Effects of perioperative low-dose naloxone on the immune system in patients undergoing laparoscopic-assisted total gastrectomy: a randomized controlled trial.

BACKGROUND: Low immune function after laparoscopic total gastrectomy puts patients at risk of infection-related complications. Low-dose naloxone (LDN) can improve the prognosis of patients suffering from chronic inflammatory diseases or autoimmune diseases. The use of LDN during perioperative procedures may reduce perioperative complications. The purpose of this study was to examine the effects of LDN on endogenous immune function in gastric cancer patients and its specific mechanisms through a randomized controlled trial. METHODS: Fifty-five patients who underwent laparoscopic-assisted total gastrectomy were randomly assigned to either a naloxone group (n = 23) or a nonnaloxone group (n = 22). Patients in the naloxone group received 0.05 µg/kg-1.h- 1naloxone from 3 days before surgery to 5 days after surgery via a patient-controlled intravenous injection (PCIA) pump, and patients in the nonnaloxone group did not receive special treatment. The primary outcomes were the rates of postoperative complications and immune function assessed by NK cell, CD3+ T cell, CD4+ T cell, CD8+ T cell, WBC count, neutrophil percentage, and IL-6 and calcitonin levels. The secondary outcomes were the expression levels of TLR4 (Toll-like receptor), IL-6 and TNF-α in gastric cancer tissue. RESULTS: Compared with the nonnaloxone group, the naloxone group exhibited a lower incidence of infection (in the incision, abdomen, and lungs) (P < 0.05). The numbers of NK cells and CD8+ T cells in the naloxone group were significantly greater than those in the nonnaloxone group at 24 h after surgery (P < 0.05) and at 96 h after surgery (P < 0.05). Compared with those in the nonnaloxone group, the CD3 + T-cell (P < 0.05) and CD4 + T-cell (P < 0.01) counts were significantly lower in the naloxone group 24 h after surgery. At 24 h and 96 h after surgery, the WBC count (P < 0.05) and neutrophil percentage (P < 0.05) were significantly greater in the nonnaloxone group. The levels of IL-6 (P < 0.05) and calcitonin in the nonnaloxone group were significantly greater at 24 h after surgery. At 24 h following surgery, the nonnaloxone group had significantly greater levels of IL-6 (P < 0.05) and calcitonin than did the naloxone group. Compared with those in the naloxone group, the expression levels of TLR4 (P < 0.05) in gastric cancer tissue in the naloxone group were greater; however, the expression levels of IL-6 (P < 0.01) and TNF-α (P < 0.01) in the naloxone group were greater than those in the nonnaloxone group. CONCLUSION: Laparoscopic total gastrectomy patients can benefit from 0.05 ug/kg- 1. h- 1 naloxone by reducing their risk of infection. It is possible that LDN alters the number of cells in lymphocyte subpopulations, such as NK cells, CD3 + T cells, and CD4 + T cells, and the CD4+/CD8 + T-cell ratio or alters TLR4 receptor expression in immune cells, thereby altering immune cell activity. TRIAL REGISTRATION: The trial was registered at the Chinese Clinical Trial Registry on 24/11/2023 (ChiCTR2300077948).

A case of naltrexone-induced acute eosinophilic pneumonia.

Acute eosinophilic pneumonia (AEP) is a rare cause of acute respiratory failure. Clinical presentations can range from dyspnoea, fever and cough, to rapidly progressive and potentially fulminant respiratory failure. While its exact cause is often unknown, associations with inhalational injuries and exposures to new medications have been described.We report a case of a middle-aged, non-smoking man with a history of alcohol use disorder. He presented with 4 days of shortness of breath that started hours after taking injectable naltrexone (Vivitrol). The patient had rapidly worsening hypoxaemia, necessitating emergent bronchoscopy with transbronchial biopsies and bronchoalveolar lavage which showed 66% eosinophils. The patient was intubated for the procedure and unable to get extubated due to worsening hypoxaemic respiratory failure with high fractional inspired oxygen requirements. Chest radiograph showed worsening lung infiltrates and with a high index of suspicion for AEP, he was started empirically on methylprednisolone. He had rapid improvement in his respiratory status and was extubated on day 5 of admission then discharged on day 8. Histopathological examination confirmed acute/subacute eosinophilic pneumonia. A 3-week post-discharge follow-up chest radiograph confirmed the full resolution of pulmonary infiltrates.Naltrexone-induced AEP is rare, with only six other cases reported in the literature. Careful history taking and prompt evaluation for AEP are important given the potential for rapid progression to acute hypoxic respiratory failure and the excellent response to steroid treatment.

