Authors' objectives: Opioids kill more people than any other drug. Naloxone is an opioid antagonist which can be distributed in take-home ‘kits’ for peer administration (take-home naloxone). Opioids, such as heroin, kill more people worldwide by overdose than any other type of drug, and death rates associated with opioid poisoning in the United Kingdom (UK) are at record levels. Naloxone is an opioid antagonist which can be distributed in ‘kits’ for administration by witnesses in an overdose emergency. This intervention is known as take-home naloxone (THN). We know that THN can save lives on an individual level, but there is currently limited evidence about the effectiveness of THN distribution on an aggregate level, in specialist drug service settings or in emergency service (ES) settings. Notably, we do not know whether THN kits reduce deaths from opioid overdose in at-risk populations, if there are unforeseen harms associated with THN distribution or if THN is cost-effective. To address this research gap, we aimed to determine the feasibility of a fully powered cluster randomised controlled trial (RCT) of THN distribution in emergency settings. To determine: the best form of THN kit, training and delivery whether a trial clustered by emergency department (ED) catchment area and the associated ambulance service (AS) is deliverable, as assessed against predefined progression criteria related to intervention, trial design and methods.

Authors' results and conclusions: This study did not meet progression criteria for intervention or trial methods feasibility, so outcomes were not followed up and a fully powered trial is not planned. This study found that it was not feasible to deliver or evaluate this form of take-home naloxone, using this study design, in emergency care. TABLE S1Assessment against preset progression criteria Criteria Achieved Criteria met Sign-up of four sites, including ≥ 50% eligible staff to complete training in delivering the intervention at each intervention site Site 1: ED trained 81.1%, AS trained 54% of eligible staffSite 2: ED trained 8.1%, AS trained 33.8% of eligible staff No Identification of ≥ 75% of people who have presented to ED or AS with opioid overdose or an opioid use-related problem over a 12-month period Unable to assess Not known THN kits issued to ≥ 50% eligible patients over a 12-month period at intervention sites 21.7% of eligible patients were given kits No Serious adverse event rate (to be defined in agreement with the DMEC) of no more than 10% difference in intervention sites to control sites at the conclusion of recruitment No serious adverse events were reported Yes Identification and inclusion for follow-up of ≥ 75% of people who died of opioid poisoning in the following year in the study areas according to ONS mortality data (previous ONS data suggest between 140 and 180 such deaths across the four participating sites during the study period) We were able to identify decedents from opioid poisoning in Wales but were unable to produce a discriminant function which included this group in a sufficiently small section of the general population, or to test these methods in a second population No Matching and data linkage in ≥ 90% of cases not dissented at the conclusion of quantitative data collection Due to significant delays in permissions processes for routine- linked data retrieval from NHS Digital, and low administration of THN kits, we did not attempt to match and link records for patients recruited to the trial No Retrieval of routinely recorded primary and secondary outcomes from national repositories within six-months of projected timeline Again, due to significant delays in permissions processes for routine- linked data retrieval, and low administration of THN kits, we did not attempt to retrieve routinely recorded primary and secondary outcomes No Discriminant function With low numbers of opioid-related deaths (1105/3,227,396) and a high proportion of them having no contact with health services in the year before death, the predictive link between death and opioid-related healthcare events was weak. Logistic regression models indicated we would need to monitor one-third of the population to capture 75% of the decedents from opioid overdose in 1-year follow-up. This study did not meet progression criteria for intervention or trial methods feasibility, so outcomes were not followed up and a fully powered trial is not planned. There does appear to be appetite for THN kit provision and training in the emergency setting. We conclude that the THN intervention as defined and administered in the Take-home naloxone Intervention Multicentre Emergency setting (TIME) study was not feasible and should not therefore go forward to full trial. However, there may be space for further development of this complex intervention in emergency care – for example, for protocols to allow administration to family and friends of opioid users; as well as methods for definition and identification of study cohorts for outcome comparisons.

Authors' methods: We used Welsh routine data (2015–21) to test the feasibility of developing a discriminant function to identify people at high risk of fatal opioid overdose. We carried out a cluster randomised controlled trial and qualitative study to examine experiences of service users and providers. We assessed feasibility of intervention and trial methods against predetermined progression criteria related to: site sign-up, staff trained, identification of eligible patients, proportion given kits, identification of people who died of opioid poisoning, data linkage and retrieval of outcomes. This study was carried out in the emergency environment; sites comprised an emergency department and associated ambulance service catchment area. At intervention sites, we invited emergency department clinicians and paramedics to participate. We recruited adult patients who arrived at the emergency department or were attended to by ambulance paramedics for a problem related to opioid use with capacity to consent to receiving the take-home naloxone and related training. Usual care comprised basic life support plus naloxone by paramedics or emergency department staff. The take-home naloxone intervention was offered in addition to usual care, with guidance for recipients on basic life support, the importance of calling the emergency services, duration of effect, safety and legality of naloxone administration. The Take-home naloxone Intervention Multicentre Emergency setting study was interrupted by coronavirus disease. We assessed feasibility of intervention and trial methods based upon the following predetermined progression criteria. Intervention feasibility Sign-up of four sites, including ≥ 50% eligible staff to complete training in delivering the intervention at each intervention site. Identification of ≥ 75% of people who have presented to ED or AS with opioid overdose or an opioid use-related problem over a 12-month period. THN kits issued to ≥ 50% eligible patients over a 12-month period at intervention sites. Serious adverse event rate [to be defined in agreement with Data Monitoring and Ethics Committee (DMEC)] of no more than 10% difference in intervention sites to control sites at the conclusion of recruitment. This feasibility study was carried out in the emergency care environment, across study sites each centred on a receiving ED and defined geographically as the local AS catchment area for that receiving ED. At intervention sites, we invited ED clinicians and paramedics to participate in the trial and recruited adult patients who arrived at the ED or were attended by ambulance paramedics for a problem related to opioid use with capacity to consent to receiving the THN and related training. Participants were to be identified for outcome comparison by application of the discriminant function, if completed, to the study site general populations. Usual care comprised administration of basic life support plus naloxone by paramedics or ED staff. The THN intervention was offered in addition to usual care and included a multi dose THN kit (Prenoxad) containing 2 mg naloxone hydrochloride 1 mg/1 ml solution for intramuscular (IM) injection, and instructions on the correct administration of the naloxone dose. Recipients also received guidance on: BLS; the importance of calling the ES; duration of effect; the safety of naloxone in terms of adverse events and overdose; and the legality of bystander administration of naloxone.

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hta/16/91/04

Year Published: 2024

URL for published report: https://www.journalslibrary.nihr.ac.uk/hta/YNRC8249

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: England, United Kingdom

DOI: 10.3310/YNRC8249

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk