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

Computational screening and MM/GBSA-based MD simulation studies reveal the high binding potential of FDA-approved drugs against Cutibacterium acnes sialidase

Cutibacterium acnes is an opportunistic pathogen linked with acne vulgaris, affecting 80-90% of teenagers globally. On the leukocyte (WBCs) cell surface, the cell wall anchored sialidase in C. acnes virulence factor, catalysing the sialoconjugates into sialic acids and nutrients for C. acnes resulting in human skin inflammation. The clinical use of antibiotics for acne treatments has severe adverse effects, including microbial dysbiosis and resistance. Therefore, identifying inhibitors for primary virulence factors (Sialidase) was done using molecular docking of 1030 FDA-approved drugs. Initially, based on binding energies (ΔG), Naloxone (ZINC000000389747), Fenoldopam (ZINC000022116608), Labetalol (ZINC000000403010) and Thalitone (ZINC000000057255) were identified that showed high binding energies as -10.2, -10.1, -9.9 and -9.8 kcal/mol, respectively. In 2D analysis, these drugs also showed considerable structural conformer of hydrogen and hydrophobic interactions. Further, a 100 ns MD simulation study found the lowest deviation and fluctuations with various intermolecular interactions to stabilise the complexes. Out of 4, the Naloxone molecule showed robust, steady, and stable RMSD 0.23 ± 0.18 nm. Further, MMGBSA analysis supports MD results and found strong binding energy (ΔG) -29.71 ± 4.97 kcal/mol. In Comparative studies with Neu5Ac2en (native substrate) revealed naloxone has a higher affinity for sialidase. The PCA analysis showed that Naloxone and Thalitone were actively located on the active site, and other compounds were flickered. Our extensive computational and statistical report demonstrates that these FDA drugs can be validated as potential sialidase inhibitors.Communicated by Ramaswamy H. Sarma.

Overdose responses among rural people who use drugs: A multi-regional qualitative study

BACKGROUND

Efforts to distribute naloxone have equipped more people with the ability to reverse opioid overdoses but people who use drugs are often reluctant to call 911 due to concerns for legal repercussions. Rural communities face unique challenges in reducing overdose deaths compared to urban communities, including limited access to harm reduction services as well as greater concerns about stigma and privacy.

METHODS

The Rural Opioid Initiative was funded in 2017 to better understand the health-related harms associated with the opioid crisis in rural US communities and consists of eight studies spanning ten states and 65 counties. Each study conducted semi-structured qualitative interviews with people who use drugs to understand contextual factors influencing drug use and health behaviors. We analyzed qualitative data from seven studies with data available at the time of analysis to understand peer response to overdose.

RESULTS

Of the 304 participants interviewed, 55% were men, 70% were white, 80% reported current injection drug use, and 60% reported methamphetamine use. Similar to what has been found in studies focused on urban settings, people who use drugs in rural communities use a range of strategies to reverse overdoses, including non-evidence-based approaches. Several reported that multiple doses of naloxone are needed to reverse overdose. Three themes emerged around the willingness to call 911, including (1) hesitancy to call 911 for fear of legal consequences, (2) negative perceptions or experiences with law enforcement officers, and (3) efforts to obtain medical intervention while avoiding identification/law enforcement involvement.

CONCLUSION

People who use drugs employ multiple strategies to attempt overdose reversal, including non-evidence-based approaches. Greater education about the most effective and least harmful strategies is needed. Reluctance to call 911 is rooted in concerns about potential legal consequences as well as perceptions about law enforcement officers, which may be heightened in rural communities where people who use drugs are more easily identified by law enforcement. People who use drugs will go to great strides to connect their peers to needed medical services, suggesting that comprehensive interventions to reduce interactions with law enforcement officers and eliminate legal consequences for reporting overdoses are critical.