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.

Potential Therapeutic Benefit of Low Dose Naltrexone in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Role of Transient Receptor Potential Melastatin 3 Ion Channels in Pathophysiology and Treatment.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating multi-systemic chronic condition of unknown aetiology classified as an immune dysfunction syndrome and neurological disorder. The discovery of the widely expressed Transient Receptor Potential Melastatin 3 (TRPM3) as a nociceptor channel substantially targeted by certain opioid receptors, and its implication in calcium (Ca2+)-dependent Natural Killer (NK) cell immune functions has raised the possibility that TRPM3 may be pharmacologically targeted to treat characteristic symptoms of ME/CFS. Naltrexone hydrochloride (NTX) acts as an antagonist to the mu (µ)-opioid receptor thus negating its inhibitory function on TRPM3. Based on the benefits reported by patients on their symptoms, low dose NTX (LDN, 3.0-5.0 mg/day) treatment seems to offer some potential benefit suggesting that its effect may be targeted towards the pathomechanism of ME/CFS. As there is no literature confirming the efficacy of LDN for ME/CFS patients in vitro, this study investigates the potential therapeutic effect of LDN in ME/CFS patients. TRPM3 ion channel activity was measured after modulation with Pregnenolone sulfate (PregS) and ononetin in NK cells on 9 ME/CFS patients taking LDN and 9 age- and sex-matched healthy controls using whole-cell patch-clamp technique. We report that ME/CFS patients taking LDN have restored TRPM3-like ionic currents in NK cells. Small ionic currents with a typical TRPM3-like outward rectification were measured after application of PregS, a TRPM3-agonist, in NK cells from patients taking LDN. Additionally, PregS-evoked ionic currents through TRPM3 were significantly modulated by ononetin, a TRPM3-antagonist, in NK cells from ME/CFS patients taking LDN. These data support the hypothesis that LDN may have potential as a treatment for ME/CFS by characterising the underlying regulatory mechanisms of LDN treatment involving TRPM3 and opioid receptors in NK cells. Finally, this study may serve for the repurpose of marketed drugs, as well as support the approval of prospective randomized clinical studies on the role and dose of NTX in treating ME/CFS patients.

Peripheral Opioid Receptor Blockade Enhances Epithelial Damage in Piroxicam-Accelerated Colitis in IL-10-Deficient Mice.

Mucosal CD4+ T lymphocytes display a potent opioid-mediated analgesic activity in interleukin (IL)-10 knockout mouse model of inflammatory bowel diseases (IBD). Considering that endogenous opioids may also exhibit anti-inflammatory activities in the periphery, we examined the consequences of a peripheral opioid receptor blockade by naloxone-methiodide, a general opioid receptor antagonist unable to cross the blood-brain barrier, on the development of piroxicam-accelerated colitis in IL-10-deficient (IL-10-/-) mice. Here, we show that IL-10-deficient mice treated with piroxicam exhibited significant alterations of the intestinal barrier function, including permeability, inflammation-related bioactive lipid mediators, and mucosal CD4+ T lymphocyte subsets. Opioid receptor antagonization in the periphery had virtually no effect on colitis severity but significantly worsened epithelial cell apoptosis and intestinal permeability. Thus, although the endogenous opioid tone is not sufficient to reduce the severity of colitis significantly, it substantially contributes to the protection of the physical integrity of the epithelial barrier.

Population Pharmacokinetics of Olanzapine and Samidorphan When Administered in Combination in Healthy Subjects and Patients With Schizophrenia.

