Novel Therapeutic and Program-Based Approaches to Opioid Use Disorders.

Opioid use disorder continues to drive overdose deaths in many countries, including the United States. Illicit fentanyl and its analogues have emerged as key contributors to the complications and mortality associated with opioid use disorder. Medications for opioid use disorder treatment, such as methadone and buprenorphine, are safe and substantially reduce opioid use, infectious complications, and mortality risk, but remain underutilized. Polysubstance use and emerging substances such as xylazine and designer benzodiazepines create additional treatment challenges. Recent clinical and policy innovations in treatment delivery, including telemedicine, bridge clinics, and expanded models for accessing methadone have the potential to increase access to life-saving care for people living with opioid use disorder.

Benefits and challenges experienced by participants on long-term methadone maintenance treatment in China: a qualitative study.

BACKGROUND: Methadone maintenance treatment (MMT) has been implemented in China for nearly two decades, with a significant decrease in the number of participants in recent years. However, there is a lack of comprehensive research focusing on the long-term effectiveness in the context of this decline, especially from the perspectives of MMT participants themselves. This study aims to address this gap by examining the benefits and challenges experienced by long-term MMT participants in China, to uncover potential causes of the decrease in participant numbers and to improve the effectiveness of the program. METHODS: We conducted semi-structured interviews with 21 long-term MMT participants (treatment duration ≥ 5 years) recruited through purposive sampling from 6 MMT clinics in the Guangdong Province, China, between December 2021 and August 2022. Thematic analysis was employed to analyze the transcribed interviews. Two analysts independently coded the data, and a third researcher double-coded 20% of transcripts to ensure intercoder reliability. RESULTS: Overall, participants corroborated the notable decline in MMT participants during their long-term MMT, citing death, arrest, and self-perceived abstinence from heroin, as their perceived driving factors. They reported positive changes in their health, family relationships, and social functioning. However, they identified economic hardship as their greatest challenge associated with MMT, further exacerbated by other barriers including the conflict of clinic opening hours and working schedules, discrimination from employers, and COVID-19-related restrictions. Additionally, participants identified issues with dose adjustment and emergency treatment continuation. CONCLUSIONS: This study outlines the overall improvement in the quality of life of long-term MMT participants. However, it highlights the need for official guidelines for dose adjustment and emergency treatment continuation as well as the provision of health education, job referrals, and flexibility of clinic opening times to facilitate the return to society receiving participants. Establishing a follow-up mechanism for those receiving MMT is also recommended to prevent relapses to heroin and other illicit substances.

Sexually transmitted and blood-borne infection risk reduction with methadone and buprenorphine/naloxone among people with prescription-type opioid use disorder: Findings from a Canadian pragmatic randomized trial.

INTRODUCTION: People who use drugs are disproportionally affected by sexually transmitted and blood-borne infections (STBBIs). While the benefits of methadone in reducing injecting-risk behaviours are well documented, less is known on its impacts on sexual-related risks, as well as its comparative effectiveness to buprenorphine/naloxone, particularly in the context of highly potent opioids. The aim of this study was to estimate the relative effects of buprenorphine/naloxone and methadone on injecting and STBBI risks among people with prescription-type opioid use disorder (POUD). METHODS: Secondary analysis of a pan-Canadian pragmatic 24-week randomized clinical trial comparing methadone and buprenorphine/naloxone models of care among 272 people with POUD (including licit or illicit opioid analgesics, fentanyl). The Risk Behaviour Survey was used to collect injecting and sexual risks at baseline, and weeks 12 and 24. RESULTS: In total, 210 participants initiated treatment (103 buprenorphine/naloxone and 107 methadone). At baseline, 113/205 (55.1%) participants reported recently injecting drugs, 37/209 (17.7%) unsafe injection practices and 67/162 (41.4%) high-risk sex. Both methadone and buprenorphine/naloxone were associated with reductions in the prevalence of injection drug use and high-risk sex at weeks 12 and 24 with no interactions between treatment arm and time. CONCLUSION: Methadone and buprenorphine/naloxone were similarly effective in reducing injecting and sexual risk behaviours among people with POUD. CLINICAL TRIALS REGISTRATION: clinicaltrials.gov NCT03033732.

