of respiratory depression. Both nalmefene and naloxone were well tolerated by healthy volunteers. This rapid onset of action may prove particularly valuable in an era when over 90% of fatalities are linked to synthetic opioid overdose.

Comparison of intranasal naloxone and intranasal nalmefene in a translational model assessing the impact of synthetic opioid overdose on respiratory depression and cardiac arrest

Introduction

Using a validated translational model that quantitatively predicts opioid-induced respiratory depression and cardiac arrest, we compared cardiac arrest events caused by synthetic opioids (fentanyl, carfentanil) following rescue by intranasal (IN) administration of the μ-opioid receptor antagonists naloxone and nalmefene.

Methods

This translational model was originally developed by Mann et al. (Clin Pharmacol Ther 2022) to evaluate the effectiveness of intramuscular (IM) naloxone. We initially implemented this model using published codes, reproducing the effects reported by Mann et al. on the incidence of cardiac arrest events following intravenous doses of fentanyl and carfentanil as well as the reduction in cardiac arrest events following a standard 2 mg IM dose of naloxone. We then expanded the model in terms of pharmacokinetic and µ-opioid receptor binding parameters to simulate effects of 4 mg naloxone hydrochloride IN and 3 mg nalmefene hydrochloride IN, both FDA-approved for the treatment of opioid overdose. Model simulations were conducted to quantify the percentage of cardiac arrest in 2000 virtual patients in both the presence and absence of IN antagonist treatment.

Results

Following simulated overdoses with both fentanyl and carfentanil in chronic opioid users, IN nalmefene produced a substantially greater reduction in the incidence of cardiac arrest compared to IN naloxone. For example, following a dose of fentanyl (1.63 mg) producing cardiac arrest in 52.1% (95% confidence interval, 47.3-56.8) of simulated patients, IN nalmefene reduced this rate to 2.2% (1.0-3.8) compared to 19.2% (15.5-23.3) for IN naloxone. Nalmefene also produced large and clinically meaningful reductions in the incidence of cardiac arrests in opioid naïve subjects. Across dosing scenarios, simultaneous administration of four doses of IN naloxone were needed to reduce the percentage of cardiac arrest events to levels that approached those produced by a single dose of IN nalmefene.

Conclusion

Simulations using this validated translational model of opioid overdose demonstrate that a single dose of IN nalmefene produces clinically meaningful reductions in the incidence of cardiac arrest compared to IN naloxone following a synthetic opioid overdose. These findings are especially impactful in an era when >90% of all opioid overdose deaths are linked to synthetic opioids such as fentanyl.

Clinical Pharmacokinetics and Pharmacodynamics of Naloxone

Naloxone is a World Health Organization (WHO)-listed essential medicine and is the first choice for treating the respiratory depression of opioids, also by lay-people witnessing an opioid overdose. Naloxone acts by competitive displacement of opioid agonists at the μ-opioid receptor (MOR). Its effect depends on pharmacological characteristics of the opioid agonist, such as dissociation rate from the MOR receptor and constitution of the victim. Aim of treatment is a balancing act between restoration of respiration (not consciousness) and avoidance of withdrawal, achieved by titration to response after initial doses of 0.4-2 mg. Naloxone is rapidly eliminated [half-life (t1/2) 60-120 min] due to high clearance. Metabolites are inactive. Major routes for administration are intravenous, intramuscular, and intranasal, the latter primarily for take-home naloxone. Nasal bioavailability is about 50%. Nasal uptake [mean time to maximum concentration (Tmax) 15-30 min] is likely slower than intramuscular, as reversal of respiration lag behind intramuscular naloxone in overdose victims. The intraindividual, interindividual and between-study variability in pharmacokinetics in volunteers are large. Variability in the target population is unknown. The duration of action of 1 mg intravenous (IV) is 2 h, possibly longer by intramuscular and intranasal administration. Initial parenteral doses of 0.4-0.8 mg are usually sufficient to restore breathing after heroin overdose. Fentanyl overdoses likely require higher doses of naloxone. Controlled clinical trials are feasible in opioid overdose but are absent in cohorts with synthetic opioids. Modeling studies provide valuable insight in pharmacotherapy but cannot replace clinical trials. Laypeople should always have access to at least two dose kits for their interim intervention.

Fact vs. fiction: naloxone in the treatment of opioid-induced respiratory depression in the current era of synthetic opioids

Opioid-induced respiratory depression (OIRD) deaths are ~80,000 a year in the US and are a major public health issue. Approximately 90% of fatal opioid-related deaths are due to synthetic opioids such as fentanyl, most of which is illicitly manufactured and distributed either on its own or as an adulterant to other drugs of abuse such as cocaine or methamphetamine. Other potent opioids such as nitazenes are also increasingly present in the illicit drug supply, and xylazine, a veterinary tranquilizer, is a prevalent additive to opioids and other drugs of abuse. Naloxone is the main treatment used to reverse OIRD and is available as nasal sprays, prefilled naloxone injection devices, and generic naloxone for injection. An overdose needs to be treated as soon as possible to avoid death, and synthetic opioids such as fentanyl are up to 50 times more potent than heroin, so the availability of new, higher-dose, 5-mg prefilled injection or 8-mg intranasal spray naloxone preparations are important additions for emergency treatment of OIRDs, especially by lay people in the community. Higher naloxone doses are expected to reverse a synthetic overdose more rapidly and the current formulations are ideal for use by untrained lay people in the community. There are potential concerns about severe withdrawal symptoms, or pulmonary edema from treatment with high-dose naloxone. However, from the perspective of first responders, the balance of risks would point to administration of naloxone at the dose required to combat the overdose where the risk of death is very high. The presence of xylazines as an adulterant complicates the treatment of OIRDs, as naloxone is probably ineffective, although it will reverse the respiratory depression due to the opioid. For these patients, hospitalization is particularly vital. Education about the benefits of naloxone remains important not only in informing people about how to treat emergency OIRDs but also how to obtain naloxone. A call to emergency services is also essential after administering naloxone because, although the patient may revive, they may overdose again later because of the short half-life of naloxone and the long-lasting potency of fentanyl and its analogs.

Pharmacokinetic Properties of an FDA-approved Intranasal Nalmefene Formulation for the Treatment of Opioid Overdose

Nalmefene is a high-affinity, long-duration opioid antagonist that was approved in 1995 as an injection for the treatment of opiate overdose, but subsequently withdrawn (2008) for reasons other than safety or effectiveness. The dramatic rise in opioid overdose deaths over the past 7-8 years catalyzed the development of an intranasal (IN) formulation of nalmefene for the emergency treatment of opioid overdose. The studies described here compare the pharmacokinetic properties and safety profiles of an IN formulation containing nalmefene (2.7 mg in 0.1 mL) to an approved 1 mg intramuscular (IM) dose. IN nalmefene produced maximum plasma concentrations that were significantly higher than observed following the IM dose (12.2 and 1.77 ng/mL, respectively). The time to reach maximum plasma concentrations was also faster following IN administration (0.25 and 0.33 hours, respectively) with significant differences in plasma concentrations manifested as early as 2.5 minutes after administration (NCT04759768). The plasma half-life of nalmefene was similar following IM and IN administration (10.6-11.4 hours). Furthermore, dose-normalized nalmefene exposure was similar for both 1 spray in each nostril and 2 sprays in the same nostril compared to a single spray in each nostril (NCT05219669). There were no sex differences in the pharmacokinetic properties of either IN or IM nalmefene. In an era when almost 90% of opioid overdose deaths have been linked to high-potency synthetic opioids, the ability to rapidly deliver high concentrations of nalmefene could represent an important tool for reducing both morbidity and mortality.

A study protocol for a European, mixed methods, prospective, cohort study of the effectiveness of naloxone administration by community members, in reversing opioid overdose: NalPORS

BACKGROUND

Worldwide, opioid use causes more than 100,000 overdose deaths annually. Naloxone has proven efficacy in reversing opioid overdoses and is approved as an emergency antidote to opioid overdose. Take home naloxone (THN) programmes have been introduced to provide 'community members', who are likely to observe opioid overdoses, with naloxone kits and train them to recognise an overdose and administer naloxone. The acceptability and feasibility of THN programmes has been demonstrated, but the real-life effectiveness of naloxone administration by community members is not known. In recent years, the approval of several concentrated naloxone nasal-spray formulations (in addition to injectable formulations, eg.prenoxad) potentially increases acceptability and scope for wider provision. This study aims to determine the effectiveness of THN (all formulations) in real-world conditions.