A combination of olanzapine and samidorphan was recently approved by the US Food and Drug Administration for the treatment of patients with schizophrenia or bipolar I disorder. Population pharmacokinetic models for olanzapine and samidorphan were developed using data from 11 clinical studies in healthy subjects or patients with schizophrenia. A 2-compartment disposition model with first-order absorption and elimination and a lag time for absorption adequately described concentration-time profiles of both olanzapine and samidorphan. Age, sex, race, smoking status, and body weight were identified as covariates that impacted the pharmacokinetics of olanzapine. A moderate effect of body weight on samidorphan pharmacokinetics was identified by the model but was not considered clinically meaningful. The effects of food, hepatic or renal impairment, and coadministration with rifampin on the pharmacokinetics of olanzapine and samidorphan, as estimated by the population pharmacokinetic analysis, were consistent with findings from dedicated clinical studies designed to evaluate these specific covariates of interest. Food intake did not have a clinically relevant effect on the pharmacokinetics of olanzapine or samidorphan. Consistent with the known metabolic pathways for olanzapine (primarily via uridine 5'-diphospho-glucuronosyltransferase-mediated direct glucuronidation and cytochrome P450 [CYP]-mediated oxidation) and for samidorphan (predominantly mediated by CYP3A4), coadministration of olanzapine and samidorphan with rifampin, a strong inducer of CYP3A4 and an inducer of uridine 5'-diphospho-glucuronosyltransferase enzymes, significantly decreased the systemic exposure of both olanzapine and samidorphan. Severe renal impairment or moderate hepatic impairment resulted in a modest increase in olanzapine and samidorphan exposure.

Retrospective analysis of heroin detoxification with buprenorphine in a psychiatric hospital in Japan.

AIM: We assessed the efficacy of buprenorphine replacement taper therapy in a psychiatric hospital in Japan. METHODS: Based on the medical records, a retrospective analysis was performed to evaluate the outcomes of buprenorphine replacement taper therapy in 106 subjects with heroin dependence. RESULTS: We found that replacement and taper therapy with buprenorphine could significantly reduce withdrawal symptoms during detoxification. In addition, the completion rate of detoxification was significantly improved and the length of hospital stay was significantly reduced relative to those who received conventional treatment without buprenorphine. However, the readmission rate increased after the introduction of detoxication therapy with buprenorphine. CONCLUSION: The present findings suggest not only the efficacy and safety of buprenorphine replacement and taper therapy, but also the requirement for maintenance therapy for individuals with heroin dependence.

Deprescribing Opioids in Chronic Non-cancer Pain: Systematic Review of Randomised Trials.

BACKGROUND: Deprescribing, the process of reducing or discontinuing unnecessary or harmful medicines is an essential part of clinical practice. OBJECTIVE: To evaluate the efficacy of interventions designed to deprescribe opioid analgesics for pain relief in patients with chronic non-cancer pain. METHODS: We searched electronic databases, including clinical trial registries, from database inception to 13th January 2020 without restrictions, and conducted citation tracking. Our systematic review included randomised controlled trials (RCTs) evaluating interventions reducing the prescription, or use of opioid analgesics in patients with chronic pain versus control. Inventions could be aimed at the patient, clinician, or both. We excluded trials enrolling patients with cancer or illicit drug use. Two authors independently screened and extracted data. Outcome follow-up timepoints were short (≤ 3 months), intermediate (> 3 but < 12 months) or long (≥ 12 months) term. Primary outcome was the reduction in opioid dose [morphine milligram equivalent (MME) mg/day]. Methodological quality was assessed using the Cochrane Risk of Bias Tool. RESULTS: We included ten patient-focused RCT interventions (n = 835; median 37 participants) and 2 testing clinician-focused interventions (n = 291 clinicians); none at low risk of bias. Patient-focused interventions did not reduce opioid dose in the intermediate term [e.g. dose reduction protocol, mean difference (MD) - 19.9 MME, 95% CI - 107.5 to 67.7], nor did they increase the number of participants who ceased their dose, or increase the risk of serious adverse events or adverse events. One clinician intervention of education plus decision tools versus decision tools alone reduced the number of opioid prescriptions (risk difference (RD) - 0.1, 95% CI - 0.2 to - 0.1), dose (MD - 5.3 MME, 95% CI - 6.2 to - 4.5) and use (RD - 0.1, 95% CI - 0.1 to - 0.0) in the long term. LIMITATIONS: Study heterogeneity prevented meta-analysis. CONCLUSION: The small number of studies and heterogeneity prevented firm conclusions to recommend any one opioid-analgesic-deprescribing strategy in patients with chronic pain. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42017068422.