Experiences of Aging with Opioid Use Disorder and Comorbidity in Opioid Treatment Programs: A Qualitative Analysis.

BACKGROUND: The number of older adults entering opioid treatment programs (OTPs) to treat opioid use disorder (OUD) is increasing. However, the lived experiences of aging in OTPs have not been examined. OBJECTIVE: To explore the aging experience with OUD and barriers to medical care for older adults who receive care in OTPs. DESIGN: From November 2021 to July 2022, we conducted 1-to-1, semi-structured qualitative interviews in English and Spanish, audio-recorded, transcribed, systematically coded, and analyzed to identify key themes regarding the challenges of aging with OUD and managing chronic diseases. PARTICIPANTS: Thirty-six adults aged ≥ 55 enrolled in OTPs in San Diego, California. APPROACH: A descriptive qualitative approach was used. Major themes and subthemes were identified through thematic analysis until thematic saturation was reached. KEY RESULTS: All participants were on methadone and had a mean age of 63.4 (SD 5.1) years; 11 (30.6%) identified as female, 14 (39%) as Hispanic/Latino, and 11 (36%) as Black, with a mean duration of methadone treatment of 5.6 years. Chronic diseases were common, with 21 (58.3%) reporting hypertension, 9 (25%) reporting untreated hepatitis C, and 32 (88.9%) having ≥ 2 chronic diseases. Three major themes emerged: (1) avoidance of medical care due to multiple intersectional stigmas, including those related to drug use, substance use disorder (SUD) treatment, ageism, and housing insecurity; (2) increasing isolation with aging and loss of family and peer groups; (3) the urgent need for integrating medical and aging-focused care with OUD treatment in the setting of increasing health and functional challenges. CONCLUSIONS: Older adults with OUD reported increasing social isolation and declining health while experiencing multilevel stigma and discrimination. The US healthcare system must transform to deliver age-friendly care that integrates evidence-based geriatric models of care incorporated with substance use disorder treatment and addresses the intersectional stigma this population has experienced in healthcare settings.

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.

In-Hospital Methadone Enrollment: a Novel Program to Facilitate Linkage from the Hospital to the Opioid Treatment Program for Vulnerable Patients with Opioid Use Disorder.

INTRODUCTION: Methadone ameliorates opioid withdrawal among hospitalized patients with opioid use disorder (OUD). To continue methadone after hospital discharge, patients must enroll in an opioid treatment program (OTP) per federal regulations. Uncontrolled opioid withdrawal is a barrier to linkage from hospital to OTP. AIM: Describe a federally compliant In-Hospital Methadone Enrollment Team (IN-MEET) that enrolls hospitalized patients with OUD into an OTP with facilitated hospital to OTP linkage. SETTING: Seven hundred-bed university hospital in Aurora, CO. PROGRAM DESCRIPTION: A physician dually affiliated with a hospital's addiction consultation service and a community OTP completes an in-hospital, face-to-face medical assessment required by federal law and titrates methadone to comfort. An OTP-affiliated nurse with hospital privileges completes a psychosocial evaluation and provides case management by arranging transportation and providing weekly telephone check-ins. PROGRAM EVALUATION METRICS: IN-MEET enrollments completed, hospital to OTP linkage, and descriptive characteristics of patients who completed IN-MEET enrollments compared to patients who completed community OTP enrollments. RESULTS: Between April 2019 and April 2023, our team completed 165 IN-MEET enrollments. Among a subset of 73 IN-MEET patients, 56 (76.7%) presented to the OTP following hospital discharge. Compared to community OTP enrolled patients (n = 1687), a higher percentage of IN-MEET patients were older (39.7 years, standard deviation [SD] 11.2 years vs. 36.1 years, SD 10.6 years) and were unhoused (n = 43, 58.9% vs. n = 199, 11.8%). Compared to community OTP enrolled patients, a higher percentage of IN-MEET patients reported heroin or fentanyl as their primary substance (n = 53, 72.6% vs. n = 677, 40.1%), reported methamphetamine as their secondary substance (n = 27, 37.0% vs. n = 380, 22.5%), and reported they injected their primary substance (n = 46, 63.0% vs. n = 478, 28.3%). CONCLUSION: IN-MEET facilitates hospital to OTP linkage among a vulnerable population. This model has the potential to improve methadone access for hospitalized patients who may not otherwise seek out treatment.

