Potential pathophysiological role of the ion channel TRPM3 in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and the therapeutic effect of low-dose naltrexone.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating disease with a broad overlap of symptomatology with Post-COVID Syndrome (PCS). Despite the severity of symptoms and various neurological, cardiovascular, microvascular, and skeletal muscular findings, no biomarkers have been identified. The Transient receptor potential melastatin 3 (TRPM3) channel, involved in pain transduction, thermosensation, transmitter and neuropeptide release, mechanoregulation, vasorelaxation, and immune defense, shows altered function in ME/CFS. Dysfunction of TRPM3 in natural killer (NK) cells, characterized by reduced calcium flux, has been observed in ME/CFS and PCS patients, suggesting a role in ineffective pathogen clearance and potential virus persistence and autoimmunity development. TRPM3 dysfunction in NK cells can be improved by naltrexone in vitro and ex vivo, which may explain the moderate clinical efficacy of low-dose naltrexone (LDN) treatment. We propose that TRPM3 dysfunction may have a broader involvement in ME/CFS pathophysiology, affecting other organs. This paper discusses TRPM3's expression in various organs and its potential impact on ME/CFS symptoms, with a focus on small nerve fibers and the brain, where TRPM3 is involved in presynaptic GABA release.

Pregnancy Rates Among Women Treated with Medication for Opioid Use Disorder.

BACKGROUND: Treatment-seeking people with opioid use disorder (OUD) who are capable of pregnancy need accurate information about the potential impact of medication to treat OUD (MOUD) on fertility to make informed choices about treatment that are consistent with their reproductive wishes. There is a dearth of research on fertility associated with MOUD receipt in birthing people with OUD. OBJECTIVE: To estimate the association between treatment with MOUD and odds of conception among birthing people using national administrative claims. DESIGN: Retrospective case-crossover study using multi-state US administrative data (2006-2016). Dates of conception were estimated from delivery dates and served as "case" days for which MOUD exposures were compared to those on all other ("control") days of insurance enrollment. PARTICIPANTS: Treatment-seeking people with OUD with a delivery during the observation period. MAIN MEASURES: Odds ratios for conception from within-person fixed effects models were modeled as a function of exposure to MOUD (buprenorphine, methadone, extended-release depot naltrexone, or oral naltrexone) using conditional logistic regression. KEY RESULTS: A total of 21,928 births among 19,133 people with OUD were identified. In the sample, 5873 people received buprenorphine, 1825 methadone, 486 extended-release naltrexone, and 714 oral naltrexone. Participants could receive more than one type of MOUD. Mean age was 28.2 years (SD = 2.2; range = 16-45), with 76.2% having Medicaid. vs. commercial insurance. Compared to no MOUD, periods of methadone (aOR = 0.55 [95% CI = 0.48-0.63]) or buprenorphine receipt (aOR = 0.84 [0.77-0.91]) were associated with fewer conceptions. Treatment periods with extended-release depot naltrexone compared to no medication were associated with higher odds of conception (aOR = 1.75 [1.22-2.50]) and there was no significant difference in conception with oral naltrexone (aOR = 1.02 [0.67-1.54]). CONCLUSIONS: The association between MOUD and odds of conception among birthing people varied by type of MOUD, with extended-release naltrexone associated with higher odds of conceiving compared to no treatment. Clinical studies are urgently needed to investigate these findings further.

Perioperative Naltrexone Management: A Scoping Review by the Perioperative Pain and Addiction Interdisciplinary Network.