METHODS

A European, multi-country, prospective cohort study, to assess the use of THN by community members to reverse opioid overdoses in a six-month, follow-up period. Participants provided with THN from participating harm reduction and drug treatment sites will be recruited to the study and followed-up for six months. We are particularly interested in the experiences of community members who have been provided with THN and have witnessed an opioid overdose. All participants who witness an opioid overdose during the six-month period (target approx. 600) will be asked to take part in a structured interview about this event. Of these, 60 will be invited to participate in a qualitative interview. A Post Authorisation Efficacy Study (PAES) for the concentrated nasal naloxone, Nyxoid, has been integrated into the study design.

DISCUSSION

There are many challenges involved in evaluating the real-life effectiveness of THN. It is not possible to use a randomised trial design, recruitment of community members provided with THN will depend upon recruitment sites distributing THN kits, and the type of THN received by participants will depend on regulations and on local clinical and policy decision-makers. Following up this population, some of whom may be itinerant, over the 6-month study period will be challenging, but we plan to maintain contact with participants through regular text message reminders and staff contact.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05072249. Date of Registration: 8.10.2021.

Re-examining Naloxone Pharmacokinetics After Intranasal and Intramuscular Administration Using the Finite Absorption Time Concept

BACKGROUND AND OBJECTIVES

Naloxone for opioid overdose treatment can be administered by intravenous injection, intramuscular injection, or intranasal administration. Published data indicate differences in naloxone pharmacokinetics depending on the route of administration. The aim of this study was to analyze pharmacokinetic data in the same way that we recently successfully applied the concept of the finite absorption time in orally administered drug formulations.

METHODS

Using the model equations already derived, we performed least squares analysis on 24 sets of naloxone concentration in the blood as a function of time.

RESULTS

We found that intramuscular and intranasal administration can be described more accurately when considering zero-order absorption kinetics for finite time compared with classical first order absorption kinetics for infinite time.

CONCLUSIONS

One-compartment models work well for most cases. Two-compartment models provide better details, but have higher parameter uncertainties. The absorption duration can be determined directly from the model parameters and thus allow an easy comparison between the ways of administration. Furthermore, the precise site of injection for intramuscular delivery appears to make a difference in terms of the duration of the drug absorption.

Paraventricular Nucleus of the Hypothalamus Oxytocin and Incubation of Heroin Seeking

INTRODUCTION

There are numerous pharmacologic treatments for opioid use disorder (OUD), but none that directly target the underlying addictive effects of opioids. Oxytocin, a peptide hormone produced in the paraventricular nucleus (PVN) of the hypothalamus, has been investigated as a potential therapeutic for OUD. Promising preclinical and clinical results have been reported, but the brain region(s) and mechanism(s) by which oxytocin impacts reward processes remain undetermined.

METHODS

Here, we assess peripherally administered oxytocin's impacts on cued reinstatement of heroin seeking following forced abstinence and its effects on neuronal activation in the PVN and key projection regions. We also examine how designer receptors exclusively activated by designer drug (DREADD)-mediated activation or inhibition of oxytocinergic PVN neurons alters cued heroin seeking and social interaction.

RESULTS

As predicted, peripheral oxytocin administration successfully decreased cued heroin seeking on days 1 and 30 of abstinence. Oxytocin administration also led to increased neuronal activity within the PVN and the central amygdala (CeA). Activation of oxytocinergic PVN neurons with an excitatory (Gq) DREADD did not impact cued reinstatement or social interaction. In contrast, suppression with an inhibitory (Gi) DREADD reduced heroin seeking on abstinence day 30 and decreased time spent interacting with a novel conspecific.

DISCUSSION

These findings reinforce oxytocin's therapeutic potential for OUD, the basis for which may be driven in part by increased PVN-CeA circuit activity. Our results also suggest that oxytocin has distinct signaling and/or other mechanisms of action to produce these effects, as inhibition, but not activation, of oxytocinergic PVN neurons did not recapitulate the suppression in heroin seeking.

Naloxone administration by law enforcement officers in New York State (2015-2020)

BACKGROUND

The COVID-19 pandemic has amplified the need for wide deployment of effective harm reduction strategies in preventing opioid overdose mortality. Placing naloxone in the hands of key responders, including law enforcement officers who are often first on the scene of a suspected overdose, is one such strategy. New York State (NYS) was one of the first states to implement a statewide law enforcement naloxone administration program. This article provides an overview of the law enforcement administration of naloxone in NYS between 2015 and 2020 and highlights key characteristics of over 9000 opioid overdose reversal events.

METHODS

Data in naloxone usage report forms completed by police officers were compiled and analyzed. Data included 9133 naloxone administration reports by 5835 unique officers located in 60 counties across NYS. Descriptive statistics were used to examine attributes of the aided individuals, including differences between fatal and non-fatal incidents. Additional descriptive analyses were conducted for incidents in which law enforcement officers arrived first at the scene of suspected overdose. Comparisons were made to examine year-over-year trends in administration as naloxone formulations were changed. Quantitative analysis was supplemented by content analysis of officers' notes (n = 2192).

RESULTS

In 85.9% of cases, law enforcement officers arrived at the scene of a suspected overdose prior to emergency medical services (EMS) personnel. These officers assessed the likelihood of an opioid overdose having occurred based on the aided person's breathing status and other information obtained on the scene. They administered an average of 2 doses of naloxone to aided individuals. In 36.8% of cases, they reported additional administration of naloxone by other responders including EMS, fire departments, and laypersons. Data indicated the aided survived the suspected overdose in 87.4% of cases.

CONCLUSIONS

With appropriate training, law enforcement personnel were able to recognize opioid overdoses and prevent fatalities by administering naloxone and carrying out time-sensitive medical interventions. These officers provided life-saving services to aided individuals alongside other responders including EMS, fire departments, and bystanders. Further expansion of law enforcement naloxone administration nationally and internationally could help decrease opioid overdose mortality.

Comparison of intranasal and intramuscular naloxone in opioid overdoses managed by ambulance staff: a double-dummy, randomised, controlled trial

AIMS

To measure and evaluate clinical response to nasal naloxone in opioid overdoses in the pre-hospital environment.

DESIGN

Randomised, controlled, double-dummy, blinded, non-inferiority trial, and conducted at two centres.

SETTING

Participants were included by ambulance staff in Oslo and Trondheim, Norway, and treated at the place where the overdose occurred.

PARTICIPANTS

Men and women age above 18 years with miosis, rate of respiration ≤8/min, and Glasgow Coma Score <12/15 were included. Informed consent was obtained through a deferred-consent procedure.

INTERVENTION AND COMPARATOR

A commercially available 1.4 mg/0.1 mL intranasal naloxone was compared with 0.8 mg/2 mL naloxone administered intramuscularly.

MEASUREMENTS

The primary end-point was restoration of spontaneous respiration of ≥10 breaths/min within 10 minutes. Secondary outcomes included time to restoration of spontaneous respiration, recurrence of overdose within 12 hours and adverse events.

FINDINGS

In total, 201 participants were analysed in the per-protocol population. Heroin was suspected in 196 cases. With 82% of the participants being men, 105 (97.2%) in the intramuscular group and 74 (79.6%) in the intranasal group returned to adequate spontaneous respiration within 10 minutes after one dose. The estimated risk difference was 17.5% (95% CI, 8.9%-26.1%) in favour of the intramuscular group. The risk of receiving additional naloxone was 19.4% (95% CI, 9.0%-29.7%) higher in the intranasal group. Adverse reactions were evenly distributed, except for drug withdrawal reactions, where the estimated risk difference was 6.8% (95% CI, 0.2%-13%) in favour of the intranasal group in a post hoc analysis.

CONCLUSION

Intranasal naloxone (1.4 mg/0.1 mL) was less efficient than 0.8 mg intramuscular naloxone for return to spontaneous breathing within 10 minutes in overdose patients in the pre-hospital environment when compared head-to-head. Intranasal naloxone at 1.4 mg/0.1 mL restored breathing in 80% of participants after one dose and had few mild adverse reactions.

