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

What is the Evidence for Using Intranasal Medicine in the Prehospital Setting? A Systematic Review

OBJECTIVES

Intranasal (IN) medications offer a safe non-invasive way to rapidly deliver drugs in situations where intravenous (IV) access and intramuscular (IM) administration is challenging or not feasible. In the prehospital setting, this can be an essential alternative in time critical situations including trauma management, seizures, and agitated patients. However, there is a paucity of evidence summarizing its efficacy in this environment. This systematic review aims to assess the current evidence supporting the use of IN medicine (midazolam, ketamine, fentanyl, morphine, glucagon, and naloxone) in the prehospital setting alone.

METHODS

A systematic literature search (PROSPERO CRD42023440713) of PubMed, Web of Science, OVID Medline, "Cochrane Central Register of Controlled Trials," Cochrane reviews and Embase was performed from inception to June 2023 to identify studies where IN medications were administered to patients in the prehospital setting. All randomized controlled trials, observational cohort studies, case series, and case reports were included. Papers not written in English, review articles, abstracts, and non-published data (including letters to the editor) were excluded. The methodological quality of the included studies was interpreted using the Cochrane risk of bias tool and rated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. No funding was received.

RESULTS

From 4818 studies, 39 were included (seven for midazolam, five for ketamine, twelve for fentanyl, one for diamorphine, two for glucagon, and twelve for naloxone). A total of 24,097 patients were treated with IN medications across all the studies. There were five moderate quality, four low quality, and thirty very low quality studies. The potential efficacy of IN fentanyl and ketamine was demonstrated consistently throughout the studies with less clear evidence for midazolam, morphine, glucagon, and naloxone. This review was severely limited by the study quality, with most studies demonstrating "high concerns" for bias.

CONCLUSIONS

Prehospital IN medication administration has wide-ranging potential, particularly for administering analgesia. There are likely to be certain populations, for example, pediatrics, that will benefit the most, although conclusions are limited by the quality of evidence currently available. We encourage additional research in this area, particularly with robust prospective double-blind RCTs.

Naloxone use by Aotearoa New Zealand emergency medical services, 2017-2021

OBJECTIVE

Emergency medical services (EMS) use of naloxone in the prehospital setting is indicated in patients who have significantly impaired breathing or level of consciousness when opioid intoxication is suspected. The present study characterised naloxone use in a nationwide sample of Aotearoa New Zealand road EMS patients to establish a baseline for surveillance of any changes in the future.

METHODS

A retrospective analysis of rates of patients with naloxone administrations was conducted using Hato Hone St John (2017-2021) and Wellington Free Ambulance (2018-2021) electronic patient report form datasets. Patient demographics, presenting complaints, naloxone dosing, and initial and last vital sign clinical observations were described.

RESULTS

There were 2018 patients with an equal proportion of males and females, and patient median age was 47 years. There were between 8.0 (in 2018) and 9.0 (in 2020) naloxone administrations per 100 000 population-years, or approximately one administration per day for the whole country of 5 million people. Poisoning by unknown agent(s) was the most common presenting complaint (61%). The median dose of naloxone per patient was 0.4 mg; 85% was administered intravenously. The median observed change in Glasgow Coma Scale score was +1, and respiratory rate increased by +2 breaths/min.

CONCLUSIONS

A national rate of EMS naloxone patients was established; measured clinical effects of naloxone were modest, suggesting many patients had reasons other than opioid toxicity contributing to their symptoms. Naloxone administration rates provide indirect surveillance information about suspected harmful opioid exposures but need to be interpreted with care.

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.

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.

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.

Intranasal analgesia for acute moderate to severe pain in children - a systematic review and meta-analysis

BACKGROUND

Children in acute pain often receive inadequate pain relief, partly from difficulties administering injectable analgesics. A rapid-acting, intranasal (IN) analgesic may be an alternative to other parenteral routes of administration. Our review compares the efficacy, safety, and acceptability of intranasal analgesia to intravenous (IV) and intramuscular (IM) administration; and to compare different intranasal agents.

METHODS

We searched Cochrane Library, MEDLINE/PubMed, Embase, Web of Knowledge, Clinicaltrials.gov, Controlled-trials.com/mrcr, Clinicaltrialsregister.eu, Apps.who.int/trialsearch. We also screened reference lists of included trials and relevant systematic reviews. Studies in English from any year were included. Two authors independently assessed all studies. We included randomised trials (RCTs) of children 0-16, with moderate to severe pain; comparing intranasal analgesia to intravenous or intramuscular analgesia, or to other intranasal agents. We excluded studies of procedural sedation or analgesia. We extracted study characteristics and outcome data and assessed risk of bias with the ROB 2.0-tool. We conducted meta-analysis and narrative review, evaluating the certainty of evidence using GRADE. Outcomes included pain reduction, adverse events, acceptability, rescue medication, ease of and time to administration.

RESULTS

We included 12 RCTs with a total of 1163 children aged 3 to 20, most below 10 years old, with a variety of conditions. Our review shows that: - There may be little or no difference in pain relief (single dose IN vs IV fentanyl MD 4 mm, 95% CI -8 to 16 at 30 min by 100 mm VAS; multiple doses IN vs IV fentanyl MD 0, 95%CI -0.35 to 0.35 at 15 min by Hannallah score; single dose IN vs IV ketorolac MD 0.8, 95% CI -0.4 to 1.9 by Faces Pain Scale-Revised), adverse events (single dose IN vs IV fentanyl RR 3.09, 95% CI 0.34 to 28.28; multiple doses IN vs IV fentanyl RR 1.50, 95%CI 0.29 to 7.81); single dose IN vs IV ketorolac RR 0.716, 95% CI 0.23 to 2.26), or acceptability (single dose IN vs IV ketorolac RR 0.83, 95% CI 0.66 to 1.04) between intranasal and intravenous analgesia (low certainty evidence). - Intranasal diamorphine or fentanyl probably give similar pain relief to intramuscular morphine (narrative review), and are probably more acceptable (RR 1.60, 95% CI 1.42 to 1.81) and tolerated better (RR 0.061, 95% CI 0.03 to 0.13 for uncooperative/negative reaction) (moderate certainty); adverse events may be similar (narrative review) (low certainty). - Intranasal ketamine gives similar pain relief to intranasal fentanyl (SMD 0.05, 95% CI -0.20 to 0.29 at 30 min), while having a higher risk of light sedation (RR 1.74, 95% CI 1.30 to 2.35) and mild side effects (RR 2.16, 95% CI 1.72 to 2.71) (high certainty). Need for rescue analgesia is probably similar (RR 0.85, 95% CI 0.62 to 1.17) (moderate certainty), and acceptability may be similar (RR 1.15, 95% CI 0.89 to 1.48) (low certainty).

CONCLUSIONS

Our review suggests that intranasal analgesics are probably a good alternative to intramuscular analgesics in children with acute moderate to severe pain; and may be an alternative to intravenous administration. Intranasal ketamine gives similar pain relief to fentanyl, but causes more sedation, which should inform the choice of intranasal agent.