A Climate of Stigma, Uncertainty, and Distrust: Stakeholder Perception of Barriers to SNF Placement for Patients with Opioid Use Disorder Treated with Methadone.

BACKGROUND: Patients with opioid use disorder (OUD), especially those treated with methadone, face significant challenges to placement in a skilled nursing facility (SNF). Efforts to address this via legal actions have not resulted in improved access. OBJECTIVE: To understand regulatory and non-regulatory factors that impact SNF placement of patients with OUD treated with methadone. DESIGN: Observational qualitative study. PARTICIPANTS: Stakeholders in the hospital-to-SNF referral process as well as those with specific expertise related to OUD. APPROACH: Open-ended, semi-structured interviews. RESULTS: Interviews with 15 participants identified three key themes that function together in addition to logistic and financial barriers: (1) stigma and perception of risk, (2) uncertain regulatory environment, and (3) distrust between responsible entities. Fundamentally, many SNFs do not feel they can provide necessary care related to OUD and methadone. They tend to be disinclined to care for patients with OUD and express concerns about perceived risks such as overdose, violence, or discomfort to other residents. SNFs are also very motivated to avoid regulatory citations and fines related to OUD or methadone. Since confusion and misinformation about relevant policies and procedures is common, many opt to decline these patients. Compounding these challenges, entities responsible for coordinating care demonstrate poor communication and lack of transparency with each other. Referral and declination information sent between hospitals and SNFs is often considered to be incomplete or incorrect, and many hospitals have stopped referring patients with OUD treated with methadone to SNFs altogether. Regulatory bodies are often feared by healthcare providers and administrators and interaction is avoided. Finally, legal oversight representatives report that they do not receive sufficient information to properly investigate concerns. CONCLUSION: This study identifies the climate of stigma, uncertainty, and distrust between responsible entities that stymies improvement efforts. Creation of meaningful reform must address each of these areas.

The relationship of pain intensity and opioid craving with delayed methadone dose: A preliminary study of individuals with opioid use disorder.

AIMS: Despite a strong theoretical link between opioid craving and pain, little is known about the temporal relationship between pain and craving and the acute experience of pain in the context of methadone treatment. Using a cross-over design, the current study evaluated the time course of pain and craving and objective experience of pain as a function of the last methadone dose. METHODS: Participants (n = 20) presented for the study in the morning and either received methadone dose as scheduled or delayed dose until the afternoon. During the 4-h study visit, participants completed a series of tasks, including repeated assessment of pain and craving at 0, +40, +70, +130, +160 and +240 min and a cold pressor test (CPT) at +15 and +220 min. RESULTS: Separate mixed model results demonstrated no effect of dosing condition on craving; however, there was a significant dosing condition by time interaction (F(5,209) = 3.38, P = .006) such that pain increased over time in the delayed methadone condition but decreased in time in the scheduled methadone condition. A mixed model predicting self-reported pain revealed a three-way interaction between dosing condition, craving and time (F(5,197) = 2.39, P = .039) explained by a positive association between craving and pain at each time point (except 240 min) in delayed condition (P-range = .004-.0001). A separate mixed model on CPT data indicated a significant condition by time interaction such that pain threshold decreased in the delayed, but not scheduled, condition (F(1,57) = 4.01, P = .050). CONCLUSIONS: These preliminary findings highlight the potential for increased risks after even a short delay in receiving a methadone dose.

CYP2B6 and ABCB1 genotypes predict methadone plasma exposure among patients on maintenance therapy against opioid addictions in Tanzania.

AIMS: Methadone maintenance therapy (MMT) exhibits significant variability in pharmacokinetics and clinical response, partly due to genetic variations. However, data from sub-Saharan African populations are lacking. We examined plasma methadone variability and pharmacogenetic influences among opioid-addicted Tanzanian patients. METHODS: Patients attending MMT clinics (n = 119) in Tanzania were genotyped for common functional variants of the CYP3A4, CYP3A5, CYP2A6, CYP2B6, CYP2C19, CYP2D6, ABCB1, UGT2B7 and SLCO1B1 genotypes. Trough plasma concentrations of total methadone, S-methadone (S-MTD) and R-methadone (R-MTD), with their respective metabolites, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The methadone-to-EDDP metabolic ratio (MMR) was used to categorize the phenotype. RESULTS: The proportions of MMR-predicted ultrarapid, extensive, intermediate and slow methadone metabolizer phenotypes were 2.5%, 58.2%, 23.7% and 15.6%, respectively. CYP2B6 genotype significantly correlated with S-methadone (P = .006), total methadone (P = .03), and dose-normalized methadone plasma concentrations (P = .001). Metabolic ratios of R-methadone (R-MTD/R-EDDP), S-methadone (S-MTD/S-EDDP), and total methadone (MMR) were significantly higher among patients homozygous for defective variants (*6 or *18) than heterozygous or CYP2B6*1/*1 genotypes (P < .001). The metabolic ratio for S-MTD and total methadone was significantly higher among ABCB1c.3435T/T than in the C/C genotype. No significant effect of CYP2D6, CYP2C19, CYP3A4, CYP3A5, CYP2A6, UGT2B7 and SLCO1B1 genotypes on S-methadone, R-methadone, or total methadone was observed. CONCLUSIONS: Approximately one in six opioid-addicted Tanzanian patients are methadone slow metabolizers, influenced by genetic factors. Both the CYP2B6 and ABCB1 genotypes are strong predictors of methadone metabolic capacity and plasma exposure. Further investigation is needed to determine their predictive value for methadone treatment outcomes and to develop genotype-based dosing algorithms for safe and effective therapy.

Satisfaction Amongst Drug-dependent Population with Methadone Maintenance Treatment Services, A Comparison between Public and Private Clinics: Implications for Private Sector Engagement in the Delivery of Methadone Maintenance Programs Across Vietnam.

In Vietnam, the public sector has largely been responsible for delivering methadone maintenance treatment (MMT) services. However, with foreign aid anticipated to decline in the coming years, the involvement of the private sector in delivering MMT services is critical to ensure the continued sustainability of MMT programs across Vietnam. This study aims to evaluate patient satisfaction and identify correlated factors among Vietnamese drug users undergoing MMT in both public and private methadone clinics. A cross-sectional study was conducted in one private and two public methadone facilities in Nam Dinh, a province in the North of Vietnam. A convenience sampling technique was applied to recruit 395 participants. Data was collected through 20-minute face-to-face interviews using a structured questionnaire. Multivariate Tobit regression was utilized to measure associated factors with patient satisfaction. Results showed that patients were highly satisfied with MMT services in both public and private; however, they expected a higher degree of comprehensive care services. Compared with public facilities, the satisfaction level of patients in private facilities was significantly lower in the following aspects: health administration and professional capacity of health workers. However, there were insignificant differences in regard to infrastructure, equipment, and availability of medical services resources, supporting a promising role of the private sector in supporting the expansion of the MMT programs in Vietnam. Integrating MMT with other physical and mental healthcare services, along with strategies for improving administrative procedures and health workers' capacity in private clinics, are critical implications of this study.

Does cannabis use substitute for opioids? A preliminary exploratory survey in opioid maintenance patients.

Various studies showed that people with substance use disorder use cannabis to reduce withdrawal or dose of their main drug. Using a questionnaire about their cannabis use, 118 participants in an opioid maintenance treatment (OMT) in Germany were examined regarding this strategy. 60% reported to use cannabis. Of those, 72% were using cannabis in the suggested way. Cannabis was used to substitute for, e.g., heroin (44.8%) and benzodiazepines (16.4%). We also asked for an estimation of how good cannabis was able to substitute for several substances (in German school grades (1 till 6)); heroin average grade: 2.6 ± 1.49. Besides that we asked about the idea of cannabis as "self-medication", e.g., to reduce pain (47%) and about negative consequences from cannabis use. Our results suggest to consider the use of cannabis by patients in OMT rather as a harm reduction strategy to reduce the intake of more dangerous drugs.