High-dose naloxone formulations are not as essential as we thought

Naloxone is an effective FDA-approved opioid antagonist for reversing opioid overdoses. Naloxone is available to the public and can be administered through intramuscular (IM), intravenous (IV), and intranasal spray (IN) routes. Our literature review investigates the adequacy of two doses of standard IM or IN naloxone in reversing fentanyl overdoses compared to newer high-dose naloxone formulations. Moreover, our initiative incorporates the experiences of people who use drugs, enabling a more practical and contextually-grounded analysis. The evidence indicates that the vast majority of fentanyl overdoses can be successfully reversed using two standard IM or IN dosages. Exceptions include cases of carfentanil overdose, which necessitates ≥ 3 doses for reversal. Multiple studies documented the risk of precipitated withdrawal using ≥ 2 doses of naloxone, notably including the possibility of recurring overdose symptoms after resuscitation, contingent upon the half-life of the specific opioid involved. We recommend distributing multiple doses of standard IM or IN naloxone to bystanders and educating individuals on the adequacy of two doses in reversing fentanyl overdoses. Individuals should continue administration until the recipient is revived, ensuring appropriate intervals between each dose along with rescue breaths, and calling emergency medical services if the individual is unresponsive after two doses. We do not recommend high-dose naloxone formulations as a substitute for four doses of IM or IN naloxone due to the higher cost, risk of precipitated withdrawal, and limited evidence compared to standard doses. Future research must take into consideration lived and living experience, scientific evidence, conflicts of interest, and the bodily autonomy of people who use drugs.

Total-body imaging of mu-opioid receptors with [11C]carfentanil in non-human primates

PURPOSE

Mu-opioid receptors (MORs) are widely expressed in the central nervous system (CNS), peripheral organs, and immune system. This study measured the whole body distribution of MORs in rhesus macaques using the MOR selective radioligand [11C]carfentanil ([11C]CFN) on the PennPET Explorer. Both baseline and blocking studies were conducted using either naloxone or GSK1521498 to measure the effect of the antagonists on MOR binding in both CNS and peripheral organs.

METHODS

The PennPET Explorer was used for MOR total-body PET imaging in four rhesus macaques using [11C]CFN under baseline, naloxone pretreatment, and naloxone or GSK1521498 displacement conditions. Logan distribution volume ratio (DVR) was calculated by using a reference model to quantitate brain regions, and the standard uptake value ratios (SUVRs) were calculated for peripheral organs. The percent receptor occupancy (%RO) was calculated to establish the blocking effect of 0.14 mg/kg naloxone or GSK1521498.

RESULTS

The %RO in MOR-abundant brain regions was 75-90% for naloxone and 72-84% for GSK1521498 in blocking studies. A higher than 90% of %RO were observed in cervical spinal cord for both naloxone and GSK1521498. It took approximately 4-6 min for naloxone or GSK1521498 to distribute to CNS and displace [11C]CFN from the MOR. A smaller effect was observed in heart wall in the naloxone and GSK1521498 blocking studies.

CONCLUSION

[11C]CFN total-body PET scans could be a useful approach for studying mechanism of action of MOR drugs used in the treatment of acute and chronic opioid use disorder and their effect on the biodistribution of synthetic opioids such as CFN. GSK1521498 could be a potential naloxone alternative to reverse opioid overdose.

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.

Acute opioid overdose in pediatric patients

Recent increases in pediatric and adolescent opioid fatalities mandate an urgent need for early consideration of possible opioid exposure and specific diagnostic and management strategies and interventions tailored to these unique populations. In contrast to adults, pediatric methods of exposure include accidental ingestions, prescription misuse, and household exposure. Early recognition, appropriate diagnostic evaluation, along with specialized treatment for opioid toxicity in this demographic are discussed. A key focus is on Naloxone, an essential medication for opioid intoxication, addressing its unique challenges in pediatric use. Unique pediatric considerations include recognition of accidental ingestions in our youngest population, critical social aspects including home safety and intentional exposure, and harm reduction strategies, mainly through Naloxone distribution and education on safe medication practices. It calls for a multifaceted approach, including creating pediatric-specific guidelines, to combat the opioid crisis among children and to work to lower morbidity and mortality from opioid overdoses.

Are carfentanil and acrylfentanyl naloxone resistant?

The rapid rise in deaths since 2012 due to opioid poisoning is correlated with the proliferation of potent synthetic opioid agonists such as fentanyl, acrylfentanyl, and carfentanil. The efficacy of frontline antidotes such as naloxone in reversing such poisoning events has been questioned, and the possibility of naloxone-resistant synthetic opioids has been raised. In this manuscript, we applied in vitro techniques to establish the median effective inhibitory concentrations for fentanyl, acrylfentanyl, and carfentanil and subsequently evaluate naloxone's ability to reverse agonist-receptor interactions.