Gaps in naloxone ownership among people who inject drugs during the fentanyl wave of the opioid overdose epidemic in New York City, 2018

Background: Community distribution of naloxone, a medication that reverses opioid overdose, is an effective public health strategy to prevent overdose deaths. However, data are limited on who has naloxone during the current fentanyl wave of the opioid overdose epidemic in the United States. We aim to determine correlates of naloxone ownership among a community sample of people who inject drugs (PWID) from New York City (NYC). Methods: Data were drawn from the National HIV Behavioral Surveillance Study among PWID. Participants were recruited via respondent-driven sampling. Eligible participants completed an interviewer-administered survey. Log-linked Poisson regression was used to determine adjusted prevalence ratios (aPR) and 95% confidence intervals (CIs) current naloxone ownership. Results: Of 503 PWID, 60% currently owned naloxone. In the past 12 months, 74% witnessed an opioid overdose and 25% experienced one. Those who experienced current homelessness were less likely to own naloxone (aPR: 0.79; 95% CI: 0.68, 0.91), as were those who had been recently incarcerated (aPR: 0.83; 95% CI: 0.71, 0.97). Respondents who reported recent known or possible fentanyl use were more likely to own naloxone (aPR: 1.23; 95% CI: 1.07, 1.43) as were those who experienced an opioid overdose in the past 12 months (aPR: 1.33; 95% CI: 1.15, 1.53). Conclusions: The prevalence of naloxone ownership among PWID in NYC was high, potentially due to widespread community naloxone distribution programs; however, gaps in naloxone ownership existed. Interventions that further ease access to naloxone, such as reclassifying naloxone as an over-the-counter medication and making it available "off the shelf," should be considered. More research is needed to identify barriers to access, uptake, and sustained possession within this group to maximize the impact of naloxone distribution during the ongoing fentanyl wave of the opioid overdose epidemic.

Rapid Absorption of Naloxone from Eye Drops

Naloxone as emergency treatment for opioid overdosing can be administered via several routes. However, the available administration methods are invasive or may be associated with incomplete or slow naloxone absorption. We evaluated pharmacokinetics and local tolerance of naloxone ocular drops in healthy beagle dogs. Naloxone administration as eye drops produced fast absorption with time to maximum plasma concentration (t_max) achieved in 14 to 28 min, high plasma exposure (C_max 10.3 ng/mL to 12.7 ng/mL), and good bioavailability (41% to 56%). No signs of ocular irritability were observed in the scored ocular tolerability parameters, and the reactions of dogs suggesting immediate ocular discomfort after the dosing were sporadic and short lasting. Slight and transient increase in the intraocular pressure and transient decrease in the tear production were recorded. The results suggest that eye drops may provide a fast and an effective non-invasive route for naloxone administration to reverse opioid overdosing, and clinical studies in the human are warranted.

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.

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.

Take-Home Naloxone and the Prevention of Deaths from Heroin Overdose: Pursuing Strong Science, Fuller Understanding, Greater Impact

BACKGROUND AND CONTEXT

Realization of the life-saving potential of "take-home naloxone" has been a personal journey, but it has also been a collective journey. It has been a story of individual exploration and growth, and also a story of changes at a societal level. "Take-home naloxone" has matured since its first conceptualization a quarter of a century ago. It required recognition of the enormous burden of deaths from drug overdose (particularly heroin and other opioids), and also realization of critical clusterings (such as post-release from prison). It also required realization that, since many overdose deaths are witnessed, we can potentially prevent many deaths by mobilizing drug users themselves, their families, and the wider caring community to act as intervention workforce to give life-saving interim emergency care. Summary of Scope: This article explores 5 areas (many illustrations UK-based where the author works): firstly, the need for strong science; secondly, our improved understanding of opioid overdose and deaths; thirdly, the search for greater impact from our policies and interventions; fourthly, developing better forms of naloxone; and fifthly, examining the challenges still to be addressed.

KEY MESSAGES

"Take-home naloxone" is an exemplar of harm reduction with potential global impact - drug policy and practice for the public good. However, "having the potential" is not good enough - there needs to be actual implementation. This will be easier once the component parts of "take-home naloxone" are improved (better naloxone products, better training aids, revised legislation, and explicit funding support). Many improvements are already possible, but we hesitate about implementation. It is our responsibility to drive progress faster. With "take-home naloxone," we can be proud of what we have achieved, but we must also be humble about how much more we still need to do.

UNDERSTANDING PREFERENCES FOR TYPE OF TAKE-HOME NALOXONE DEVICE: INTERNATIONAL QUALITATIVE ANALYSIS OF THE VIEWS OF PEOPLE WHO USE OPIOIDS

Background

Take-home naloxone (THN) is provided to non-medically trained people to reverse potential opioid overdoses. There is an increasing range of effective intramuscular (IM) and intranasal (IN) naloxone devices and this paper explores the types preferred by people who use opioids, using consumer behaviour literature to interpret the findings.

Methods

Data derive from two unconnected qualitative studies involving audio-recorded semi-structured interviews. Study 1 was conducted in the United States (n=21 users of non-medical/illicit opioids). Study 2 was conducted in Australia (n=42 users of non-medical/illicit or prescribed opioids).

Findings

Most participants preferred IN naloxone. Preferences were based on the ease, speed, safety and comfort of each device and underpinned by accounts of overdose revivals as being very rushed and frightening situations. Preferences related to complex interactions between the naloxone device ('product'); the knowledge, skills, experience and attitudes of the lay responder ('consumer'), and when, where and how naloxone was to be used ('usage situation').

Conclusions

THN programs should offer choice of device when possible and nasal naloxone if resources permit. Asking people which devices they prefer and why and treating them as valued consumers of naloxone products can generate insights that improve future naloxone technology and increase THN uptake and usage.

A Study on the Efficacy of a Naloxone Training Program

Introduction: The use of naloxone to reverse a potentially fatal opioid overdose is a harm reduction strategy that reduces mortality and increases the potential for referral to substance use treatment for affected individuals. In the setting of outreach performed by a street medicine team, we aimed to determine the effectiveness of an educational intervention involving distribution of naloxone accompanied by a brief instructive session about opioids, opioid overdose, and medication administration.

Methods: Our street medicine outreach team distributed 200 naloxone kits to clinicians and volunteers involved in caring for patients on ‘street rounds,’ as well as in shelters, soup kitchens, and street medicine clinic settings. Those receiving a naloxone kit engaged in a peer-reviewed presentation on how to safely use the medication to reverse a potentially fatal opioid overdose. The study team developed and administered a pre- and post-survey of 10 multiple choice questions on material covered in the educational training. The pre- and post-survey scores were compared to assess the effectiveness of implementing this training. Results were stratified by participant gender and age group.

Results: Out of the 200 participants, six were excluded from the analysis due to completely missing data from one or both surveys. The mean age of participants was 40.2±12.5 years; 120 (65.6%) were female, 62 (33.9%) were male, and 1 (0.6%) identified as nonbinary. Every survey question had an increase in correct responses from pre-survey to post-survey (identified by an increase in the percentage of correct responses). The mean survey total score increased from 5.5±1.6 to 7.5±1.3. Within the sample of 194, the mean difference in scores from pre-survey to post-survey was 2.02 points (95% CI [1.77, 2.26]), p<0.0001. Males had a mean increase in the total score from 5.6±1.8 to 7.4±1.1. Females had a mean increase in the total score from 5.5±1.5 to 7.5±1.3. The difference in total scores in males was 1.89 points (95% CI [1.42, 2.35]), p<0.0001, and in females was 2.02 points (95% CI [1.71, 2.32]), p<0.0001. Post-test scores improved in all age groups.

Conclusion: The educational training on opioids, opioid overdose, and the use of naloxone was an effective adjunct to naloxone kit distribution to volunteers and clinicians caring for people experiencing homelessness.

Lifesaving Medications Use By Athletic Trainers

The athletic trainer's (AT) emergency management skill set requires competency in the delivery of basic lifesaving medications. Some lifesaving medications have been a part of athletic training practice for decades, but that list has grown as ATs' practice setting has expanded - increasing the types of em ergent conditions that the AT may have to treat. The 2020 CAATE curricular standards require athletic training students be trained to administer the following: supplemental oxygen, nitroglycerine, low dose aspirin, bronchodilators, epinephrine using automated injection device, glucagon, and naloxone. Clinically, the conditions treated by these medications can be categorized as follows: cardiac, respiratory, hypoglycemia, or anaphylaxis. All ATs should know the indications, contraindications, administration methods, and the details of patient monitoring for each medication. Generally, these medications are safe, have clear indications for use, and few contraindications. While ATs are trained to administer these medications, they must consider state laws and local policies.

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".