Comparison of buprenorphine and methadone in the management of maternal opioid use disorder in full term pregnancies.

Objectives To compare pregnancy outcomes with medication assisted treatment using. methadone or buprenorphine in term mothers with opioid use disorder. Methods A cohort of women receiving medication assisted treatment with either methadone or buprenorphine were identified from delivery records over a 10-year period. Women were excluded with delivery <37 weeks, multiple gestations, or a known anomalous fetus. Maternal demographics, medications, mode of delivery, birthweight, newborn length of stay, and neonatal abstinence syndrome were extracted. The study was IRB approved and a p-value of <0.05 was significant. Results There were 260 women, 140 (53.8%) with methadone use and 120 (46.2%) with buprenorphine use. Groups were similar for maternal age, race, parity, homeless rate, tobacco use, mode of delivery and incidence of neonatal abstinence syndrome. The methadone group had a lower mean newborn birthweight (2874±459 g) and a greater incidence of low birth weight (11.4%) than the buprenorphine group (3282±452 g; p<0.001 and 2.5%; p=0.006). The incidence of neonatal abstinence syndrome was similar between groups (97% methadone vs. 92.5% buprenorphine; p=0.08). The methadone group had a longer newborn length of stay (11.4+7.4 days) and more newborn treatment with morphine (44.6%) than the buprenorphine group (8.2+4.4 days; p<0.001 and 24.2%; p<0.001). Maternal methadone use was an independent predictor for a newborn length of hospital stay >7 days (OR 3.61; 95% confidence interval 1.32-9.86; p=0.01). Conclusions Medication assisted treatment favors buprenorphine use when compared to. methadone with an increased birthweight, reduced need for newborn treatment, and a shorter newborn length of stay in term infants.

Mannosylated glycoliposomes for the delivery of a peptide kappa opioid receptor antagonist to the brain.

Dynantin is a potent and selective synthetic polypeptide kappa opioid receptor antagonist which has potential antidepressant and anxiolytic-like therapeutic applications, however its clinical development has been hampered by plasma stability issues and poor penetration of the blood brain barrier. Targeted liposome delivery systems represent a promising and non-invasive approach to improving the delivery of therapeutic agents across the blood brain barrier. As part of our work focused on targeted drug delivery, we have developed a novel mannosylated liposome system. Herein, we investigate these glycoliposomes for the targeted delivery of dynantin to the central nervous system. Cholesterol was tested and optimized as a formulation excipient, where it improved particle stability as measured via particle size, entrapment and ex vivo plasma stability of dynantin. The in vitro PRESTO-TANGO assay system was used to confirm that glycoliposomal entrapment did not impact the affinity or activity of the peptide at its receptor. Finally, in vivo distribution studies in mice showed that the mannosylated glycoliposomes significantly improved delivery of dynantin to the brain. Overall, the results clearly demonstrate the potential of our glycoliposomes as a targeted delivery system for therapeutic agents of the central nervous system.

New directions in the treatment of opioid withdrawal.

The treatment of opioid withdrawal is an important area of clinical concern when treating patients with chronic, non-cancer pain, patients with active opioid use disorder, and patients receiving medication for opioid use disorder. Current standards of care for medically supervised withdrawal include treatment with µ-opioid receptor agonists, (eg, methadone), partial agonists (eg, buprenorphine), and α2-adrenergic receptor agonists (eg, clonidine and lofexidine). Newer agents likewise exploit these pharmacological mechanisms, including tramadol (µ-opioid receptor agonism) and tizanidine (α2 agonism). Areas for future research include managing withdrawal in the context of stabilising patients with opioid use disorder to extended-release naltrexone, transitioning patients with opioid use disorder from methadone to buprenorphine, and tapering opioids in patients with chronic, non-cancer pain.

Can Predictive Modeling Tools Identify Patients at High Risk of Prolonged Opioid Use After ACL Reconstruction?

BACKGROUND: Machine-learning methods such as the Bayesian belief network, random forest, gradient boosting machine, and decision trees have been used to develop decision-support tools in other clinical settings. Opioid abuse is a problem among civilians and military service members, and it is difficult to anticipate which patients are at risk for prolonged opioid use. QUESTIONS/PURPOSES: (1) To build a cross-validated model that predicts risk of prolonged opioid use after a specific orthopaedic procedure (ACL reconstruction), (2) To describe the relationships between prognostic and outcome variables, and (3) To determine the clinical utility of a predictive model using a decision curve analysis (as measured by our predictive system's ability to effectively identify high-risk patients and allow for preventative measures to be taken to ensure a successful procedure process). METHODS: We used the Military Analysis and Reporting Tool (M2) to search the Military Health System Data Repository for all patients undergoing arthroscopically assisted ACL reconstruction (Current Procedure Terminology code 29888) from January 2012 through December 2015 with a minimum of 90 days postoperative follow-up. In total, 10,919 patients met the inclusion criteria, most of whom were young men on active duty. We obtained complete opioid prescription filling histories from the Military Health System Data Repository's pharmacy records. We extracted data including patient demographics, military characteristics, and pharmacy data. A total of 3.3% of the data was missing. To curate and impute all missing variables, we used a random forest algorithm. We shuffled and split the data into 80% training and 20% hold-out sets, balanced by outcome variable (Outcome90Days). Next, the training set was further split into training and validation sets. Each model was built on the training data set, tuned with the validation set as applicable, and finally tested on the separate hold-out dataset. We chose four predictive models to develop, at the end choosing the best-fit model for implementation. Logistic regression, random forest, Bayesian belief network, and gradient boosting machine models were the four chosen models based on type of analysis (classification). Each were trained to estimate the likelihood of prolonged opioid use, defined as any opioid prescription filled more than 90 days after anterior cruciate reconstruction. After this, we tested the models on our holdout set and performed an area under the curve analysis concordance statistic, calculated the Brier score, and performed a decision curve analysis for validation. Then, we chose the method that produced the most suitable analysis results and, consequently, predictive power across the three calculations. Based on the calculations, the gradient boosting machine model was selected for future implementation. We systematically selected features and tuned the gradient boosting machine to produce a working predictive model. We performed area under the curve, Brier, and decision curve analysis calculations for the final model to test its viability and gain an understanding of whether it is possible to predict prolonged opioid use. RESULTS: Four predictive models were successfully developed using gradient boosting machine, logistic regression, Bayesian belief network, and random forest methods. After applying the Boruta algorithm for feature selection based on a 100-tree random forest algorithm, features were narrowed to a final seven features. The most influential features with a positive association with prolonged opioid use are preoperative morphine equivalents (yes), particular pharmacy ordering sites locations, shorter deployment time, and younger age. Those observed to have a negative association with prolonged opioid use are particular pharmacy ordering sites locations, preoperative morphine equivalents (no), longer deployment, race (American Indian or Alaskan native) and rank (junior enlisted).On internal validation, the models showed accuracy for predicting prolonged opioid use with AUC greater than our benchmark cutoff 0.70; random forest were 0.76 (95% confidence interval 0.73 to 0.79), 0.76 (95% CI 0.73 to 0.78), 0.73 (95% CI 0.71 to 0.76), and 0.72 (95% CI 0.69 to 0.75), respectively. Although the results from logistic regression and gradient boosting machines were very similar, only one model can be used in implementation. Based on our calculation of the Brier score, area under the curve, and decision curve analysis, we chose the gradient boosting machine as the final model. After selecting features and tuning the chosen gradient boosting machine, we saw an incremental improvement in our implementation model; the final model is accurate, with a Brier score of 0.10 (95% CI 0.09 to 0.11) and area under the curve of 0.77 (95% CI 0.75 to 0.80). It also shows the best clinical utility in a decision curve analysis. CONCLUSIONS: These scores support our claim that it is possible to predict which patients are at risk of prolonged opioid use, as seen by the appropriate range of hold-out analysis calculations. Current opioid guidelines recommend preoperative identification of at-risk patients, but available tools for this purpose are crude, largely focusing on identifying the presence (but not relative contributions) of various risk factors and screening for depression. The power of this model is that it will permit the development of a true clinical decision-support tool, which risk-stratifies individual patients with a single numerical score that is easily understandable to both patient and surgeon. Probabilistic models provide insight into how clinical factors are conditionally related. Not only will this gradient boosting machine be used to help understand factors contributing to opiate misuse after ACL reconstruction, but also it will allow orthopaedic surgeons to identify at-risk patients before surgery and offer increased support and monitoring to prevent opioid abuse and dependency. LEVEL OF EVIDENCE: Level III, therapeutic study.

Transitioning a patient from injectable opioid agonist therapy to sublingual buprenorphine/naloxone for the treatment of opioid use disorder using a microdosing approach.

In the wake of North America's opioid crisis, access to evidence-based treatment for opioid use disorder (OUD) is of critical importance. While buprenorphine/naloxone and methadone are currently indicated as first-line medications for the treatment of OUD, there are a proportion of individuals who do not benefit from these therapies. Recent Canadian guidelines suggest the use of alternate therapies, including slow-release oral morphine or injectable opioid agonist therapy (iOAT) for individuals unsuccessful with either methadone or buprenorphine/naloxone. While the guidelines highlight the need to intensify OUD treatment as disease severity increases, equally important is the consideration for deintensification of treatment (eg, from iOAT to an oral opioid agonist treatment (OAT) option) following successful stabilisation. Literature addressing how best to accomplish this, however, is currently lacking. Accordingly, the case presented here describes a patient that successfully transitions from iOAT to oral buprenorphine/naloxone using a novel induction approach termed microdosing.

Genetic knockout of the G protein-coupled estrogen receptor 1 facilitates the acquisition of morphine-induced conditioned place preference and aversion in mice.

Drug addiction is considered the pathological usurpation of normal learning and memory. G protein-coupled estrogen receptor 1 (GPER1) plays an important role in normal learning and memory, but the effect of GPER1 on addiction-related pathological memory has not been reported. Our study used GPER1 knockout (GPER1 KO) and wild-type (WT) mice to compare the sensitivity differences of morphine- and sucrose-induced conditioned place preference (CPP) and naloxone-induced conditioned place aversion (CPA), and differences in dopamine (DA) content in the nucleus accumbens (NAc) were determined by high performance liquid chromatography (HPLC). The results showed that GPER1 KO mice showed higher sensitivity to morphine-induced CPP and naloxone-induced CPA, and corresponding to the behavioral effect, the DA content in the NAc of GPER1 KO mice was significantly higher than that of WT mice. Interestingly, the sensitivity of GPER1 KO mice to sucrose-induced CPP did not differ from that of the WT mice, and there was no significant difference in the DA content in the NAc between the two genotypes of mice. GPER1 knockout promoted the formation of morphine addiction-related positive and aversive memory, and its molecular biological mechanism may be associated with increased DA content in the NAc. Therefore, GPER1 plays an important role in the formation of addiction-related pathological memory and may become a potential molecular target for drug addiction therapy.

Case Series: Rapid Induction Onto Long Acting Buprenorphine Injection for High Potency Synthetic Opioid Users.