Substance use disorders, including alcohol use disorder, are a public health concern that affect more than 150 million people globally. The opioid antagonist naltrexone is being increasingly prescribed to treat opioid use disorder, alcohol use disorder, and chronic pain. Perioperative management of patients on naltrexone is inconsistent and remains a controversial topic, with mismanagement posing a significant risk to the long-term health of these patients. This scoping review was conducted to identify human studies in which the perioperative management of naltrexone was described. This review includes a systematic literature search involving Medline, Medline In-Process, Embase, PsycINFO, and Web of Science. Seventeen articles that describe perioperative naltrexone management strategies were included, including thirteen guidelines, one case report, and three randomized trials. Despite its use in patients with alcohol use disorder and chronic pain, no clinical studies, case reports, or guidelines addressed naltrexone use in these clinical populations. All of the guideline documents recommended the preoperative cessation of naltrexone, irrespective of dose, indication, or route of administration. None of these guideline documents were designed on the basis of a systematic literature search or a Delphi protocol. As described by the primary studies, perioperative pain relief varied depending on naltrexone dose and route of administration, time since last naltrexone administration, and underlying substance use disorder. None of the studies commented on the maintenance of recovery for the patient's substance use disorder in the context of perioperative naltrexone management. The current understanding of the risks and benefits of continuing or stopping naltrexone perioperatively is limited by a lack of high-quality evidence. In patients with risk factors for return to use of opioids or alcohol, the discontinuation of naltrexone should have a strong rationale. Future studies and guidelines should seek to address both acute pain management and maintaining recovery when discussing perioperative naltrexone management strategies.

Total and H-specific growth/differentiation factor 15 levels are unaffected by liraglutide or naltrexone/bupropion administration.

AIM: To investigate growth/differentiation factor 15 (GDF-15) levels in response to antiobesity medications, namely, liraglutide (Lira) and naltrexone/bupropion (N/B), in individuals with overweight or obesity. MATERIALS AND METHODS: This was a prospective, non-randomized clinical trial with a two-arm, parallel design. A total of 42 individuals with overweight or obesity without type 1 or type 2 diabetes mellitus were enrolled. The participants received either Lira 3 mg or N/B 32/360 mg, along with diet and exercise, according to comorbidities, cost and method of administration. Participants underwent clinical and laboratory measurements at baseline, as well as at the 3- and 6-month time points. Anthropometric measurements and body composition analysis via bioelectrical impendence analysis were performed. Total blood samples for GDF-15 and H-specific GDF-15 were collected in the fasting state and every 30 min for 3 h after the consumption of a standardized mixed meal. RESULTS: Overall, participants' weight was reduced by 9.29 ± 5.34 kg at Month 3 and 11.52 ± 7.52 kg at Month 6. Total and H-specific GDF-15 levels did not show significant changes during the mixed meal compared to values before the meal when all participants were examined at baseline, and at 3 and 6 month follow-ups. No statistical significance was found when participants were examined by subgroup (Lira vs. N/B). No significant differences between treatment groups in postprandial area under the curve (AUC) or incremental AUC values were found at baseline or in the follow-up months with regard to total and H-specific GDF-15 levels. CONCLUSION: Neither total nor H-specific GDF-15 levels are affected by Lira or N/B treatment in patients with overweight or obesity.

The safety and effectiveness of naldemedine for opioid-induced constipation in patients with advanced cancer in real-world palliative care settings: a multicenter prospective observational study.

PURPOSE: In this study, we aimed to evaluate the safety and effectiveness of naldemedine for treating opioid-induced constipation (OIC) in patients with advanced cancer, who are receiving palliative care, and particularly explored its early effects. METHODS: Palliative care teams and inpatient palliative care units across 14 institutions in Japan were included in this multicenter, prospective, observational study. Patients who were newly prescribed a daily oral dose of 0.2 mg naldemedine were enrolled. The spontaneous bowel movement (SBM) within 24 h after the first dose of naldemedine was considered the primary outcome, whereas, the secondary outcomes included weekly changes in SBM frequency and adverse events. RESULTS: A total of 204 patients were enrolled and 184 completed the 7-day study. The average age of the participants (103 males, 101 females) was 63 ± 14 years. The primary cancer was detected in the lungs (23.5%), gastrointestinal tract (13.7%), and urological organs (9.3%). A considerable proportion of patients (34.8%) had ECOG performance status of 3-4. Most patients were undergoing active cancer treatment, however, 40.7% of the patients were receiving the best supportive care. Within 24 h of the first naldemedine dose, 146 patients (71.6%, 95% CI: 65.4-77.8%) experienced SBMs. The weekly SBM counts increased in 62.7% of the participants. The major adverse events included diarrhea and abdominal pain, detected in 17.6% and 5.4% of the patients, respectively. However, no serious adverse events were observed. CONCLUSION: Conclusively, naldemedine is effective and safe for OIC treatments in real-world palliative care settings. TRIAL REGISTRATION NUMBER: UMIN000031381, registered 20/02/2018.