Intranasal Naloxone for Opioid Overdose

This JAMA Insights describes indications for naloxone use in preventing opioid overdoses and benefits vs barriers to its availability following FDA approval of its availability without a prescription.

Trends and correlates of naloxone possession and use among people who inject drugs in Seattle, Washington

BACKGROUND

Naloxone distribution has been implemented as an essential opioid overdose prevention measure for people who inject drugs (PWID), and many jurisdictions in the United States have implemented policy change to increase naloxone access. This project describes temporal trends in and correlates of naloxone possession and use among PWID in the Seattle area of Washington State.

METHODS

Using a repeat cross-sectional design, we utilized two sets of serial cross-sectional surveys of PWID, which included biennial surveys of Seattle area syringe service program (SSP) clients and community-based National HIV Behavioral Surveillance surveys of PWID (NHBS-PWID) conducted from 2012-2019. Survey participant characteristics were descriptively compared between participants reporting naloxone possession to those not reporting naloxone possession. Multivariable Poisson regression was used to calculate prevalence ratios for naloxone possession comparing later to earlier survey years, adjusting for age, gender, race/ethnicity, primary drug, and experiencing and witnessing an overdose in the past 12 months.

RESULTS

Naloxone possession and use increased in both survey populations. The prevalence of possessing naloxone was 2.8 times greater [2019 vs. 2013= 95% CI: 2.40-3.33] among SSP participants and 2.8 times greater [2018 vs. 2012=95% CI: 2.41-3.16] among NHBS-PWID participants for the most recent time period. The prevalence of naloxone use was 1.3 times greater [2019 vs. 2017= 95% CI: 1.13-1.58] and 2.1 times greater [2015 vs. 2012=95% CI:1.62-2.73] among SSP and NHBS-PWID participants, respectively, for the most recent time period.

CONCLUSION

Naloxone possession and use increased in PWID in the Seattle area from 2012-2019, and is, at least in part, likely the result of numerous policy and programmatic efforts to facilitate easier naloxone accessibility in the wake of dramatic increases in overdose mortality. Further research on disparities in naloxone possession are needed to ensure equitable access.

2023 American Heart Association Focused Update on the Management of Patients With Cardiac Arrest or Life-Threatening Toxicity Due to Poisoning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

In this focused update, the American Heart Association provides updated guidance for resuscitation of patients with cardiac arrest, respiratory arrest, and refractory shock due to poisoning. Based on structured evidence reviews, guidelines are provided for the treatment of critical poisoning from benzodiazepines, β-adrenergic receptor antagonists (also known as β-blockers), L-type calcium channel antagonists (commonly called calcium channel blockers), cocaine, cyanide, digoxin and related cardiac glycosides, local anesthetics, methemoglobinemia, opioids, organophosphates and carbamates, sodium channel antagonists (also called sodium channel blockers), and sympathomimetics. Recommendations are also provided for the use of venoarterial extracorporeal membrane oxygenation. These guidelines discuss the role of atropine, benzodiazepines, calcium, digoxin-specific immune antibody fragments, electrical pacing, flumazenil, glucagon, hemodialysis, hydroxocobalamin, hyperbaric oxygen, insulin, intravenous lipid emulsion, lidocaine, methylene blue, naloxone, pralidoxime, sodium bicarbonate, sodium nitrite, sodium thiosulfate, vasodilators, and vasopressors for the management of specific critical poisonings.

Agomir-331 Suppresses Reactive Gliosis and Neuroinflammation after Traumatic Brain Injury

Traumatic brain injury usually triggers glial scar formation, neuroinflammation, and neurodegeneration. However, the molecular mechanisms underlying these pathological features are largely unknown. Using a mouse model of hippocampal stab injury (HSI), we observed that miR-331, a brain-enriched microRNA, was significantly downregulated in the early stage (0-7 days) of HSI. Intranasal administration of agomir-331, an upgraded product of miR-331 mimics, suppressed reactive gliosis and neuronal apoptosis and improved cognitive function in HSI mice. Finally, we identified IL-1β as a direct downstream target of miR-331, and agomir-331 treatment significantly reduced IL-1β levels in the hippocampus after acute injury. Our findings highlight, for the first time, agomir-331 as a pivotal neuroprotective agent for early rehabilitation of HSI.