DRD2 TaqIA polymorphism-related functional connectivity between anterior insula and dorsolateral prefrontal cortex predicts the retention time in heroin-dependent individuals under methadone maintenance treatment.

BACKGROUND: Dopamine receptor D2 (DRD2) TaqIA polymorphism has an influence on addiction treatment response and prognosis by mediating brain dopaminergic system efficacy. Insula is crucial for conscious urges to take drugs and maintain drug use. However, it remains unclear about the contribution of DRD2 TaqIA polymorphism to the regulation of insular on addiction behavioral and its relation with the therapeutic effect of methadone maintenance treatment (MMT). METHODS: 57 male former heroin dependents receiving stable MMT and 49 matched male healthy controls (HC) were enrolled. Salivary genotyping for DRD2 TaqA1 and A2 alleles, brain resting-state functional MRI scan and a 24-month follow-up for collecting illegal-drug-use information was conducted and followed by clustering of functional connectivity (FC) patterns of HC insula, insula subregion parcellation of MMT patients, comparing the whole brain FC maps between the A1 carriers and non-carriers and analyzing the correlation between the genotype-related FC of insula sub-regions with the retention time in MMT patients by Cox regression. RESULTS: Two insula subregions were identified: the anterior insula (AI) and the posterior insula (PI) subregion. The A1 carriers had a reduced FC between the left AI and the right dorsolateral prefrontal cortex (dlPFC) relative to no carriers. And this reduced FC was a poor prognostic factor for the retention time in MMT patients. CONCLUSION: DRD2 TaqIA polymorphism affects the retention time in heroin-dependent individuals under MMT by mediating the functional connectivity strength between left AI and right dlPFC, and the two brain regions are promising therapeutic targets for individualized treatment.

Opioid Use and the Risk of Ventricular Arrhythmias: A Systematic Review and Meta-Analysis.

BACKGROUND: The association between opioid use and the risk of ventricular arrhythmias (VA) is poorly understood. AIMS: The objective of this study was to synthesize the evidence on the risk of VA associated with opioid use. MATERIALS & METHODS: We systematically searched the Cochrane Library, Embase, MEDLINE, and CINAHL databases in July 2022. Risk of bias was assessed using the Cochrane risk for bias tool for randomized controlled trials (RCTs) and ROBINS-I for observational studies. Certainty of evidence was assessed using GRADE. RESULTS: We included 15 studies (12 observational, 2 post hoc analyses of RCTs, 1 RCT). Most studies focused on opioid use for maintenance therapy (n = 9), comparing methadone to buprenorphine (n = 13), and reported QTc prolongation (n = 13). Six observational studies had a critical risk of bias, and one RCT was at high risk of bias. Two studies could not be included in the meta-analysis as they reported a different outcome and studied an opioid antagonist. Meta-analysis of 13 studies indicated that the use of methadone was associated with an increased risk of VA compared to the use of buprenorphine, morphine, placebo, or levacetylmethadol (risk ratio [RR], 2.39; 95% CI, 1.31-4.35; I2 = 60%). The pooled estimate varied greatly between observational studies (RR, 2.12; 95% CI, 1.15-3.91; I2 = 62%) and RCTs (RR, 14.09; 95% CI, 1.52-130.61; I2 = 0%), but both indicated an increased risk. CONCLUSION: In this systematic review and meta-analysis, we found that methadone use is associated with more than twice the risk of VA compared to comparators. However, our findings should be interpreted cautiously given the limited quality of the available evidence.

Methadone versus other opioids for refractory malignant bone pain: a pilot randomised controlled study.