Optimizing Process Parameters for Controlled Drug Delivery: A Quality by Design (QbD) Approach in Naltrexone Microspheres.

The formulation of microspheres involves a complex manufacturing process with multiple steps. Identifying the appropriate process parameters to achieve the desired quality attributes poses a significant challenge. This study aims to optimize the critical process parameters (CPPs) involved in the preparation of naltrexone microspheres using a Quality by Design (QbD) methodology. Additionally, the research aims to assess the drug release profiles of these microspheres under both in vivo and in vitro conditions. Critical process parameters (CPPs) and critical quality attributes (CQAs) were identified, and a Box-Behnken design was utilized to delineate the design space, ensuring alignment with the desired Quality Target Product Profile (QTPP). The investigated CPPs comprised polymer concentration, aqueous phase ratio to organic phase ratio, and quench volume. The microspheres were fabricated using the oil-in-water emulsion solvent extraction technique. Analysis revealed that increased polymer concentration was correlated with decreased particle size, reduced quench volume resulted in decreased burst release, and a heightened aqueous phase ratio to organic phase ratio improved drug entrapment. Upon analyzing the results, an optimal formulation was determined. In conclusion, the study conducted in vivo drug release testing on both the commercially available innovator product and the optimized test product utilizing an animal model. The integration of in vitro dissolution data with in vivo assessments presents a holistic understanding of drug release dynamics. The QbD approach-based optimization of CPPs furnishes informed guidance for the development of generic pharmaceutical formulations.

Safer-use strategies in the context of harm-reduction treatment for people experiencing homelessness and alcohol use disorder.

BACKGROUND: Two, randomized controlled trials found harm-reduction treatment for AUD (HaRT-A) improves alcohol outcomes for adults experiencing homelessness. HaRT-A, which neither requires nor precludes abstinence, entails tracking alcohol-related harm, harm-reduction goals, and safer-use strategies. This secondary dual study qualitatively describes this last component, safer-use strategies, and their quantitative association with treatment outcomes. METHODS: Participants were people who experienced homelessness and AUD and were enrolled in the active HaRT-A treatment arms in 2 randomized control trials (Trial 1 N = 86; Trial 2 N = 208). Trial 1was a 2-arm study with randomization to HaRT-A or services as usual. Trial 2 was a 4-arm study combining HaRT-A and extended release naltrexone. In HaRT-A sessions, participants received a list of 3 categories of safer-use strategies (i.e., buffering alcohol's effects on the body, changing the manner of drinking to be safer and healthier, and reducing alcohol use). Mixed methods were used to qualitatively describe safer-use strategies implemented and quantitatively test their association with alcohol outcomes (i.e., peak quantity, frequency, alcohol-related harm). RESULTS: In Trial 1, but not Trial 2, participants committed to more safer-use strategies across time, which was associated with reductions in alcohol frequency over the past 30 days. In both trials, participants committing to reducing alcohol consumption drank on a quarter fewer days overall, and in Trial 2, experienced 15 % less alcohol-related harm. In Trial 1, participants who committed to changing the manner of drinking were heavier drinkers overall, and although they showed significant reductions in alcohol-related harm, their reduction rate was slower than for participants who selected other strategies. In Trial 2, strategies to buffer alcohol's effects were associated with a monthly 14 % decrease of alcohol-related harm. CONCLUSION: This study replicated prior findings that people experiencing homelessness and AUD regularly adopt strategies to reduce alcohol-related harm. The implementation of safer-use strategies was favorably associated with alcohol outcomes, but specific associations differed by trial and outcome. Discussion of safer-use strategies appears helpful; however, further research is needed to firmly establish how this HaRT-A component works.

Microbiological Stability of Allopurinol, Clindamycin Hydrochloride, Naltrexone Hydrochloride, Spironolactone and Ursodiol Oral Liquids Compounded in PCCA Base, SuspendIt®.

The individual physicochemical stabilities of Allopurinol, Clindamycin Hydrochloride, Naltrexone Hydrochloride, Spironolactone and Ursodiol in the proprietary suspending vehicle PCCA SuspendIt® have been previously studied and published by the author. Accordingly, Beyond-Use-Dates (BUDs) of 180 days were assigned to the five drugs based on the results of the respective studies. The data were donated to the United States Pharmacopeia (USP) for possible adoption as Official Compounded Drug Monographs. Following an extensive review process, all five studies were approved and published by the USP. However, due to a lack of microbiological stability information, the BUDs were limited to 90 days. The current study was undertaken as a follow-up project to determine the microbiological stability of these five drugs in PCCA SuspendIt® utilizing the same compounding procedures from the original studies. A stable extemporaneous product is defined as one that retains at least 90% of the initial drug concentration throughout the sampling period and is protected against microbial growth. The goal was to provide a viable, compounded alternative for Allopurinol, Clindamycin Hydrochloride, Naltrexone Hydrochloride, Spironolactone and Ursodiol in a thixotropic liquid dosage form, with an extended BUD of 6 months to meet patient needs. Given that the physical and chemical stabilities of all five drugs have been previously established and adopted by the USP as official compounded monographs, additional microbiological stability data would allow the official BUDs in the USP to be extended to 180 days to conform to the physicochemical stabilities. The current study showed that the preservative system in PCCA SuspendIt® successfully protected all the suspensions from growth of challenge microorganisms per the USP Chapter <51> AME Test. The results of the current study combined with the previous physicochemical studies demonstrate the following: Allopurinol is physically, chemically and microbiologically stable in PCCA SuspendIt for 180 days in the refrigerator and at room temperature over a bracketed allopurinol concentration range of 10 - 20 mg/mL. Clindamycin Hydrochloride is physically, chemically and microbiologically stable in PCCA SuspendIt for 180 days in the refrigerator and at room temperature at a concentration of 10-mg/mL of clindamycin. Naltrexone Hydrochloride is physically, chemically and microbiologically stable in PCCA SuspendIt for 180 days in the refrigerator and at room temperature, over a bracketed naltrexone hydrochloride concentration range of 0.5 - 5.0 mg/mL. Spironolactone is physically, chemically and microbiologically stable in PCCA SuspendIt for 180 days in the refrigerator and at room temperature at a concentration of 5 mg/mL of spironolactone. Ursodiol is physically, chemically and microbiologically stable in PCCA SuspendIt for 180 days in the refrigerator and at room temperature, over a bracketed ursodiol concentration range of 50 - 100 mg/mL. Taken collectively, the current study in conjunction with the earlier studies provide viable, compounded alternatives for Allopurinol, Clindamycin Hydrochloride, Naltrexone Hydrochloride, Spironolactone and Ursodiol in the suspending vehicle PCCA SuspendIt in liquid dosage forms, with an extended beyond-use-date to meet patient needs.

Effect of Preadministration of Nalmefene on Sufentanil-Induced Cough During Induction of General Anesthesia in Patients Undergoing Breast Surgery: A Double-Blind Randomized Controlled Trial.

Purpose: This study was designed to investigate the effects of preadministration of nalmefene before general anesthesia induction on sufentanil-induced cough (SIC) in patients undergoing breast surgery. Patients and Methods: A total of 105 patients scheduled for elective breast surgery under general anesthesia were selected and randomly assigned into three groups: normal saline (Group C), low-dose nalmefene 0.1 µg·kg-1 (Group LN), and high-dose nalmefene 0.25 µg·kg-1 (Group HN). Sufentanil 0.5 µg·kg-1 was injected intravenously within 2 s after 5 min of intervention. The count and severity of cough within 2 min after sufentanil injection, as well as the time to first cough, were recorded. In addition, we also collected intraoperative hemodynamic data, postoperative pain scores, the incidence of receiving rescue analgesics, and side effects up to 24 h after surgery. Results: Compared to Group C, the incidence of SIC was significantly lower in Group LN and HN (64.7% vs 30.3% and 14.7%, respectively; P < 0.001), but no significant difference was observed between the two groups (P=0.126). Compared to Group C, the risk factors decreased by 53.4% (95% confidence interval [CI] =0.181-0.735, P=0.008) in Group LN and by 75.9% (95% CI=0.432-0.898, P=0.001) in Group HN. Of the patients with SIC, less frequent SIC within 2 min after induction and a lower proportion of severe coughs were observed than Group C (P < 0.05), and no difference was detected between Group LN and HN. Additionally, the onset time to the first SIC did not differ significantly between the groups. Intraoperative hemodynamic data, postoperative pain scores, and side effects in the first 24 h did not differ among the groups. Conclusion: Preadministration of nalmefene prior to induction of general anesthesia effectively suppressed SIC in patients undergoing breast surgery, without affecting intraoperative hemodynamic fluctuation and postoperative pain intensity.

Case Series of Individuals Treated With Naltrexone During Pregnancy for Opioid and/or Alcohol Use Disorder.

OBJECTIVE: There is a lack of knowledge about the relative safety and efficacy of naltrexone for the treatment of pregnant individuals with opioid and/or alcohol use disorder, including the range of outcomes, in both the pregnant individual and the infant, over the course of peripartum period. Our objective was to describe these outcomes in a cohort of pregnant individuals on naltrexone. METHODS: In this prospective case series, 7 pregnant individuals with opioid use disorder (OUD) or alcohol use disorder (AUD) treated with naltrexone were followed from pregnancy through 12 months after delivery. Clinical treatment protocols and outcomes related to safety and efficacy during pregnancy, delivery, and the postpartum period are described. RESULTS: There were 4 pregnant individuals with OUD and 3 with AUD, of which 3 were managed with oral and 4 with extended-release naltrexone. The mean gestational age at study enrollment was 21.7 (SD, 12) weeks. Of the 7 participants, there was no return to nonprescribed opioid use and 2 who experienced a return to alcohol use over the course of the study. All individuals delivered vaginally at a mean of 37 weeks gestation without any peripartum pain difficulties. Five of the individuals (71.4%) remained on naltrexone 12 months after delivery. There were no reported fetal anomalies and one preterm delivery. None of the infants developed neonatal opioid withdrawal syndrome. CONCLUSIONS: For pregnant individuals with OUD or AUD treated with naltrexone, there were low rates of return to nonprescribed use and reassuring pregnant person and infant outcomes to 12 months postpartum.

Reversal of Opioid-Induced Respiratory Depression in Healthy Volunteers: Comparison of Intranasal Nalmefene and Intranasal Naloxone.

An open-label, randomized, crossover study in healthy volunteers compared the reversal of remifentanil-induced respiratory depression by intranasal (IN) naloxone hydrochloride (4 mg) to IN nalmefene (2.7 mg) (NCT04828005). Subjects were administered a hypercapnic gas mixture which produces an elevation in minute ventilation (MV), a result of the ventilatory response to hypercapnia. Subjects breathed a hypercapnic gas mixture through a tight-fitting mask for an initial period of 46 min prior to a series of mask "holidays" introduced to reduce subject discomfort and encourage study completion. Ten minutes after initiating the hypercapnic gas mixture, a remifentanil bolus was administered, and an infusion continued for the study duration. Subjects were administered either naloxone or nalmefene 15 min after initiating the remifentanil infusion and MV monitored for 21 min followed by a mask holiday. Both nalmefene and naloxone produced a time-dependent reversal of remifentanil-induced reductions in MV measured 2.5-20 min post administration. At the primary endpoint (5 min post administration), nalmefene increases in MV (5.75 L/min) were nearly twice that produced by naloxone (3.01 L/min) (P < .0009); the point estimate favors nalmefene, demonstrating non-inferiority and superiority. In this model of opioid-induced respiratory depression, nalmefene has a more rapid onset of action than naloxone, which required 20 min to achieve a comparable reversal of respiratory depression. Both nalmefene and naloxone were well tolerated by healthy volunteers. This rapid onset of action may prove particularly valuable in an era when over 90% of fatalities are linked to synthetic opioid overdose.

Therapeutic Potential of Naltrexone in the Niche of Psychopharmacology.

NTX is FDA-approved for opiate and alcohol use disorders as anti-craving agent. It has been used successfully off-label in other psychiatric indications. Here, we shed some light on these while examining the extant evidence.

Discontinuation of medication treatment for opioid use disorder after a successful course: The discontinuation phase of the CTN-0100 (RDD) trial.

