Mediating effect of craving on the impact of buprenorphine/naloxone and methadone treatment on opioid use: Results from a randomized controlled trial.

BACKGROUND: The relationship between opioid craving and opioid use is unclear. We sought to determine to what extent craving mediated the relationship between opioid agonist therapy and changes in opioid use. METHODS: Data came from a pragmatic, 24-week, pan-Canadian, multi-centric, open-label, randomized controlled trial comparing flexible buprenorphine/naloxone take-home doses to standard supervised methadone models of care for the treatment of prescription-type opioid use disorder. Participants were randomly allocated to buprenorphine/naloxone or methadone models of care. 270 people with prescription-type opioid use disorder were included in analyses. There were 93 women (34.4%) and 2 transgender (0.7%) participants. Most participants were white (67.4%), 45.9% reported unstable living conditions, and 44.8% had psychiatric comorbidities. Generalized linear mixed models followed by mediation analysis estimated the direct effect of treatment group on Timeline Followback-reported next-week opioid use and the indirect effect through past 24-hour opioid craving measured using the Brief Substance Craving Scale at week 2, 6, 10, 14, 18 and 22. RESULTS: Upon mediation analysis, the average direct effect of treatment on opioid use was 0.465 (95 % CI = 0.183 to 0.751, p < 0.001). The average causal mediated effect was 0.144 (95 % CI = 0.021 to 0.110; p < 0.001). Craving accounted for 23.6 % of the effect of treatment on opioid use (p < 0.001). CONCLUSIONS: Past 24-hour craving was associated with increased next-week opioid use; however, craving only partially mediated the effect of buprenorphine/naloxone and methadone on next-week opioid use. Research is needed to develop a comprehensive understanding of factors mediating opioid use during opioid agonist therapy.

Impact of Depressive Symptom Severity on Buprenorphine/Naloxone and Methadone Outcomes in People With Prescription-Type Opioid Use Disorder: Results From a Pragmatic Randomized Controlled Trial.

OBJECTIVE: To evaluate the impact of depressive symptom severity on opioid use and treatment retention in individuals with prescription-type opioid use disorder (POUD). METHOD: We analyzed data from a multi-centric, pragmatic, open-label, randomized controlled trial comparing buprenorphine/naloxone to methadone models of care in 272 individuals with POUD. Opioid use was self-reported every two weeks for 24 weeks using the Timeline Followback. Depressive symptom severity was self-reported with the Beck Depression Inventory at baseline, week 12 and week 24. RESULTS: Baseline depressive symptom severity was not associated with opioid use nor treatment retention. At week 12, moderate depressive symptoms were associated with greater opioid use while mild to severe depressive symptoms were associated with lowered treatment retention. At week 24, moderate depressive symptoms were associated with greater opioid use. CONCLUSIONS: Ongoing depressive symptoms lead to poorer outcomes in POUD. Clinicians are encouraged to use integrative approaches to optimize treatment outcomes. This study was registered in ClinicalTrials.gov (NCT03033732) on January 27th, 2017, prior to participants enrollment.

Prescription psychostimulants for the treatment of amphetamine-type stimulant use disorder: A systematic review and meta-analysis of randomized placebo-controlled trials.

