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.