The Effect of Overdose Education and Naloxone Distribution: An Umbrella Review of Systematic Reviews

Background. Opioids contribute to more than 60 000 deaths annually in North America. While the expansion of overdose education and naloxone distribution (OEND) programs has been recommended in response to the opioid crisis, their effectiveness remains unclear. Objectives. To conduct an umbrella review of systematic reviews to provide a broad-based conceptual scheme of the effect and feasibility of OEND and to identify areas for possible optimization. Search Methods. We conducted the umbrella review of systematic reviews by searching PubMed, Embase, PsycINFO, Epistemonikos, the Cochrane Database of Systematic Reviews, and the reference lists of relevant articles. Briefly, an academic librarian used a 2-concept search, which included opioid subject headings and relevant keywords with a modified PubMed systematic review filter. Selection Criteria. Eligible systematic reviews described comprehensive search strategies and inclusion and exclusion criteria, evaluated the quality or risk of bias of included studies, were published in English or French, and reported data relevant to either the safety or effectiveness of OEND programs, or optimal strategies for the management of opioid overdose with naloxone in out-of-hospital settings. Data Collection and Analysis. Two reviewers independently extracted study characteristics and the quality of included reviews was assessed in duplicate with AMSTAR-2, a critical appraisal tool for systematic reviews. Review quality was rated critically low, low, moderate, or high based on 7 domains: protocol registration, literature search adequacy, exclusion criteria, risk of bias assessment, meta-analytical methods, result interpretation, and presence of publication bias. Summary tables were constructed, and confidence ratings were provided for each outcome by using a previously modified version of the Royal College of General Practitioners' clinical guidelines. Main Results. Six systematic reviews containing 87 unique studies were included. We found that OEND programs produce long-term knowledge improvement regarding opioid overdose, improve participants' attitudes toward naloxone, provide sufficient training for participants to safely and effectively manage overdoses, and effectively reduce opioid-related mortality. High-concentration intranasal naloxone (> 2 mg/mL) was as effective as intramuscular naloxone at the same dose, whereas lower-concentration intranasal naloxone was less effective. Evidence was limited for other naloxone formulations, as well as the need for hospital transport after overdose reversal. The preponderance of evidence pertained persons who use heroin. Author's Conclusions. Evidence suggests that OEND programs are effective for reducing opioid-related mortality; however, additional high-quality research is required to optimize program delivery. Public Health Implications. Community-based OEND programs should be implemented widely in high-risk populations.

The pharmacokinetic interaction between nasally administered naloxone and the opioid remifentanil in human volunteers

Purpose

Remifentanil has been shown to increase the bioavailability of nasally administered naloxone. The aim of this study was to explore the nature of this observation.

Methods

We analysed samples from three pharmacokinetic studies to determine the serum concentrations of naloxone-3-glucuronide (N3G), the main metabolite of naloxone, with or without exposure to remifentanil. To enable direct comparison of the three studies, the data are presented as metabolic ratios (ratio of metabolite to mother substance, N3G/naloxone) and dose-corrected values of the area under the curve and maximum concentration (Cmax).

Results

Under remifentanil exposure, the time to maximum concentration (Tmax) for N3G was significantly higher for intranasal administration of 71 min compared to intramuscular administration of 40 min. The dose-corrected Cmax of N3G after intranasal administration of naloxone under remifentanil exposure was significantly lower (4.5 ng/mL) than in subjects not exposed to remifentanil (7.8–8.4 ng/mL). The metabolic ratios after intranasal administration rose quickly after 30–90 min and were 2–3 times higher at 360 min compared to intravenous and intramuscular administration. Remifentanil exposure resulted in a much slower increase of the N3G/naloxone ratio after intranasal administration compared to intranasal administration with the absence of remifentanil. After remifentanil infusion was discontinued, this effect gradually diminished. From 240 min there was no significant difference between the ratios observed after intranasal naloxone administration.

Conclusion

Remifentanil increases the bioavailability of naloxone after nasal administration by reducing the pre-systemic metabolism of the swallowed part of the nasal dose.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00228-021-03190-1.

Rapid systemic uptake of naloxone after intranasal administration in children

BACKGROUND

Naloxone has a high affinity for the µ-opioid receptor and acts as a competitive antagonist, thus reversing the effects of opioids. Naloxone is often administrated intravenously, but there is a growing interest in the intranasal route in treating patients with opioid overdose, and in reversing effects after therapeutic use of opioids. As administration is painless and no intravenous access is needed, the intranasal route is especially useful in children.

AIM

The aim of this study was to investigate the uptake of naloxone 0.4 mg/ml during the first 20 min after administration as a nasal spray in a pediatric population, with special focus on the time to achieve maximum plasma concentration.

METHODS

Twenty children, 6 months-10 years, were included in the study. The naloxone dose administered was 20 µg/kg, maximum 0.4 mg, divided into repeated doses of 0.1 ml in each nostril. Venous blood samples were collected at 5, 10, and 20 min after the end of administration.

RESULTS

All patients had quantifiable concentrations of naloxone in venous blood at 5 min, and within 20 min, peak concentration had been reached in more than half of the children. At 20 min after intranasal administration, the plasma naloxone concentrations were within the range of 2-6 nanogram/ml.

CONCLUSION

This study confirms the clinical experience that the rapid effect of naloxone after intranasal administration in children was reflected in rapid systemic uptake to achieve higher peak plasma concentrations than previously reported in adults.

Overcoming the challenges of developing an intranasal diazepam rescue therapy for the treatment of seizure clusters

Seizure clusters must be treated quickly and effectively to prevent progression to prolonged seizures and status epilepticus. Rescue therapy for seizure clusters has focused on the use of benzodiazepines. Although intravenous benzodiazepine administration is the primary route in hospitals and emergency departments, seizure clusters typically occur in out‐of‐hospital settings, where a more portable product that can be easily administered by nonmedical caregivers is needed. Thus, other methods of administration have been examined, including rectal, intranasal, intramuscular, and buccal routes. Following US Food and Drug Administration (FDA) approval in 1997, rectal diazepam became the mainstay of out‐of‐hospital treatment for seizure clusters in the United States. However, social acceptability and consistent bioavailability present limitations. Intranasal formulations have potential advantages for rescue therapies, including ease of administration and faster onset of action. A midazolam nasal spray was approved by the FDA in 2019 for patients aged 12 years or older. In early 2020, the FDA approved a diazepam nasal spray for patients aged 6 years or older, which has a different formulation than the midazolam nasal product and enhances aspects of bioavailability. Benzodiazepines, including diazepam, present significant challenges in developing a suitable intranasal formulation. Diazepam nasal spray contains dodecyl maltoside (DDM) as an absorption enhancer and vitamin E to increase solubility in an easy‐to‐use portable device. In a Phase 1 study, absolute bioavailability of the diazepam nasal spray was 97% compared with intravenous diazepam. Subsequently, the nasal spray demonstrated less variability in bioavailability than rectal gel (percentage of geometric coefficient of variation of area under the curve = 42%–66% for diazepam nasal spray compared with 87%–172% for rectal gel). The diazepam nasal spray safety profile is consistent with that expected for rectal diazepam, with low rates of nasal discomfort (≤6%). To further improve the efficacy of rescue therapy, investigation of novel intranasal benzodiazepine formulations is underway.

Systematic Structure-Based Virtual Screening Approach to Antibody Selection and Design of a Humanized Antibody against Multiple Addictive Opioids without Affecting Treatment Agents Naloxone and Naltrexone

Opioid drug use, especially heroin, is known as a growing national crisis in America. Heroin itself is a prodrug and is converted to the most active metabolite 6-monoacetylmorphine (6-MAM) responsible for the acute toxicity of heroin and then to a relatively less-active metabolite morphine responsible for the long-term toxicity of heroin. Monoclonal antibodies (mAbs) are recognized as a potentially promising therapeutic approach in the treatment of opioid use disorders (OUDs). Due to the intrinsic challenges of discovering an mAb against multiple ligands, here we describe a general, systematic structure-based virtual screening and design approach which has been used to identify a known anti-morphine antibody 9B1 and a humanized antibody h9B1 capable of binding to multiple addictive opioids (including 6-MAM, morphine, heroin, and hydrocodone) without significant binding with currently available OUD treatment agents naloxone, naltrexone, and buprenorphine. The humanized antibody may serve as a promising candidate for the treatment of OUDs. The experimental binding affinities reasonably correlate with the computationally predicted binding free energies. The experimental activity data strongly support the computational predictions, suggesting that the systematic structure-based virtual screening and humanization design protocol is reliable. The general, systematic structure-based virtual screening and design approach will be useful for many other antibody selection and design efforts in the future.