INTRODUCTION AND BACKGROUND: Buprenorphine, and extended-release naltrexone, are effective in decreasing opioid use, morbidity and mortality. The available evidence suggests that these medications should be used for long term treatment; however, patients often ask how long they need to be on medication, and whether it would be safe to discontinue. There are sparse data to guide us. The CTN-0100 trial will address this gap in our knowledge by studying participants who have decided to discontinue buprenorphine and extended-release naltrexone for OUD. RESEARCH DESIGN AND METHODS: The trial is a multicenter, randomized, non-blinded study. Participants are stable adult volunteers, on sublingual buprenorphine, extended-release buprenorphine, or extended-release naltrexone, expressing an interest in discontinuing medication. Participants on buprenorphine must be stable for at least 1 year and participants on extended-release naltrexone must be stable for at least 6 months. Participants are engaged in the study for up to 96 weeks, including a flexible taper period, and are then transitioned to follow-up within the trial. All participants are randomly assigned to the study Medical Management (MM) or to MM plus Connections (CHESS health) digital smartphone application aimed at recovery and abstinence (MMD). Sublingual Buprenorphine participants are also randomized (2 × 2 design) to a taper using either sublingual or extended-release buprenorphine. DISCUSSION/CONCLUSION: It is hoped that this trial will provide a rich source of data on management of patients discontinuing medication for opioid use disorder (MOUD) to inform future research and practice. The trial will shed light on which strategies are most likely to lead to long-term success (absence of relapse), and what participant characteristics distinguish those who can safely discontinue MOUD from those who remain at risk of relapse should they discontinue. CLINICALTRIALS: gov Identifier: NCT04464980.

A pilot randomized controlled trial of medication adherence therapy: Psychosocial leverage using a significant other (MAT-PLUS) for individuals on extended-release naltrexone.

BACKGROUND: Extended-release naltrexone (XR-NTX) is an important treatment option for individuals with opioid use disorder (OUD) and/or alcohol use disorder (AUD). However, problems with retention are a major barrier to its overall effectiveness, and interventions to improve adherence are underdeveloped. The purpose of this study was to pilot test the MAT-PLUS intervention, which combines assertive outreach and involvement of a treatment significant other (TSO) to improve adherence to XR-NTX. METHODS: Adults (N = 41) seeking treatment for OUD and/or AUD with XR-NTX were recruited from an inpatient addiction treatment center and randomized to the MAT-PLUS intervention or treatment as usual (TAU) for 16-weeks. TSOs (N = 19) of individuals in the MAT-PLUS condition were also enrolled. The primary outcome was the number of XR-NTX doses received and relapse to regular heavy use (opioid or alcohol) was a secondary outcome. RESULTS: Participants in the MAT-PLUS group received 3.4 doses compared to 2.5 in TAU, which was significant after controlling for SUD diagnosis (p < 0.05). Rates of receipts of all prescribed doses were 61.1 % in MAT-PLUS compared to 30.4 % in TAU, giving an NNT of 3.3. Relapse rates and days of heavy use did not vary by treatment group. CONCLUSIONS: This study demonstrates preliminary efficacy of the MAT-PLUS intervention for XR-NTX adherence. This study was limited by its small sample size and future research should broaden the intervention to apply across medications for SUD in larger samples. Family support with an emphasis on medication adherence has strong potential for improving addiction treatment outcomes.

Rapid Initiation of Injection Naltrexone for Opioid Use Disorder: A Stepped-Wedge Cluster Randomized Clinical Trial.