BACKGROUND AND OBJECTIVES: Highly potent synthetic opioids (HPSO) are increasingly responsible for opioid overdose deaths in the United States. METHODS: In an open-label, uncontrolled trial to test the feasibility of extended-release buprenorphine (BXR) injection treatment of heroin-using individuals with opioid use disorder testing positive for HPSO, participants were enrolled and began an induction with sublingual BXR (n = 5). During the induction, ancillary medications (clonidine, clonazepam, zolpidem, and prochlorperazine) were provided for breakthrough opioid withdrawal symptoms. RESULTS: Two participants received the BXR injection on the second day of the induction and three participants on the third day. DISCUSSION AND CONCLUSION: All five participants were retained at least 1-month postinduction. SCIENTIFIC SIGNIFICANCE: It may be feasible to provide BXR treatment to HPSO-positive heroin users rapidly to achieve clinical stabilization. (Am J Addict 2020;00:00-00).

One million screened: Scaling up SBIRT and buprenorphine treatment in hospital emergency departments across Maryland.

PURPOSE: Identification of problematic alcohol use and substance use in the population has been a clinical challenge, especially during the heightened years of the opioid epidemic. Bringing Screening, Brief Intervention, and Referral to Treatment (SBIRT) to scale in medical settings, such as hospital emergency departments (EDs) could facilitate broad identification of substance use disorders, timely delivery of brief interventions, and successful linkages to treatment. PROCEDURES: This large-scale data analysis pulled electronic health record (EHR) data from 23 hospitals in the state of Maryland for over 1 million patient visits between July 2014 and November 2018. FINDINGS: Of the 1,097,142 ED patients screened, 17.2% screened positive for problematic alcohol or any drug use in the previous 12 months. During this same period, 79,899 brief interventions were delivered, 15,961 referrals to outpatient treatment were made and 38.3% of those were successfully linked to treatment. Of the 950 patients exhibiting withdrawal symptoms, over two-thirds patients (70.1%; n = 666) were administered buprenorphine, 94.6% (n = 630) accepted a referral to buprenorphine treatment in the community, and 64.6% (n = 430) attended their first outpatient buprenorphine treatment visit. A total of 2382 patients presented to the ED with a suspected opioid overdose, over half were referred to the intervention program (53.8%) and 63.2% were successfully engaged by the PRCs in the ED. CONCLUSIONS: This analysis supports the scalability of SBIRT in hospital EDs and presents an implementation model that can be replicated in EDs nationwide.

Prevention and management of diarrhea associated with naldemedine among patients receiving opioids: a retrospective cohort study.

BACKGROUND: Naldemedine, a novel peripherally-acting mu-opioid receptor antagonist, has improved opioid-induced constipation in randomized controlled trials. The most frequent adverse event of naldemedine is diarrhea, which can cause abdominal pain and often leads to treatment discontinuation. We aimed to identify risk factors and appropriate management strategies for key adverse events including diarrhea associated with naldemedine, since those have not been extensively studied. METHODS: We conducted a multi-center retrospective cohort study. Eligible patients had cancer, had undergone palliative care at participating centers, had been prescribed regular opioids, and had taken at least one dose of naldemedine between June 2017 and March 2018. The primary endpoint was the incidence of diarrhea according to baseline characteristics. Secondary endpoints included the duration of naldemedine administration, daily defecation counts before and after starting naldemedine, duration and severity of diarrhea as an adverse event of naldemedine, other adverse events, and the incidence of constipation within 7 days after recovery from diarrhea. We defined patients who started naldemedine within three days of starting a regularly prescribed opioid as the early group, and the remainder as the late group. RESULTS: Among 103 patients who received naldemedine, 98 fulfilled the eligibility criteria. The median age was 68 years and 48% of the patients were female. Median performance status was 3, and the median oral intake was 50%. The median duration of naldemedine administration and overall survival were 25 and 64 days, respectively. The incidence of diarrhea in the early group (n = 26) was significantly lower than in the late group (n = 72) (3.9% vs. 22.2%, p = 0.02). Daily defecation counts increased after late (median 0.43 to 0.88, p < 0.001), but remained stable after early naldemedine administration (median 1.00 to 1.00, p = 0.34). Constipation after the diarrhea was resolved was common (53%), especially among patients who stopped naldemedine (78%). The diarrhea was improved within three days in 92% of patients who stopped other laxatives. CONCLUSIONS: The early administration of naldemedine is beneficial because it reduces adverse events including diarrhea. Diarrhea caused by naldemedine can be effectively managed by stopping other laxatives while continuing naldemedine.