BACKGROUND AND AIMS: There is currently no standard of care for pharmacological treatment of amphetamine-type stimulant (ATS) use disorder (ATSUD). This systematic review with meta-analysis (PROSPERO CRD42022354492) aimed to pool results from randomized placebo-controlled trials (RCTs) to evaluate efficacy and safety of prescription psychostimulants (PPs) for ATSUD. METHODS: Major indexing sources and trial registries were searched to include records published before 29 August 2022. Eligible studies were RCTs evaluating efficacy and safety of PPs for ATSUD. Risk of bias (RoB) was assessed using the Cochrane RoB 2 tool. Risk ratio (RR) and risk difference were calculated for random-effect meta-analysis of dichotomous variables. Mean difference and standardized mean difference (SMD) were calculated for random-effect meta-analysis of continuous variables. RESULTS: Ten RCTs (n = 561 participants) were included in the meta-analysis. Trials studied methylphenidate (n = 7), with daily doses of 54-180 mg, and dextroamphetamine (n = 3), with daily doses of 60-110 mg, for 2-24 weeks. PPs significantly decreased end-point craving [SMD  -0.29; 95% confidence interval (CI) = -0.55, -0.03], while such a decrease did not reach statistical significance for ATS use, as evaluated by urine analysis (UA) (RR = 0.93; 95% CI = 0.85-1.01). No effect was observed for self-reported ATS use, retention in treatment, dropout following adverse events, early-stage craving, withdrawal and depressive symptoms. In a sensitivity analysis, treatment was associated with a significant reduction in UA positive for ATS (RR = 0.89; 95% CI = 0.79-0.99) after removing studies with a high risk of bias. In subgroup analyses, methylphenidate and high doses of PPs were negatively associated with ATS use by UA, while higher doses of PPs and treatment duration (≥ 20 weeks) were positively associated with longer retention. CONCLUSIONS: Among individuals with amphetamine-type stimulant use disorder, treatment with prescription psychostimulants may decrease ATS use and craving. While effect size is limited, it may increase with a higher dosage of medications.

Associations of methadone and buprenorphine-naloxone doses with unregulated opioid use, treatment retention, and adverse events in prescription-type opioid use disorders: Exploratory analyses of the OPTIMA study.

BACKGROUND AND OBJECTIVES: Buprenorphine/naloxone (BUP-NX) and methadone are used to treat opioid use disorder (OUD), yet there is insufficient evidence on the impact of doses on interventions' effectiveness and safety when treating OUD attributable to other opioids than heroin. METHODS: We explored associations between methadone and BUP-NX doses and treatment outcomes using data from OPTIMA, a 24-week, pragmatic, open-label, multicenter, pan-Canadian, randomized controlled, two-arm parallel trial with participants (N = 272) with OUD who primarily use opioids other than heroin. Participants were randomized to receive flexible take-home BUP-NX (n = 138) or standard supervised methadone treatment (n = 134). We examined associations between highest BUP-NX and methadone doses, and (1) percentage of opioid-positive urine drug screens (UDS); (2) retention in the assigned treatment; and (3) adverse events (AEs). RESULTS: The mean (SD) highest BUP-NX and methadone dose were 17.31 mg/day (8.59) and 67.70 mg/day (34.70). BUP-NX and methadone doses were not associated with opioid-positive UDS percentages or AEs. Methadone dose was associated with higher retention in treatment (odds ratio [OR]: 1.025; 95% confidence interval [CI]: 1.010; 1.041), while BUP-NX dose was not (OR: 1.055; 95% CI: 0.990; 1.124). Higher methadone doses (70-110 mg/day) offered higher odds of treatment retention. DISCUSSION AND CONCLUSION: Methadone dose was associated with higher retention, which may be related to its full µ-opioid receptor agonism. Future research should notably ascertain the effect of pace of titration on a wide range of outcomes. SCIENTIFIC SIGNIFICANCE: Our results extend previous findings of high doses of methadone increasing retention to be applied in our population using opioids other than heroin, including highly potent opioids.

Differential effect of cannabis use on opioid agonist treatment outcomes: Exploratory analyses from the OPTIMA study.