High-Dose Naloxone Formulations Are Not as Essential as We Thought

Naloxone is a U.S. Food and Drug Administration (FDA) approved opioid antagonist for reversing opioid overdoses. Naloxone is available to the public, and can be administered through intramuscular (IM), intravenous (IV), and intranasal spray (IN) routes. Our literature review aimed to improve understanding regarding the adequacy of the regularly distributed two doses of low-dose IM or IN naloxone in effectively reversing fentanyl overdoses and whether high-dose naloxone formulations (HDNF) formulations are an optimal solution to this problem. Moreover, our initiative incorporated the perspectives and experiences of people who use drugs (PWUD), enabling a more practical and contextually-grounded analysis. We began by discussing the knowledge and perspectives of Tennessee Harm Reduction, a small peer-led harm reduction organization. A comprehensive literature review was then conducted to gather relevant scholarly works on the subject matter. The evidence indicates that, although higher doses of naloxone have been administered in both clinical and community settings, the vast majority of fentanyl overdoses can be successfully reversed using standard IM dosages with the exception of carfentanil overdoses and other more potent fentanyl analogs, which necessitate three or more doses for effective reversal. Multiple studies documented the risk of precipitated withdrawal using high doses of naloxone. Notably, the possibility of recurring overdose symptoms after resuscitation exists, contingent upon the half-life of the specific opioid. Considering these findings and the current community practice of distributing multiple doses, we recommend providing at least four standard doses of IN or IM naloxone to each potential bystander, and training them to continue administration until the recipient achieves stability, ensuring appropriate intervals between each dose. Based on the evidence, we do not recommend HDNF in the place of providing four doses of standard naloxone due to the higher cost, risk of precipitated withdrawal and limited evidence compared to standard IN and IM. All results must be taken into consideration with the inclusion of the lived experiences, individual requirements, and consent of PWUD as crucial factors. It is imperative to refrain from formulating decisions concerning PWUD in their absence, as their participation and voices should be integral to the decision-making process.

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.

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.

Identification and Treatment of Opioid-Associated Out-of-Hospital Cardiac Arrest in Emergency Medical Service Protocols

This cross-sectional study reviews emergency medical services (EMS) treatment protocols for adults presenting with cardiac arrest or overdose to evaluate whether current protocols include the consideration of opioid overdose for patients with possible out-of-hospital cardiac arrest.

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.

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.

Closed-loop wearable naloxone injector system

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

Impact of the Opioid Epidemic

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

Endogenous opiates and behavior: 2019

This paper is the forty-second consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2019 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).

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.

Availability of Naloxone in 2 Underserved Urban Communities in Georgia

In 2016, unintentional injuries became the third leading cause of death in the United States. In 2018, 54% of 103 672 unintentional injury deaths were due to drug overdoses among adults 19 to 64 years of age. In Georgia, opioid overdose deaths continued to increase, despite a 2014 state law for naloxone use to prevent deaths, and a 2017 amendment for more widespread community use without a prescription. Given these policies, naloxone availability in pharmacies in underserved communities remains unclear. Our objective is to explore naloxone availability in such communities. Three Public Health and Preventive Medicine residents during a social-cultural-behavioral longitudinal rotation conducted interviews of 9 community pharmacists. Several themes emerged: more education was needed, and naloxone was available only by prescription in certain pharmacies or in limited amounts. Additional assessments among community members and sectors can examine the extent to which policies to expand naloxone availability and accessibility are implemented, including reduced naloxone costs.

Systematic review of the emerging literature on the effectiveness of naloxone access laws in the United States

BACKGROUND AND AIMS

Naloxone access laws (NALs) have been suggested to be an important strategy to reduce opioid-related harm. We describe the evolution of NALs across states and over time and review existing evidence of their overall association with naloxone distribution and opioid overdose as well as the potential effects of specific NAL components.

METHODS

Descriptive analysis of temporal variation in US regional adoption of NAL components, accompanied by a systematic search of 13 databases for studies (published between 2005 and 20 December 2019) assessing the effects of NALs on naloxone distribution or opioid-related health outcomes. Eleven studies, all published since 2018, met inclusion criteria. Study time-frames spanned 1999-2017. Opioid-related overdose mortality, emergency department episodes and naloxone distribution were correlated with the presence of a NAL and, where data were available, NAL components.