A Practical Approach for the Management of the Mixed Opioid Agonist-Antagonist Buprenorphine During Acute Pain and Surgery.

The use of buprenorphine, a mixed opioid agonist-antagonist, for the management of chronic pain and/or opioid use disorder is increasing. As such, medical providers will more frequently encounter patients on this therapy. In this paper, we synthesize existing knowledge (derived through keyword searches using MEDLINE databases) in a novel conceptual framework for patients on buprenorphine presenting with acute pain or for those requiring surgical or invasive procedures. This framework is based on three unique domains: the patient, the features of the acute pain insult, and the environment. We discuss important considerations regarding the unique aspects of buprenorphine formulations and dosing, and we describe the importance of multidisciplinary planning and multimodal analgesic strategies. We also highlight important differences in management strategies based upon the presence or absence of opioid use disorder. All medical providers must be prepared to guide the patient on buprenorphine safely through the acute care episode, which includes adequate treatment of acute pain and avoidance of iatrogenic harm, including both short-term complications (eg, respiratory depression) and long-term complications (eg, relapse to opioid use).

Subcutaneous methylnaltrexone for opioid-induced constipation in advanced-illness patients with or without active cancer.

Aim: To evaluate methylnaltrexone for opioid-induced constipation in patients with and without cancer. Methods: This post hoc analysis comprises two Phase III, multicenter, double-blind, randomized studies of advanced-illness patients who received methylnaltrexone subcutaneous injection or placebo. Results: Significantly more patients treated with methylnaltrexone than placebo experienced laxation within 4 (cancer = 55.5 vs 15.5%; noncancer = 55.6 vs 12.8%) and 24 (cancer = 64.7 vs 29.8%; noncancer = 64.4 vs 30.8%) h after the first dose (p < 0.01 vs placebo). Regardless of cancer status, methylnaltrexone reduced median time to laxation and improved constipation relief without impacting opioid analgesia or withdrawal symptoms. Conclusion: Methylnaltrexone provided significant improvements in opioid-induced constipation over placebo in advanced-illness patients with and without cancer. Clinical trial registration numbers: study 301: NCT00401362; study 302: NCT00402038.

The Effect of Ultra-low-dose Intrathecal Naloxone on Pain Intensity After Lumbar Laminectomy With Spinal Fusion: A Randomized Controlled Trial.

BACKGROUND: Despite advances in pain management, several patients continue to experience severe acute pain after lumbar spine surgery. The aim of this study was to assess the safety and effectiveness of single ultra-low-dose intrathecal (IT) naloxone in combination with IT morphine for reducing pain intensity, pruritus, nausea, and vomiting in patients undergoing lumbar laminectomy with spinal fusion. MATERIALS AND METHODS: In this double-blind trial, patients scheduled for lumbar laminectomy with spinal fusion were randomly assigned to receive single ultra-low-dose IT naloxone (20 µg) and IT morphine (0.2 mg) (group M+N) or IT morphine (0.2 mg) alone (group M). The severity of postoperative pain, pruritus and nausea, and frequency of vomiting were assessed at recovery from anesthesia and, subsequently, at 1, 3, 6, 12, and 24 hours postoperatively using an 11-point (0-10) visual analogue scale. RESULTS: A total of 77 patients completed the study, and there were significant differences in postoperative pain, pruritus, and nausea visual analogue scale between the groups (P<0.05). After adjusting for body mass index and surgery duration, IT naloxone administration reduced the pain score (coefficient=1.84; 95% confidence interval [CI], 1.05-2.63; P<0.001), and the scores of pruritus and nausea (coefficient=0.9; 95% CI, 0.44-1.37; P<0.001 and coefficient=0.71; 95% CI, 0.12-1.31; P=0.02, respectively) compared with IT morphine alone. No serious adverse effects were observed. CONCLUSIONS: The addition of ultra-low-dose IT naloxone to IT morphine provides excellent postoperative pain management and effectively controls pruritus and nausea in patients undergoing laminectomy with spinal fusion.