Importance: Injectable extended-release (XR)-naltrexone is an effective treatment option for opioid use disorder (OUD), but the need to withdraw patients from opioid treatment prior to initiation is a barrier to implementation. Objective: To compare the effectiveness of the standard procedure (SP) with the rapid procedure (RP) for XR-naltrexone initiation. Design, Setting, and Participants: The Surmounting Withdrawal to Initiate Fast Treatment with Naltrexone study was an optimized stepped-wedge cluster randomized trial conducted at 6 community-based inpatient addiction treatment units. Units using the SP were randomly assigned at 14-week intervals to implement the RP. Participants admitted with OUD received the procedure the unit was delivering at the time of their admission. Participant recruitment took place between March 16, 2021, and July 18, 2022. The last visit was September 21, 2022. Interventions: Standard procedure, based on the XR-naltrexone package insert (approximately 5-day buprenorphine taper followed by a 7- to 10-day opioid-free period and RP, defined as 1 day of buprenorphine at minimum necessary dose, 1 opioid-free day, and ascending low doses of oral naltrexone and adjunctive medications (eg, clonidine, clonazepam, antiemetics) for opioid withdrawal. Main Outcomes and Measures: Receipt of XR-naltrexone injection prior to inpatient discharge (primary outcome). Secondary outcomes included opioid withdrawal scores and targeted safety events and serious adverse events. All analyses were intention-to-treat. Results: A total of 415 participants with OUD were enrolled (mean [SD] age, 33.6 [8.48] years; 205 [49.4%] identified sex as male); 54 [13.0%] individuals identified as Black, 91 [21.9%] as Hispanic, 290 [69.9%] as White, and 22 [5.3%] as multiracial. Rates of successful initiation of XR-naltrexone among the RP group (141 of 225 [62.7%]) were noninferior to those of the SP group (68 of 190 [35.8%]) (odds ratio [OR], 3.60; 95% CI, 2.12-6.10). Withdrawal did not differ significantly between conditions (proportion of days with a moderate or greater maximum Clinical Opiate Withdrawal Scale score (>12) for RP vs SP: OR, 1.25; 95% CI, 0.62-2.50). Targeted safety events (RP: 12 [5.3%]; SP: 4 [2.1%]) and serious adverse events (RP: 15 [6.7%]; SP: 3 [1.6%]) were infrequent but occurred more often with RP than SP. Conclusions and Relevance: In this trial, the RP of XR-naltrexone initiation was noninferior to the standard approach and saved time, although it required more intensive medical management and safety monitoring. The results of this trial suggest that rapid initiation could make XR-naltrexone a more viable treatment for patients with OUD. Trial Registration: ClinicalTrials.gov Identifier: NCT04762537.

Low-dose naltrexone for post-COVID fatigue syndrome: a study protocol for a double-blind, randomised trial in British Columbia.

INTRODUCTION: A significant proportion of individuals suffering from post COVID-19 condition (PCC, also known as long COVID) can present with persistent, disabling fatigue similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and post-viral fatigue syndromes. There remains no clear pharmacological therapy for patients with this subtype of PCC, which can be referred to as post-COVID fatigue syndrome (PCFS). A low dose of the opioid antagonist naltrexone (ie, low-dose naltrexone (LDN)) has emerged as an off-label treatment for treating fatigue and other symptoms in PCC. However, only small, non-controlled studies have assessed LDN in PCC, so randomised trials are urgently required. METHODS AND ANALYSIS: A prospective, randomised, double-blind, parallel arm, placebo-controlled phase II trial will be performed to assess the efficacy of LDN for improving fatigue in PCFS. The trial will be decentralised and open to eligible individuals throughout the Canadian province of British Columbia (BC). Participants will be recruited through the province-wide Post-COVID-19 Interdisciplinary Clinical Care Network (PC-ICCN) and research volunteer platform (REACH BC). Eligible participants will be 19-69 years old, have had a confirmed or physician-suspected SARS-CoV-2 infection at least 3 months prior and meet clinical criteria for PCFS adapted from the Institute of Medicine ME/CFS criteria. Individuals who are taking opioid medications, have a history of ME/CFS prior to COVID-19 or history of significant liver disease will be excluded. Participants will be randomised to an LDN intervention arm (n=80) or placebo arm (n=80). Participants in each arm will be prescribed identical capsules starting at 1 mg daily and follow a prespecified schedule for up-titration to 4.5 mg daily or the maximum tolerated dose. The trial will be conducted over 16 weeks, with assessments at baseline, 6, 12 and 16 weeks. The primary outcome will be fatigue severity at 16 weeks evaluated by the Fatigue Severity Scale. Secondary outcomes will include pain Visual Analogue Scale score, overall symptom severity as measured by the Patient Phenotyping Questionnaire Short Form, 7-day step count and health-related quality of life measured by the EuroQol 5-Dimension questionnaire. ETHICS AND DISSEMINATION: The trial has been authorised by Health Canada and approved by The University of British Columbia/Children's and Women's Health Centre of British Columbia Research Ethics Board. On completion, findings will be disseminated to patients, caregivers and clinicians through engagement activities within existing PCC and ME/CFS networks. Results will be published in academic journals and presented at conferences. TRIAL REGISTRATION NUMBER: NCT05430152.

Buprenorphine-naloxone vs. extended-release naltrexone for opioid use disorder in individuals with and without criminal legal involvement: A secondary analysis of the X:BOT randomized controlled trial.