PURPOSE: Refractory cancer-induced bone pain (CIBP) affects a patient's functional capacity and quality of life, but there is limited evidence to guide opioid choice. We assessed the feasibility, tolerability and possible efficacy of methadone rotation (MR) compared to other opioid rotations (OOR) in this cohort. METHODS: Adults with CIBP and worst pain intensity ≥ 4/10 and/or opioid toxicity graded ≥ 2 on the Common Terminology Criteria for Adverse Events were randomised 1:1 to methadone or another opioid rotation. Standardised assessment tools were used at pre-defined study time points up to 14 days. RESULTS: Of 51 eligible participants, 38 (74.5%) consented, and 29 (76.3%, MR: 14, OOR: 15) completed the fourteen days follow-up post-opioid rotation. Both groups displayed significant reduction in average (MR: d = - 1.2, p = 0.003, OOR: d = - 0.8, p = 0.015) and worst pain (MR: d = - 0.9, p = 0.042, OOR: d = - 0.6, p = 0.048) and total pain interference score (MR: d = - 1.1, p = 0.042, OOR: d = - 0.7, p = 0.007). Oral morphine equivalent daily dose was reduced significantly in MR compared to the OOR group (d = - 0.8, p = 0.05). The incidence of opioid-related adverse events following MR was unchanged but lower in the OOR group (d = 0.9, 95% CI 0.1,1.7, p = 0.022). There were no within-group or between-group differences in satisfaction with analgesia at the end of the study. CONCLUSION: This pilot study demonstrated that MR and OOR in patients with refractory CIBP are feasible, safe and acceptable to patients. Appropriately powered multi-centre randomised controlled studies are needed to confirm the efficacy of MR and OOR in this cohort. TRIAL REGISTRATION: ACTRN12621000141842 registered 11 February 2021.

Low-dose methadone added to another opioid for cancer pain: a multicentre prospective study.

CONTEXT: The use of methadone for cancer pain management is gaining wider acceptance. However, switching to methadone treatment can still pose challenges. Consequently, there is ongoing development of its use in low doses in combination with other opioids, despite a lack of clinical evidence regarding its efficacy and safety. OBJECTIVES: This study aimed to evaluate the efficacy and tolerability of low-dose methadone in combination with another opioid in patients with moderate-to-severe cancer-related pain in a clinical setting. PATIENTS AND METHODS: This was a prospective, open-label study conducted in 19 pain and/or palliative care centres treating patients with cancer-related pain. Pain intensity, patients' global impression of change, and adverse effects were assessed on day 7 and day 14. The main outcome measure was the proportion of responders. RESULTS: The study included 92 patients. The daily dose of methadone was 3 [3-6] mg at baseline, 9 [4-10] mg on day 7 and 10 [6-15] mg on day 14. The NRS pain ratings significantly decreased from 7 [6-8] at baseline to 5 [3-6] on visit 2 (p < .0001) and 4 [3-6] on visit 3 (p < .0001). Similarly, the VRS pain ratings decreased from 3 [3-3] at baseline to 2 [2-3] on visit 2 (p = 0.026) and 2 [1-3] (p < 0.001) on visit 3. At Visits 1 and 2, half of the patients were considered Responders. Of those responders, 73.5% were High-Responders at Visit 1 and 58.7% were High-Responders at Visit 2. No adverse events related to the risk of QT prolongation, overdose, or drug interactions were reported. CONCLUSION: For patients experiencing moderate to severe cancer-related pain despite initial opioid treatment, our study found that low-dose methadone, when used in combination with another opioid, was both safe and effective. This supports the use of methadone as an adjunct to opioid-based treatment for cancer pain.

Maternal opioid use during pregnancy and the risk of neonatal opioid withdrawal syndrome in the offspring.