A qualitative study of repeat naloxone administrations during opioid overdose intervention by people who use opioids in New York City

BACKGROUND

Take-home naloxone (THN) kits have been designed to provide community members (including people who use drugs, their families and/or significant others) with the necessary resources to address out-of-hospital opioid overdose events. Kits typically include two doses of naloxone. This 'twin-pack' format means that lay responders need information on how to use each dose. Advice given tends to be based on dosage algorithms used by medical personnel. However, little is currently known about how and why people who use drugs, acting as lay responders, decide to administer the second dose contained within single THN kits. The aim of this article is to explore this issue.

METHODS

Data were generated from a qualitative semi-structured interview study that was embedded within a randomised controlled trial examining the risks and benefits of Overdose Education and Naloxone Distribution (OEND) training in New York City (NYC). Analysis for this article focuses upon the experiences of 22 people who use(d) opioids and who provided repeat naloxone administrations (RNA) during 24 separate overdose events. The framework method of analysis was used to compare the time participants believed had passed between each naloxone dose administered ('subjective response interval') with the 'recommended response interval' (2-4 minutes) given during OEND training. Framework analysis also charted the various reasons and rationale for providing RNA during overdose interventions.

RESULTS

When participants' subjective response intervals were compared with the recommended response interval for naloxone dosing, three different time periods were reported for the 24 overdose events: i. 'two doses administered in under 2 minutes' (n = 10); ii. 'two doses administered within 2-4 minutes' (n = 7), and iii. 'two doses administered more than 4 minutes apart' (n = 7). A variety of reasons were identified for providing RNA within each of the three categories of response interval. Collectively, reasons for RNA included panic, recognition of urgency, delays in retrieving naloxone kit, perceptions of recipients' responsiveness/non-responsiveness to naloxone, and avoidance of Emergency Response Teams (ERT).

CONCLUSION

Findings suggest that decision-making processes by people who use opioids regarding how and when to provide RNA are influenced by factors that relate to the emergency event. In addition, the majority of RNA (17/24) occurred outside of the recommended response interval taught during OEND training. These findings are discussed in terms of evidence-based intervention and 'evidence-making intervention' with suggestions for how RNA guidance may be developed and included within future/existing models of OEND training.

Prehospital Naloxone and Emergency Department Adverse Events: A Dose-Dependent Relationship

BACKGROUND

The purpose of this study was to evaluate prehospital and emergency department (ED) interventions and outcomes of patients who received prehospital naloxone for a suspected opioid overdose.

OBJECTIVES

The primary objective was to evaluate if the individual dose, individual route, total dose, number of prehospital naloxone administrations, or occurrence of a prehospital adverse event (AE) were associated with the occurrence of AEs in the ED. Secondary objectives included a subset analysis of patients who received additional naloxone while in the ED, or were admitted to an intensive care or step-down unit (ICU).

METHODS

This was a retrospective, observational chart review of adult patients who received prehospital naloxone and were transported by ambulance to a suburban academic tertiary care center between 2014 and 2017. Descriptive, univariate, and multivariate statistics were used, with p < 0.05 indicating significance.

RESULTS

There were 513 patients included in the analysis, with a median age of 29 years, and median total prehospital naloxone dose of 2 mg. An increasing number of prehospital naloxone doses, an occurrence of a prehospital AE, and a route of administration other than intranasally for the first dose of prehospital naloxone were significantly associated with an increased likelihood of an ED AE. Patients who received < 2 mg of prehospital naloxone had the least likelihood of being admitted to an ICU, whereas patients who received at least 6 mg had a dramatically increased likelihood of ICU admission.

CONCLUSIONS

Our results suggest that an increasing number of prehospital naloxone doses was significantly associated with an increased likelihood of an ED adverse event.

A review of performance assessment tools for rescuer response in opioid overdose simulations and training programs

Since the 1990s, more than 600 overdose response training and education programs have been implemented to train participants to respond to an opioid overdose in the United States. Given this substantial investment in overdose response training, valid assessment of a potential rescuers' proficiency in responding to an opioid overdose is important. The aim of this article is to review the current state of the literature on outcome measures utilized in opioid overdose response training. Thirty-one articles published between 2014 and 2020 met inclusion criteria. The reviewed articles targeted laypersons, healthcare providers, and first responders. The assessment tools included five validated questionnaires, fifteen non-validated questionnaires, and nine non-validated simulation-based checklists (e.g., completion of critical tasks and time to completion). Validated multiple choice knowledge assessment tools were commonly used to assess the outcomes of training programs. It is unknown how scores on these assessment tools may correlate with actual rescuer performance responding to an overdose. Seven studies reported ceiling effects most likely attributed to participants' background medical knowledge or experience. The inclusion of simulation-based outcome measures of performance, including the commission of critical errors and the time to naloxone administration, provides better insight into rescuer skill proficiency.

NTNU intranasal naloxone trial (NINA-1) study protocol for a double-blind, double-dummy, non-inferiority randomised controlled trial comparing intranasal 1.4 mg to intramuscular 0.8 mg naloxone for prehospital use

INTRODUCTION

Intranasal (IN) naloxone is widely used to treat opioid overdoses. The advantage of nasal administration compared with injection lies in its suitability for administration by lay people as it is needless. Approved formulations of nasal naloxone with bioavailability of approximately 50% have only undergone trials in healthy volunteers, while off-label nasal sprays with low bioavailability have been studied in patients. Randomised clinical trials are needed to investigate efficacy and safety of approved IN naloxone in patients suffering overdose. This study investigates whether the administration of 1.4 mg naloxone in 0.1 mL per dose is non-inferior to 0.8 mg intramuscular injection in patients treated for opioid overdose.

METHODS AND ANALYSIS

Sponsor is the Norwegian University of Science and Technology. The study has been developed in collaboration with user representatives. The primary endpoint is the restoration of spontaneous respiration≥10 breaths/min based on a sample of 200 opioid overdose cases. Double-dummy design ensures blinding, which will be maintained until the database is locked.

ETHICS AND DISSEMINATION

The study was approved by the Norwegian Medicines Agency and Regional Ethics Committees (REC: 2016/2000). It adheres to the Good Clinical Practice guidelines as set out by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use.Informed consent will be sought through a differentiated model. This allows for deferred consent after inclusion for patients who have regained the ability to consent. Patients who are unable to consent prior to discharge by emergency services are given written information and can withdraw at a later date in line with user recommendations. Metadata will be published in the Norwegian University of Science and Technology Open repository. Deidentified individual participant data will be made available to recipients conditional of data processor agreement being entered.

TRIAL REGISTRATION NUMBERS

EudraCT Registry (2016-004072-22) and Clinicaltrials.gov Registry (NCT03518021).

Medical emergency kits in ambulatory care clinics

Implementation and staff perceptions of usability and feasibility.

A pilot study to compare virtual reality to hybrid simulation for opioid-related overdose and naloxone training

BACKGROUND

In the midst of the international opioid-related overdose (OOD) crisis, appropriate naloxone training is needed by both healthcare professionals and community members to better leverage its life-saving potential.

OBJECTIVE

Pilot the use of a virtual reality simulation for training student nurses to identify signs and symptoms of an OOD, properly administer intranasal naloxone, and provide immediate recovery care after revival.

DESIGN

This quasi-experimental pretest-posttest study evaluated knowledge and attitudes towards intervening during an opioid-related overdose among student nurses before and after participating in a traditional hybrid simulation or virtual reality simulation.

SETTING

A medium sized urban university's school of nursing in the Northeastern United States.

PARTICIPANTS

Fifty (N = 50) senior Bachelor of Nursing Science (BSN) students.

METHODS

Knowledge and attitudes were assessed using the Opioid Overdose Knowledge Scale (OOKS) and Opioid Overdose Attitudes Scale (OOAS). Students completed measures 3 weeks prior to training and 3 weeks after. Appropriate t-tests evaluated changes in OOAS and OOKS scores both within and between training groups (e.g. hybrid simulation compared to virtual reality).

RESULTS

Sample characteristics were well balanced in both the hybrid simulation group (n = 31) and virtual reality group (n = 19). There were no statistically significant differences in average OOKS and OOAS scores at baseline or at follow up between those receiving hybrid simulation or the virtual reality training. All participants' attitudes scores decreased from baseline to follow up by <2 points. However, there was no difference in the change in knowledge scores between the training groups.

CONCLUSIONS

Individuals participating in the virtual reality simulation had similar knowledge retention and attitudes towards responding during an opioid-related overdose and administering intranasal naloxone when compared to individuals participating in hybrid simulation. The lack of significant findings between training groups indicates that the mobile virtual reality training is comparable to the in-person hybrid simulation for training nursing students to appropriately administer naloxone to reverse OOD and provide immediate recovery care after revival.

Protocol for a multi-site study of the effects of overdose prevention education with naloxone distribution program in Skåne County, Sweden

BACKGROUND

Continuously high rates of overdose deaths in Sweden led to the decision by the Skåne County to initiate the first regional take-home naloxone program in Sweden. The project aims to study the effect of overdose prevention education and naloxone distribution on overdose mortality in Skåne County. Secondary outcome measures include non-fatal overdoses and overdose-related harm in the general population, as well as cohort-specific effects in study participants regarding overdoses, mortality and retention in naloxone program.

METHODS

Implementation of a multi-site train-the-trainer cascade model was launched in June 2018. Twenty four facilities, including opioid substitution treatment units, needle exchange programs and in-patient addiction units were included for the first line of start-up, aspiring to reach a majority of individuals at-risk within the first 6 months. Serving as self-sufficient naloxone hubs, these units provide training, naloxone distribution and study recruitment. During 3 years, questionnaires are obtained from initial training, follow up, every sixth month, and upon refill. Estimated sample size is 2000 subjects. Naloxone distribution rates are reported, by each unit, every 6 months. Medical diagnoses, toxicological raw data and data on mortality and cause of death will be collected from national and regional registers, both for included naloxone recipients and for the general population. Data on vital status and treatment needs will be collected from registers of emergency and prehospital care.

DISCUSSION

Despite a growing body of literature on naloxone distribution, studies on population effect on mortality are scarce. Most previous studies and reports have been uncontrolled, thus not being able to link naloxone distribution to survival, in relation to a comparison period. As Swedish registers present the opportunity to monitor individuals and entire populations over time, conditions for conducting systematic follow-ups in the Swedish population are good, serving the opportunity to study the impact of large scale overdose prevention education and naloxone distribution and thus fill the knowledge gap.

TRIAL REGISTRATION

Naloxone Treatment in Skåne County - Effect on Drug-related Mortality and Overdose-related Complications, NCT03570099, registered on 26 June 2018.

Endogenous opiates and behavior: 2017

This paper is the fortieth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2017 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Take-Home Naloxone for the Emergency Interim Management of Opioid Overdose: The Public Health Application of an Emergency Medicine

Naloxone is a well-established essential medicine for the treatment of life-threatening heroin/opioid overdose in emergency medicine. Over two decades, the concept of 'take-home naloxone' has evolved, comprising pre-provision of an emergency supply to laypersons likely to witness an opioid overdose (e.g. peers and family members of people who use opioids as well as non-medical personnel), with the recommendation to administer the naloxone to the overdose victim as interim care while awaiting an ambulance. There is an urgent need for more widespread naloxone access considering the growing problem of opioid overdose deaths, accounting for more than 100,000 deaths worldwide annually. Rises in mortality are particularly sharp in North America, where the ongoing prescription opioid problem is now overlaid with a rapid growth in overdose deaths from heroin and illicit fentanyl. Using opioids alone is dangerous, and the mortality risk is clustered at certain times and contexts, including on prison release and discharge from hospital and residential care. The provision of take-home naloxone has required the introduction of new legislation and new naloxone products. These include pre-filled syringes and auto-injectors and, crucially, new concentrated nasal sprays (four formulations recently approved in different countries) with speed of onset comparable to intramuscular naloxone and relative bioavailability of approximately 40-50%. Choosing the right naloxone dose in the fentanyl era is a matter of ongoing debate, but the safety margin of the approved nasal sprays is superior to improvised nasal kits. New legislation in different countries permits over-the-counter sales or other prescription-free methods of provision. However, access remains uneven with take-home naloxone still not provided in many countries and communities, and with ongoing barriers contributing to implementation inertia. Take-home naloxone is an important component of the response to the global overdose problem, but greater commitment to implementation will be essential, alongside improved affordable products, if a greater impact is to be achieved.

Effect of Intranasal vs Intramuscular Naloxone on Opioid Overdose: A Randomized Clinical Trial

IMPORTANCE

Previous unblinded clinical trials suggested that the intranasal route of naloxone hydrochloride was inferior to the widely used intramuscular route for the reversal of opioid overdose.

OBJECTIVE

To test whether a dose of naloxone administered intranasally is as effective as the same dose of intramuscularly administered naloxone in reversing opioid overdose.

DESIGN, SETTING, AND PARTICIPANTS

A double-blind, double-dummy randomized clinical trial was conducted at the Uniting Medically Supervised Injecting Centre in Sydney, Australia. Clients of the center were recruited to participate from February 1, 2012, to January 3, 2017. Eligible clients were aged 18 years or older with a history of injecting drug use (n = 197). Intention-to-treat analysis was performed for all participants who received both intranasal and intramuscular modes of treatment (active or placebo).

INTERVENTIONS

Clients were randomized to receive 1 of 2 treatments: (1) intranasal administration of naloxone hydrochloride 800 μg per 1 mL and intramuscular administration of placebo 1 mL or (2) intramuscular administration of naloxone hydrochloride 800 μg per 1 mL and intranasal administration of placebo 1 mL.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was the need for a rescue dose of intramuscular naloxone hydrochloride (800 μg) 10 minutes after the initial treatment. Secondary outcome measures included time to adequate respiratory rate greater than or equal to 10 breaths per minute and time to Glasgow Coma Scale score greater than or equal to 13.

RESULTS

A total of 197 clients (173 [87.8%] male; mean [SD] age, 34.0 [7.82] years) completed the trial, of whom 93 (47.2%) were randomized to intramuscular naloxone dose and 104 (52.8%) to intranasal naloxone dose. Clients randomized to intramuscular naloxone administration were less likely to require a rescue dose of naloxone compared with clients randomized to intranasal naloxone administration (8 [8.6%] vs 24 [23.1%]; odds ratio, 0.35; 95% CI, 0.15-0.66; P = .002). A 65% increase in hazard (hazard ratio, 1.65; 95% CI, 1.21-2.25; P = .002) for time to respiratory rate of at least 10 and an 81% increase in hazard (hazard ratio, 1.81; 95% CI, 1.28-2.56; P = .001) for time to Glasgow Coma Scale score of at least 13 were observed for the group receiving intranasal naloxone compared with the group receiving intramuscular naloxone. No major adverse events were reported for either group.

CONCLUSIONS AND RELEVANCE

This trial showed that intranasally administered naloxone in a supervised injecting facility can reverse opioid overdose but not as efficiently as intramuscularly administered naloxone can, findings that largely replicate those of previous unblinded clinical trials. These results suggest that determining the optimal dose and concentration of intranasal naloxone to respond to opioid overdose in real-world conditions is an international priority.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN12611000852954.

Treating gambling disorder with as needed administration of intranasal naloxone: a pilot study to evaluate acceptability, feasibility and outcomes

BACKGROUND AND AIM

There is growing interest in the use of medication-assisted treatments for gambling disorder (GD). Opioid receptor antagonists are hypothesised to blunt the craving associated with gambling. This study was designed to assess the feasibility of using an intranasal naloxone spray to treat GD.

DESIGN

An 8-week, open-label, uncontrolled pilot study.

SETTING

A single study site in the capital region of Finland.

SUBJECTS

Twenty problem gamblers (nine men) were randomised into two groups. Group A (n=10) took one dose into one nostril (2 mg naloxone), as needed, with a maximum of 4 doses/day (max. 8 mg/day). Group B (n=10) took one dose into each nostril (4 mg naloxone) as needed, with a maximum of 4 doses/day (max. 16 mg/day).

INTERVENTION

Naloxone hydrochloride nasal spray.

MEASURES

Acceptability and feasibility of the intervention were assessed. Use of study medication, adverse events, gambling frequency and gambling expenditure were recorded in a mobile diary. Problem gambling: South Oaks Gambling Screen (SOGS), depressive symptoms: Beck Depression Inventory (BDI) and alcohol use: Alcohol Use Disorders Identification Test were recorded.

RESULTS

Study completion rate was 90%. Acceptability and feasibility scores were high. Group B used intranasal naloxone more frequently than group A, and consequently used more naloxone. No serious adverse events were reported. The postintervention SOGS scores were lower (median=4 (IQR=3.75) versus preintervention scores (median=12 (IQR=4.75)). Depressive symptoms were reduced during the trial (preintervention BDI median=9, IQR=9 vs postintervention BDI median=6, IQR=6).