INTRODUCTION: Conflictual evidence exists regarding the effects of cannabis use on the outcomes of opioid agonist therapy (OAT). In this exploratory analysis, we examined the effect of recent cannabis use on opioid use, craving, and withdrawal symptoms, in individuals participating in a trial comparing flexible buprenorphine/naloxone (BUP/NX) take-home dosing model to witnessed ingestion of methadone. METHODS: We analyzed data from a multi-centric, pragmatic, 24-week, open label, randomized controlled trial in individuals with prescription-type opioid use disorder (n = 272), randomly assigned to BUP/NX (n = 138) or methadone (n = 134). The study measured last week cannabis and opioid use via timeline-follow back, recorded at baseline and every two weeks during the study. Craving symptoms were measured using the Brief Substance Craving Scale at baseline, and weeks 2, 6, 10, 14, 18 and 22. The study measured opioid withdrawal symptoms via Clinical Opiate Withdrawal Scale at treatment initiation and weeks 2, 4, and 6. RESULTS: The mean maximum dose taken during the study was 17.3 mg/day (range = 0.5-32 mg/day) for BUP/NX group and 67.7 mg/day (range = 10-170 mg/day) in the methadone group. Repeated measures generalized linear mixed models demonstrated that cannabis use in the last week (mean of 2.3 days) was not significantly associated with last week opioid use (aß ± standard error (SE) = -0.06 ± 0.04; p = 0.15), craving (aß ± SE = -0.05 ± 0.08, p = 0.49), or withdrawal symptoms (aß ± SE = 0.09 ± 0.1, p = 0.36). Bayes factor (BF) for each of the tested models supported the null hypothesis (BF < 0.3). CONCLUSIONS: The current study did not demonstrate a statistically significant effect of cannabis use on outcomes of interest in the context of a pragmatic randomized-controlled trial. These findings replicated previous results reporting no effect of cannabis use on opioid-related outcomes.

Effects of Buprenorphine/Naloxone and Methadone on Depressive Symptoms in People with Prescription Opioid Use Disorder: A Pragmatic Randomised Controlled Trial.

OBJECTIVE: This study aimed to evaluate the effectiveness of flexible take-home dosing of buprenorphine/naloxone (BUP/NX) and methadone standard model of care in reducing depressive symptoms in people with prescription-type opioid use disorder (POUD). This trial also evaluated whether improvements in depressive symptoms were mediated by opioid use. METHODS: Analyzed data came from the OPTIMA study (clinicaltrials.gov identifier: NCT03033732), a pragmatic randomised controlled trial comparing flexible take-home dosing of BUP/NX and methadone standard model of care for reducing opioid use in people with POUD. A total of 272 participants were recruited in four Canadian provinces. Participants were randomised 1:1 to BUP/NX or methadone. After treatment induction, past two-week opioid use was measured using the Timeline Followback every two weeks for a total of 24 weeks. Depressive symptoms were measured with the Beck Depression Inventory at baseline, weeks 12 and 24. RESULTS: Both BUP/NX and methadone significantly reduced depressive symptoms at week 12 (aß ± SE = -3.167 ± 1.233; P < 0.001) and week 24 (aß ± SE = -7.280 ± 1.285; P < 0.001), with no interaction between type of treatment and time (P = 0.284). Improvements in depressive symptoms were only partially mediated by a reduction in opioid use (proportion mediated = 36.8%; 95% confidence interval = -1.158 to -0.070; P = 0.015). CONCLUSIONS: BUP/NX and methadone showed similar effectiveness in decreasing comorbid depressive symptoms in people with POUD. This effect was partially explained by a reduction in opioid use. As both treatments seem equally effective, clinicians are encouraged to tailor the selection of OAT to patients' needs and characteristics.

Efficacy of ketamine intervention to decrease alcohol use, cravings, and withdrawal symptoms in adults with problematic alcohol use or alcohol use disorder: A systematic review and comprehensive analysis of mechanism of actions.

BACKGROUND: Alcohol use disorder is highly prevalent and has important economical, societal, psychiatric, and medical consequences. All currently approved therapeutic approaches targeting alcohol dependence have relatively modest effects and high relapse rates. Recent evidence suggests that ketamine may be an effective intervention to treat alcohol use disorder and alcoholic withdrawal. This systematic review aimed to assess the current level of evidence for this intervention. METHODS: This systematic review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered on the international database of systematic reviews PROSPERO. Medline(Ovid), CINAHL Complete(EBSCOhost), PsycINFO(Ovid), EBM Reviews(Ovid), EMBASE(Ovid), and Google Scholar were searched for studies using ketamine to treat harmful alcohol use, craving, or withdrawal states in humans. Studies of any methodology that evaluated ketamine in isolation or combination with other interventions were included. The risk of bias was assessed using specific Cochrane critical appraisal tools. RESULTS: Of 1922 abstracts identified, 8 full-text articles were eligible for inclusion, yielding a total sample size of 634 participants. Five studies investigated the impact of ketamine on alcohol use and/or cravings and/or withdrawal in outpatient settings. Three studies looked at the effect of adding ketamine to conventional treatment of withdrawal symptoms in participants admitted to intensive care unit for severe alcohol withdrawal. Results on primary outcomes were mixed within and across trials. CONCLUSIONS: Despite promising results, the current evidence does not permit definitive conclusions about the efficacy of ketamine in alcohol use disorders or withdrawal. Future studies are warranted.