INTRODUCTION: Neonatal opioid withdrawal syndrome (NOWS) is caused by sudden cessation from in utero exposure to opioids. The indications for opioid use during pregnancy are diverse including medication for opioid use disorder and analgesia. The opioid dose typically depends on the indication, with higher doses used for medication for opioid use disorder and lower doses used for analgesia. The aim of this study was to investigate the relationship between maternal opioid dose during pregnancy and the risk of NOWS. MATERIAL AND METHODS: We conducted a historical multicenter cohort study of neonates prenatally exposed to opioids in Eastern Denmark during a six-year period from 2013 to 2018. The data was extracted from reviewing the individual's medical record(s), which were identified through a search of the Danish National Patient Register. Four groups (quartiles) according to maternal opioid dose during the last four weeks prior to delivery were compared. Unadjusted and adjusted logistic regression analyses were conducted to examine the risk of NOWS while controlling for relevant covariates. RESULTS: A total of 130 in utero opioid exposed neonates were included. The majority of the pregnant patients (88%) were treated with opioids for analgesic purposes. Overall, 52% of neonates developed NOWS. The cumulative incidence of NOWS was 21%, 28%, 67% and 91% at maternal average daily dose of morphine milligram equivalent during the last four weeks prior to delivery of 0.7-14 (group I), 14.3-38.6 (group II), 40-90 (group III) and 90.9-1440 (group IV), respectively. Compared to group I the adjusted odds (aOR) of NOWS increased significantly in group III (aOR 10.6 [2.9-39.1]) and group IV (aOR 37.8 [7.6-188.2]) but not in group II (aOR 1.5 [0.4-5.2]). No cases of NOWS were reported at maternal dose less than an average daily dose of five morphine milligram equivalent during the last four weeks prior to delivery. No significant changes in the incidence of NOWS were observed between 2013 and 2018. CONCLUSIONS: The odds of neonatal opioid withdrawal syndrome increased significantly as the maternal average daily dose of morphine milligram equivalent during the last four weeks prior to delivery surpassed 40.

Combined in vivo metabolic effects of quetiapine and methadone in brain and blood of rats.

Changes in pharmacokinetics and endogenous metabolites may underlie additive biological effects of concomitant use of antipsychotics and opioids. In this study, we employed untargeted metabolomics analysis and targeted analysis to examine the changes in drug metabolites and endogenous metabolites in the prefrontal cortex (PFC), midbrain, and blood of rats following acute co-administration of quetiapine and methadone. Rats were divided into four groups and received cumulative increasing doses of quetiapine (QTP), methadone (MTD), quetiapine + methadone (QTP + MTD), or vehicle (control). All samples were analyzed using liquid chromatography-mass spectrometry (LC-MS). Our findings revealed increased levels of the quetiapine metabolites: Norquetiapine, O-dealkylquetiapine, 7-hydroxyquetiapine, and quetiapine sulfoxide, in the blood and brain when methadone was present. Our study also demonstrated a decrease in methadone and its metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in the rat brain when quetiapine was present. Despite these findings, there were only small differences in the levels of 225-296 measured endogenous metabolites due to co-administration compared to single administrations. For example, N-methylglutamic acid, glutaric acid, p-hydroxyphenyllactic acid, and corticosterone levels were significantly decreased in the brain of rats treated with both compounds. Accumulation of serotonin in the midbrain was additionally observed in the MTD group, but not in the QTP + MTD group. In conclusion, this study in rats suggests a few but important additive metabolic effects when quetiapine and methadone are co-administered.

Associations Between Buprenorphine\Naloxone and Methadone Treatment and non-Opioid Substance Use in Prescription-Type Opioid Use Disorder: Secondary Analyses From the OPTIMA Study: Associations entre le traitement avec la buprénorphine/naloxone et avec la méthadone et l'utilisation de substances non opioïdes dans le trouble lié à l'usage d'opioïdes de type sur ordonnance : analyses secondaires de l'étude OPTIMA.

OBJECTIVES: There is limited evidence on how opioid agonist treatment (OAT) may affect psychoactive non-opioid substance use in prescription-type opioid use disorder (POUD) and whether this effect might explain OAT outcomes. We aimed to assess the effect of methadone on non-opioid substance use compared to buprenorphine/naloxone (BUP/NX), to explore whether non-opioid substance use is associated with opioid use and retention in treatment, and to test non-opioid use as a moderator of associations between methadone with retention in OAT and opioid use compared to BUP/NX. METHODS: This is a secondary analysis of data from the OPTIMA trial, an open-label, pragmatic, parallel, two-arm, pan-Canadian, multicentre, randomized-controlled trial to compare standard methadone model of care and flexible take-home dosing BUP/NX for POUD treatment. We studied the effect of methadone and BUP/NX on non-opioid substance use evaluated by urine drug screen (UDS) and by classes of non-opioid substances (i.e., tetrahydrocannabinol [THC], benzodiazepines, stimulants) (weeks 2-24) using adjusted generalized estimation equation (GEE). We studied the association between non-opioid substance-positive UDS and opioid-positive UDS and retention in treatment, using adjusted GEE and logistic regressions. RESULTS: Overall, methadone was not associated with non-opioid substance-positive UDS compared to BUP/NX (OR: 0.78; 95%CI, 0.41 to 1.48). When non-opioid substances were studied separately, methadone was associated with lower odds of benzodiazepine-positive UDS (OR: 0.63; 95% CI: 0.40 to 0.98) and THC-positive UDS (OR: 0.47; 95% CI: 0.28 to 0.77), but not with different odds of stimulant-positive UDS (OR: 1.29; 95% CI: 0.78 to 2.16) compared to BUP/NX. Substance-positive UDS, overall and separate classes, were not associated with opioid-positive UDS or retention in treatment. CONCLUSION: Methadone did not show a significant effect on overall non-opioid substance use in POUD compared to BUP/NX treatment but was associated with lower odds of benzodiazepine and THC use in particular. Non-opioid substance use did not predict OAT outcomes. Further research is needed to ascertain whether specific patterns of polysubstance use (quantity and frequency) may affect treatment outcomes.

