Potential uses of naltrexone in emergency department patients with opioid use disorder.

Introduction: Despite widespread recognition of the opioid crisis, opioid overdose remains a common reason for Emergency Department (ED) utilization. Treatment for these patients after stabilization often involves the provision of information for outpatient treatment options. Ideally, an ED visit for overdose would present an opportunity to start treatment for opioid use disorder (OUD) immediately. Although widely recognized as effective, opioid agonist therapy with methadone and buprenorphine commonly referred to as "medication-assisted therapy" but more correctly as "medication for addiction treatment" (MAT), can be difficult to access even for motivated individuals due to shortages of prescribers and treatment programs. Moreover, opioid agonist therapy may not be appropriate for all patients, as many patients who present after overdose are not opioid dependent. More treatment options are required to successfully match patients with diverse needs to an optimal treatment plan in order to avoid relapse. Naltrexone, a long-acting opioid antagonist, available orally and as a monthly extended-release intramuscular injection, may represent another treatment option. Methods: We conducted a literature search of MEDLINE and PubMed. We aimed to capture references related to naltrexone and is use as MAT for OUD, as well as manuscripts that discussed naltrexone in comparison toother agents used for MAT, opioid detoxification, and naltrexone metabolism. Our initial search logic returned a total of 618 articles. Following individual evaluation for relevance, we selected 65 for in-depthreview. Manuscripts meeting criteria were examined for citations meriting further review, leading to the addition of 30 manuscripts Conclusions: Here, we review the pharmacology of naltrexone as it relates to OUD, its history of use, and highlight recent studies and new approaches for use of the drug as MAT including its potential initiation after ED visit for opioid overdose.