Buprenorphine/naloxone and methadone effectiveness for reducing craving in individuals with prescription opioid use disorder: Exploratory results from an open-label, pragmatic randomized controlled trial.

BACKGROUND: Craving reduction is an important target in the treatment of prescription-type opioid use disorder (POUD). In this exploratory analysis, we compared the effectiveness of BUP/NX flexible model of care relative to methadone for craving reduction in individuals with POUD. METHODS: We analyzed data from a multicentric, pragmatic, 24-week open-label randomized controlled trial conducted in participants with POUD (N = 272) who were randomly assigned to BUP/NX model of care with flexible take-home dosing (n = 138) or the standard model of care with closely supervised methadone (n = 134). Treatments were prescribed and administered according to local guidelines, in diverse clinical settings. Craving was measured using the Brief Substance Craving Scale at baseline, week 2, 6, 10, 14, 18 and 22. RESULTS: Cravings decreased in both treatment groups over 22 weeks (BUP/NX adjusted mean difference = -5.52, 95% CI = -6.91 to -4.13; methadone adjusted mean difference = -3.95, 95% CI = -5.28 to -2.63; p < 0.001), and were overall lower in the BUP/NX group (adjusted mean = 4.04, 95% CI = 3.43-4.64) than the methadone group (adjusted mean = 5.13, 95% CI = 4.51-5.74; p < 0.001). The time by treatment group interaction (favoring BUP/NX) was statistically significant at week 2 (adjusted mean difference = -1.58, 95% CI = -3.13 to -0.03; p = 0.041). CONCLUSIONS: Compared to the standard methadone model of care, flexible take-home dosing of BUP/NX was associated with lower craving in individuals with POUD. These findings can contribute to guiding shared decision-making regarding OAT treatment in this population.

Tau hyperphosphorylation induced by the anesthetic agent ketamine/xylazine involved the calmodulin-dependent protein kinase II.

Tau hyperphosphorylation is a major neuropathological hallmark of many neurodegenerative disorders such as Alzheimer's disease. Several anesthetics have been shown previously to induced marked tau hyperphosphorylation. Although the ketamine/xylazine mixture is one of the most commonly used anesthetic agents in animal research and veterinary practice, the effect of this anesthetic agent on tau phosphorylation still remains to be determined. Here, we found that ketamine-/xylazine-induced a rapid and robust hyperphosphorylation of tau in a dose-dependent manner under normothermic and hypothermic conditions in mice. When used together, ketamine and xylazine exerted a synergistic action on tau phosphorylation most strongly not only on epitopes S396 and S262, but also on other residues (T181, and S202/T205). We observed that activation of the calmodulin-dependent protein kinase II (CaMKII) is the major upstream molecular event leading to tau hyperphosphorylation following ketamine/xylazine anesthesia in mice. Moreover, we observed that intracerebroventricular injection of the selective CaMKII inhibitor KN93 attenuated tau hyperphosphorylation. Since ketamine/xylazine also had a marked impact on other key molecular signaling pathways involving the MAP/microtubule affinity-regulating kinase (MARK), extracellular signal-regulated kinase (ERK), and glycogen synthase kinase-3 (GSK3), our study calls for high caution and careful monitoring when using this anesthetic agent in laboratory animal settings across all fields of biological sciences in order to avoid artifactual results.