The Association Between Self-Reported Anxiety and Retention in Opioid Agonist Therapy: Findings From a Canadian Pragmatic Trial.

BACKGROUND: Prescription-type opioid use disorder (POUD) is often accompanied by comorbid anxiety, yet the impact of anxiety on retention in opioid agonist therapy (OAT) is unclear. Therefore, this study investigated whether baseline anxiety severity affects retention in OAT and whether this effect differs by OAT type (methadone maintenance therapy (MMT) vs. buprenorphine/naloxone (BNX)). METHODS: This secondary analysis used data from a pan-Canadian randomized trial comparing flexible take-home dosing BNX and standard supervised MMT for 24 weeks. The study included 268 adults with POUD. Baseline anxiety was assessed using the Beck Anxiety Inventory (BAI), with BAI ≥ 16 indicating moderate-to-severe anxiety. The primary outcomes were retention in assigned and any OAT at week 24. In addition, the impact of anxiety severity on retention was examined, and assigned OAT was considered an effect modifier. RESULTS: Of the participants, 176 (65%) reported moderate-to-severe baseline anxiety. In adjusted analyses, there was no significant difference in retention between those with BAI ≥ 16 and those with BAI < 16 assigned (29% vs. 28%; odds ratio (OR) = 2.03, 95% confidence interval (CI) = 0.94-4.40; P = 0.07) or any OAT (35% vs. 34%; OR = 1.57, 95% CI = 0.77-3.21; P = 0.21). In addition, there was no significant effect modification by OAT type for retention in assigned (P = 0.41) or any OAT (P = 0.71). In adjusted analyses, greater retention in treatment was associated with BNX (vs. MMT), male gender identity (vs. female, transgender, or other), enrolment in the Quebec study site (vs. other sites), and absence of a positive urine drug screen for stimulants at baseline. CONCLUSIONS: Baseline anxiety severity did not significantly impact retention in OAT for adults with POUD, and there was no significant effect modification by OAT type. However, the overall retention rates were low, highlighting the need to develop new strategies to minimize the risk of attrition from treatment. CLINICAL TRIAL REGISTRATION: This study was registered in ClinicalTrials.gov (NCT03033732).

Methadone and Buprenorphine in the Perioperative Setting: A Review of the Literature.

PURPOSE OF REVIEW: The purpose of this review is to highlight the most recent literature and guidelines regarding perioperative methadone and buprenorphine use. RECENT FINDINGS: Surgical patients taking methadone and buprenorphine are being encountered more frequently in the perioperative period, and providers are becoming more familiar with their pharmacologic properties, benefits as well as precautions. Recommendations pertaining to buprenorphine therapy in the perioperative settings have changed in recent years, owing to more clinical and basic science research. In addition to their use in chronic pain and opioid use disorders, they can also be initiated for acute postoperative pain indications, in select patients and situations. Methadone and buprenorphine are being more commonly prescribed for pain management and opioid use disorder, and their continuation during the perioperative period is generally recommended, to reduce the risk of opioid withdrawal, relapse, or inadequately controlled pain. Additionally, both may be initiated safely and effectively for acute pain management during and after the operating room period.