CONCLUSIONS

The acceptability and feasibility of using intranasal naloxone were high, and no serious adverse events were reported. Preliminary results suggest mixed results in terms of gambling behaviour (ie, reduced frequency but not expenditure) and decreased depressive symptoms.

TRIAL REGISTRATION NUMBER

EudraCT2016-001828-56.

Intranasal naloxone rapidly occupies brain mu-opioid receptors in human subjects

Nasal spray formulations of naloxone, a mu-opioid receptor (MOR) antagonist, are currently used for the treatment of opioid overdose. They may have additional therapeutic utility also in the absence of opioid agonist drugs, but the onset and duration of action at brain MORs have been inadequately characterized to allow such projections. This study provides initial characterization of brain MOR availability at high temporal resolution following intranasal (IN) naloxone administration to healthy volunteers in the absence of a competing opioid agonist. Fourteen participants were scanned twice using positron emission tomography (PET) and [¹¹C]carfentanil, a selective MOR agonist radioligand. Concentrations of naloxone in plasma and MOR availability (relative to placebo) were monitored from 0 to 60 min and at 300-360 min post naloxone. Naloxone plasma concentrations peaked at ~20 min post naloxone, associated with slightly delayed development of brain MOR occupancy (half of peak occupancy reached at ~10 min). Estimated peak occupancies were 67 and 85% following 2 and 4 mg IN doses, respectively. The estimated half-life of occupancy disappearance was ~100 min. The rapid onset of brain MOR occupancy by IN naloxone, evidenced by the rapid onset of its action in opioid overdose victims, was directly documented in humans for the first time. The employed high temporal-resolution PET method establishes a model that can be used to predict brain MOR occupancy from plasma naloxone concentrations. IN naloxone may have therapeutic utility in various addictions where brain opioid receptors are implicated, such as gambling disorder and alcohol use disorder.

Prepacked naloxone administration for suspected opioid overdose in the era of illicitly manufactured fentanyl: a retrospective study of regional poison center data

Background: Prepacked naloxone kits (PNKs) are frequently used to reverse opioid intoxication. It is unknown if the presence of illicitly manufactured fentanyl and its analogs (IMFs) in heroin supply is affecting the PNK doses given by laypersons. We investigated the trend of PNK dose administered to reverse opioid toxicity in suspected/undifferentiated opioid intoxication.Methods: We retrospectively reviewed PNK administrations reported to the Maryland Poison Center between 1 January 2015 and 15 October 2017. Primary outcome was the mean PNK dose administered to reverse opioid-induced central nervous system and ventilatory depression. Secondary outcomes included the reversal rate of opioid toxicity, patient disposition, and survival rate.Results: Our analysis involved 1139 PNK administrations. The mean age of subjects was 34.3 years; 68.8% (n = 781) were male. Ventilatory depression was present in 98.2% (n = 958) of cases, and 97% (n = 1097) were unresponsive. Law enforcement administered the majority of PNK (91.0%; n = 1035); the primary route was intranasal (97.9%; n = 1051). Toxicity was reversed in 79.2% (n = 886) of overdose victims after a mean PNK dose of 3.12 mg. EMS personnel gave 291 subjects additional naloxone (mean: 2.2 mg), reversing opioid toxicity in 94.2% (n = 254). Between 2015 and 2017, the mean PNK dose increased from 2.12 to 3.63 mg (p < .0001) while the reversal rate decreased from 82.1% to 76.4% (p = .04). One hundred and eighty-two patients (15.9%) refused transport; of those transported to a hospital, 73.4% (n = 569) were treated and released and 12.4% (n = 96) required hospitalization. Ninety-six percent (n = 1092) of the subjects survived. Forty subjects were pronounced dead at the scene. Fentanyl or its analog was detected in 36 of 55 opioid-related deaths (65.5%).Conclusions: PNK administration reversed toxicity in the majority of patients with undifferentiated opioid intoxication. Between 2015 and 2017, increasing doses of PNK were administered but the reversal rate decreased. These trends are likely multifactorial, including increasing availability of IMFs.

Pharmacokinetics of a novel, approved, 1.4-mg intranasal naloxone formulation for reversal of opioid overdose-a randomized controlled trial

BACKGROUND AND AIMS

Intranasal (i.n.) naloxone is an established treatment for opioid overdose. Anyone likely to witness an overdose should have access to the antidote. We aimed to determine whether an i.n. formulation delivering 1.4 mg naloxone hydrochloride would achieve systemic exposure comparable to that of 0.8 mg intramuscular (i.m.) naloxone.

DESIGN

Open, randomized four-way cross-over trial.

SETTING

Clinical Trials Units in St Olav's Hospital, Trondheim and Rikshospitalet, Oslo, Norway.

PARTICIPANTS

Twenty-two healthy human volunteers, 10 women, median age = 25.8 years.

INTERVENTION AND COMPARATOR

One and two doses of i.n. 1.4 mg naloxone compared with i.m. 0.8 mg and intravenous (i.v.) 0.4 mg naloxone.

MEASUREMENTS

Quantification of plasma naloxone was performed by liquid chromatography tandem mass spectrometry. Pharmacokinetic non-compartment analyses were used for the main analyses. A non-parametric pharmacokinetic population model was developed for Monte Carlo simulations of different dosing scenarios.

FINDINGS

Area under the curve from administration to last measured concentration (AUC_0-last ) for i.n. 1.4 mg and i.m. 0.8 mg were 2.62 ± 0.94 and 3.09 ± 0.64 h × ng/ml, respectively (P = 0.33). Maximum concentration (C_max ) was 2.36 ± 0.68 ng/ml for i.n. 1.4 mg and 3.73 ± 3.34 for i.m. 0.8 mg (P = 0.72). Two i.n. doses showed dose linearity and achieved a C_max of 4.18 ± 1.53 ng/ml. T_max was reached after 20.2 ± 9.4 minutes for i.n. 1.4 mg and 13.6 ± 15.4 minutes for i.m. 0.8 mg (P = 0.098). The absolute bioavailability for i.n. 1.4 mg was 0.49 (±0.24), while the relative i.n./i.m. bioavailability was 0.52 (±0.25).

CONCLUSION

Intranasal 1.4 mg naloxone provides adequate systemic concentrations to treat opioid overdose compared with intramuscular 0.8 mg, without statistical difference on maximum plasma concentration, time to maximum plasma concentration or area under the curve. Simulations support its appropriateness both as peer administered antidote and for titration of treatment by professionals.

Pharmacokinetic Interaction between Naloxone and Naltrexone Following Intranasal Administration to Healthy Subjects

Naloxone (17-allyl-4,5α-epoxy-3,14-dihydroxymorphinan-6-one HCl), a μ-opioid receptor antagonist, is administered intranasally to reverse an opioid overdose but its short half-life may necessitate subsequent doses. The addition of naltrexone [17-(cyclopropylmethyl)-4,5α-epoxy-3,14-dihydroxymorphinan-6-one], another μ-receptor antagonist, which has a reported half-life of 3 1/2 hours, may extend the available time to receive medical treatment. In a phase 1 pharmacokinetic study, healthy adults were administered naloxone and naltrexone intranasally, separately and in combination. When administered with naloxone, the C _max value of naltrexone decreased 62% and the area under the concentration-time curve from time zero to infinity (AUC_0-inf) decreased 38% compared with when it was given separately; lower concentrations of naltrexone were observed as early as 5 minutes postdose. In contrast, the C _max and AUC_0-inf values of naloxone decreased only 18% and 16%, respectively, when given with naltrexone. This apparent interaction was investigated further to determine if naloxone and naltrexone shared a transporter. Neither compound was a substrate for organic cation transporter (OCT) 1, OCT2, OCT3, OCTN1, or OCTN2. There was no evidence of the involvement of a transmembrane transporter when they were tested separately or in combination at concentrations of 10 and 500 µM using Madin-Darby canine kidney II cell monolayers at pH 7.4. The efflux ratios of naloxone and naltrexone increased to six or greater when the apical solution was pH 5.5, the approximate pH of the nasal cavity; there was no apparent interaction when the two were coincubated. The importance of understanding how opioid antagonists are absorbed by the nasal epithelium is magnified by the rise in overdose deaths attributed to long-lived synthetic opioids and the realization that better strategies are needed to treat opioid overdoses.