RESULTS

Existing evidence suggests mixed, but generally beneficial, effects for NALs. Nearly all studies show that NALs, particularly those that permit naloxone distribution without patient-specific prescriptions, are associated with increased naloxone access [incidence rate ratios (IRR) range from 1.40, 95% confidence interval (CI) = 1.15-1.66 to 7.75, 95% CI = 1.22-49.35] and increased opioid-related emergency department visits (IRR range from 1.14, 95% CI = 1.07-1.20 to 1.15, 95% CI = 1.02-1.29). Most studies show NALs are associated with reduced overdose mortality, although findings vary depending on the specific NAL components and time-period analyzed (IRR range from 0.66, 95% CI = 0.42-0.90 to 1.27, 95% CI = 1.27-1.27). Few studies account for the variation in opioid environments (i.e. illicit versus prescription) or other policy dimensions that may be correlated with outcomes.

CONCLUSIONS

The existing literature on naloxone access laws in the United States supports beneficial effects for increased naloxone distribution, but provides inconclusive evidence for reduced fatal opioid overdose. Mixed findings may reflect variation in the laws' design and implementation, confounding effects of concurrent policy adoption, or differential effectiveness in light of changing opioid environments.

Naloxone Use by Emergency Medical Services During the COVID-19 Pandemic: A National Survey

OBJECTIVES

The COVID-19 epidemic in the United States has hit in the midst of the opioid overdose crisis. Emergency medical services (EMS) clinicians may limit their use of intranasal naloxone due to concerns of novel coronavirus infection. We sought to determine changes in overdose events and naloxone administration practices by EMS clinicians.

METHODS

Between April 29, 2020 and May 15, 2020, we surveyed directors of EMS fellowship programs across the US about how overdose events and naloxone administration practices had changed in their catchment areas since March 2020.

RESULTS

Based on 60 respondents across all regions of the country, one fifth of surveyed communities have experienced an increase in opioid overdoses and events during which naloxone was administered, and 40% have experienced a decrease. The findings varied by region of the country. Eighteen percent of respondents have discouraged or prohibited the use of intranasal naloxone with 10% encouraging the use of intramuscular naloxone.

CONCLUSIONS

These findings may provide insight into changes in opioid overdose mortality during this time and assist in future disaster planning.

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).

Intranasal versus intramuscular naloxone for opioid overdose

Review of: Dietze P, Jauncey M, Salmon A. Effect of intranasal vs intramuscular naloxone on opioid overdose: a randomised clinical trial. JAMA Network Open 2019;2:e1914977.

Intranasal epinephrine effects on epinephrine pharmacokinetics and heart rate in a nasal congestion canine model

BACKGROUND

Histamine release and vasodilation during an allergic reaction can alter the pharmacokinetics of drugs administered via the intranasal (IN) route. The current study evaluated the effects of histamine-induced nasal congestion on epinephrine pharmacokinetics and heart rate changes after IN epinephrine.

METHODS

Dogs received 5% histamine or saline IN followed by 4 mg epinephrine IN. Nasal restriction pressure, epinephrine concentration, and heart rate were assessed. Maximum concentration (Cmax), area under plasma concentration-time curve from 1 to 90 min (AUC1-90), and time to reach Cmax (Tmax) were measured. Clinical observations were documented.

RESULTS

In the 12 dogs in this study, nasal congestion occurred at 5-10 min after IN histamine administration versus no nasal congestion after IN saline. After administration of IN epinephrine, IN histamine-mediated nasal congestion was significantly reduced to baseline levels at 60, 80, and 100 min. There were no significant differences in Cmax and AUC1-90 between histamine and saline groups after IN epinephrine delivery (3.5 vs 1.7 ng/mL, p = 0.06, and 117 vs 59 ng/mL*minutes, p = 0.09, respectively). After receiving IN epinephrine, the histamine group had a significantly lower Tmax versus the saline group (6 vs 70 min, respectively; p = 0.02). Following IN epinephrine administration, the histamine group showed rapidly increased heart rate at 5 min, while there was a delayed increase in heart rate (occurring 30-60 min after administration) in the saline group. Clinical observations included salivation and emesis.

CONCLUSION

IN histamine led to more rapid epinephrine absorption and immediately increased heart rate compared with IN saline. IN epinephrine decreased histamine-induced nasal congestion.