INTRODUCTION: There is uncertainty about whether criminal legal involvement (CLI) impacts the effectiveness of medications for opioid use disorder (MOUD). We aimed to determine whether CLI modifies the association between buprenorphine-naloxone (BUP-NX) vs. extended-release naltrexone (XR-NTX) and MOUD treatment outcomes. METHODS: We conducted a secondary analysis of X:BOT, a 24-week multi-center randomized controlled trial comparing treatment outcomes between BUP-NX (n = 287) and XR-NTX (n = 283) in the general population. We used baseline Additional Severity-Index Lite responses to identify patients with recent CLI (n = 342), defined as active CLI and/or CLI in the past 30 days, and lifetime incarceration (n = 328). We explored recent CLI and lifetime incarceration as potential effect modifiers of BUP-NX vs. XR-NTX effectiveness on relapse, induction, and overdose. We conducted both intention-to-treat and per-protocol analyses for each outcome. RESULTS: In intention-to-treat analyses, recent CLI modified the effect of BUP-NX vs. XR-NTX on odds of successful induction (p = 0.03) and hazard of overdose (p = 0.04), but it did not modify the effect on hazard of relapse (p = 0.23). All participants experienced lower odds of successful induction with XR-NTX compared to BUP-NX, but the relative likelihood of successful induction with BUP-NX was lower than XR-NTX among individuals with recent CLI (OR: 0.25, 95 % CI: 0.13-0.47, p < 0.001) compared to those without recent CLI (OR: 0.04, 95 % CI: 0.01-0.19, p < 0.001). Participants with recent CLI experienced similar hazard of overdose with XR-NTX and BUP-NX (HR: 1.12, 95 % CI: 0.42-3.01, p = 0.82), whereas those without recent CLI experienced greater hazard of overdose with XR-NTX compared to BUP-NX (HR: 12.60, 95 % CI: 1.62-98.03, p = 0.02). In per-protocol analyses, recent CLI did not modify the effect of MOUD on hazard of overdose (p = 0.10) or relapse (p = 0.41). Lifetime incarceration did not modify any outcome. CONCLUSIONS: Compared to individuals without recent CLI, individuals with recent CLI experienced decreased relative effectiveness of BUP-NX compared to XR-NTX for induction and overdose outcomes. This highlights the importance of considering the impact of recent CLI on opioid use disorder treatment outcomes. Future research should explore the mechanisms through which recent CLI modifies MOUD effectiveness and aim to improve MOUD effectiveness for individuals with recent CLI.

Bioabsorbable, subcutaneous naltrexone implants mitigate fentanyl-induced respiratory depression at 3 months-A pilot study in male canines.

The aim of this study is to determine if extended-release, bioabsorbable, subcutaneous naltrexone (NTX) implants can mitigate respiratory depression after an intravenous injection (IV) of fentanyl. Six different BIOabsorbable Polymeric Implant Naltrexone (BIOPIN) formulations, comprising combinations of Poly-d,l-Lactic Acid (PDLLA) and/or Polycaprolactone (PCL-1 or PCL-2), were used to create subcutaneous implants. Both placebo and naltrexone implants were implanted subcutaneously in male dogs. The active naltrexone implants consisted of two doses, 644 mg and 1288 mg. A challenge with IV fentanyl was performed in 33 male dogs at 97-100 days after implantation. Following the administration of a 30 µg/kg intravenous fentanyl dose, the placebo cohort manifested a swift and profound respiratory depression with a ~50% reduction in their pre-dose respiratory rate (RR). The BIOPIN NTX-implanted dogs were exposed to escalating doses of intravenous fentanyl (30 µg/kg, 60 µg/kg, 90 µg/kg, and 120 µg/kg). In contrast, the dogs implanted with the BIOPIN naltrexone implants tolerated doses up to 60 µg/kg without significant respiratory depression (<50%) but had severe respiratory depression with fentanyl doses of 90 µg/kg and especially at 120 µg/kg. Bioabsorbable, extended-release BIOPIN naltrexone implants are effective in mitigating fentanyl-induced respiratory depression in male canines at about 3 months after implantation. This technology may also have potential for mitigating fentanyl-induced respiratory depression in humans.