Fighting Fire with Fire: Development of Intranasal Nalmefene to Treat Synthetic Opioid Overdose

The dramatic rise in overdose deaths linked to synthetic opioids (e.g., fentanyl, carfentanil) may require more potent, longer-duration opiate antagonists than naloxone. Both the high affinity of nalmefene at μ opiate receptors and its long half-life led us to examine the feasibility of developing an intranasal (IN) formulation as a rescue medication that could be especially useful in treating synthetic opioid overdose. In this study, the pharmacokinetic properties of IN nalmefene were compared with an intramuscular (i.m.) injection in a cohort of healthy volunteers. Nalmefene was absorbed slowly following IN administration, with a median time to reach C_max (T_max) of 2 hours. Addition of the absorption enhancer dodecyl maltoside (Intravail, Neurelis, Inc., Encinitas, CA) reduced T_max to 0.25 hour and increased C_max by ∼2.2-fold. The pharmacokinetic properties of IN nalmefene (3 mg) formulated with dodecyl maltoside has characteristics consistent with an effective rescue medication: its onset of action is comparable to an i.m. injection of nalmefene (1.5 mg) previously approved to treat opioid overdose. Furthermore, the C_max following IN administration was ∼3-fold higher than following i.m. dosing, comparable to previously reported plasma concentrations of nalmefene observed 5 minutes following a 1-mg i.v. dose. The high affinity, very rapid onset, and long half-life (>7 hours) of IN nalmefene present distinct advantages as a rescue medication, particularly against longer-lived synthetic opioids.

Comparative Human Factors Evaluation of Two Nasal Naloxone Administration Devices: NARCAN® Nasal Spray and Naloxone Prefilled Syringe with Nasal Atomizer

INTRODUCTION

Opioid overdose rescue situations are time-critical, high-stress scenarios that frequently require nonmedical first responders or bystanders to intervene and administer naloxone to avoid opioid-induced fatalities. Training nonmedical personnel to respond during such mentally constraining situations presents the human factors challenge of how best to design a safe and effective lay delivery system. This paper comparatively evaluates the ease of use of two nasal naloxone administration products: NARCAN^® Nasal Spray and a naloxone prefilled syringe with nasal atomizer (PFS-NA).

METHODS

We evaluated the use requirements and usability of NARCAN^® Nasal Spray versus a naloxone PFS-NA using a systems-oriented method. First, we determined the use requirements of different user groups. Next, we focused on constructing a human factors task analysis of both products. Finally, we conducted a comparative risk assessment of the tasks that were different between the two products.

RESULTS

Inexperienced users, such as nonmedical first responders and bystanders, are at the highest risk of incorrectly administering naloxone, particularly in high-stress emergency opioid overdose situations. The device Preparation and Medication Delivery tasks most differentiate the use of NARCAN^® Nasal Spray and a PFS-NA. The level of task complexity and number of steps within those tasks is substantially greater for a PFS-NA than for the NARCAN^® Nasal Spray.

CONCLUSIONS

NARCAN^® Nasal Spray requires fewer steps and is easier to administer than a naloxone PFS-NA. Thus, using NARCAN^® Nasal Spray should increase the likelihood that nonmedical personnel correctly deliver naloxone in time-critical, high-stress opioid overdose rescue situations.

FUNDING

ADAPT Pharma, Inc.

Comparison of the Pharmacokinetic Properties of Naloxone Following the Use of FDA-Approved Intranasal and Intramuscular Devices Versus a Common Improvised Nasal Naloxone Device

For more than a decade, first responders and the general public have been able to treat suspected opioid overdoses using an improvised nasal naloxone device (INND) constructed from a prefilled syringe containing 2 mg of naloxone (1 mg/mL) attached to a mucosal atomization device. In recent years, the U.S. Food and Drug Administration (FDA)-approved Ezvio, an autoinjector that delivers 2 mg by intramuscular injection and Narcan nasal spray (2- and 4-mg strengths; 0.1 mL/dose) for the emergency treatment of a known or suspected opioid overdose. The present study was conducted to compare the pharmacokinetics of naloxone using the FDA-approved devices (each administered once) and either 1 or 2 administrations using the INND. When naloxone was administered twice using the improvised device, the doses were separated by 2 minutes. The highest maximum plasma concentration was achieved using the 4-mg FDA-approved spray. The highest exposures at 5 minutes postdose, based on AUC values, were after administration with the autoinjector and the 4-mg FDA-approved spray; at 10, 15, and 20 minutes postdose, the latter yielded the greatest exposure. Even after 2 administrations, the INND failed to achieve naloxone plasma levels comparable to the FDA-approved devices at any time. The ease of use and higher plasma concentrations achieved using the 4-mg FDA-approved spray, compared with the INND, should be considered when deciding which naloxone device to use.

[Feedback from two French addiction centers and national survey on the intranasal naloxone (Nalscue®) in the prevention of opioid overdoses]

OBJECTIVE

France has temporarily authorized addictology centers to use a form of intranasal naloxone (Nalscue^®) to prevent opioid overdoses. The objectives of this work are to present both the characteristics of the patients included in this device in two hospitals centers and the results of the national survey on addiction center's contribution to this new risk reduction tool.

METHODS

Patient data are those requested under Nalscue^® study (inclusion period July 2016 to January 2018). The survey is an online questionnaire distributed to all addiction centers with an email address.

RESULTS

Over this period, in the two addiction centers, 370 kits (35% of the national total) were distributed to 330 patients including 312 opioid users. Of these users, 15% report injecting and 85% are poly-consumers. In 14% of the cases, a patient's relative was formed to administrate the Nalscue^®. Forty kits (30 given away, 6 lost, 4 administered) were renewed to 35 users. Of the 462 addiction centers contacted, 82 (18%) responded. Among 76 structures specialized in opioid addictions, two did not feel concerned and one had no knowledge of the antidote. Fifty-five structures were formed by the pharmaceutical firm. Nine hundred forty-seven patients (58% of the total) were included by 37 centers. Forty-four centers ordered 2458 kits and dispensed 1116 (including kits given out of study). Thirteen structures reported use of Nalscue^®.

CONCLUSION

The interest of intranasal naloxone is no longer to be demonstrated in a context of opioid overdose, but the preauthorized framework did not allow a major diffusion of the antidote within the population most at risk. Let us hope that the availability in pharmacy can promote its distribution and thus reduce the number of deaths.

Enhanced Intranasal Absorption of Naltrexone by Dodecyl Maltopyranoside: Implications for the Treatment of Opioid Overdose

Based on its high affinity for μ opiate receptors and reported half‐life after oral administration, the pharmacokinetic properties of intranasal naltrexone were examined to evaluate its potential to treat opioid overdose. This study was prompted by the marked rise in overdose deaths linked to synthetic opioids like fentanyl, which may require more potent, longer‐lived opiate antagonists than naloxone. Both the maximum plasma concentration (C_max) and the time (T_max) to reach C_max for intranasal naltrexone (4 mg) were comparable to values reported for a Food and Drug Administration‐approved 4‐mg dose of intranasal naloxone. The addition of the absorption enhancer dodecyl maltoside (Intravail) increased C_max by ∼3‐fold and reduced the T_max from 0.5 to 0.17 hours. Despite these very rapid increases in plasma concentrations of naltrexone, its short half‐life following intranasal administration (∼2.2 hours) could limit its usefulness as a rescue medication, particularly against longer‐lived synthetic opioids. Nonetheless, the ability to rapidly attain high plasma concentrations of naltrexone may be useful in other indications, including an as‐needed dosing strategy to treat alcohol use disorder.

Pharmacological Research as a Key Component in Mitigating the Opioid Overdose Crisis

The United States is experiencing an epidemic of opioid overdose deaths. Many of the recent fatalities are associated with illicitly manufactured fentanyl, which is being added to heroin and counterfeit pain pills. The crisis is further exacerbated by the emergence of an increasing number of novel synthetic opioids (NSOs), including various fentanyl analogs and non-fentanyl compounds that display potent agonist actions at the μ-opioid receptor. Importantly, most users are unaware of their exposure to fentanyl and NSOs. Stemming the tide of opioid-related fatalities will require a coordinated multidisciplinary response from policy makers, law enforcement personnel, first responders, treatment providers, family members, and scientists. To this end, basic research in pharmacology can contribute significantly to mitigating the crisis through efforts to characterize the biological effects of NSOs, discover more effective antidotes for overdose rescue, and develop safer medications for treating addiction and alleviating pain.