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.

Impacts of the COVID-19 pandemic on enrollment in medications for opioid use disorder (MOUD) in Vancouver, Canada: An interrupted time series analysis.

BACKGROUND: In anticipation of COVID-19 related disruptions to opioid use disorder (OUD) care, new provincial and federal guidance for the management of OUD and risk mitigation guidance (RMG) for prescription of pharmaceutical opioids were introduced in British Columbia, Canada, in March 2020. This study evaluated the combined impacts of the COVID-19 pandemic and counteracting OUD policies on enrollment in medications for OUD (MOUD). METHODS: Using data from three cohorts of people with presumed OUD in Vancouver, we conducted an interrupted time series analysis to estimate the combined effects impact of the COVID-19 pandemic and counteracting OUD policies on the prevalence of enrollment in MOUD overall, as well as in individual MOUDs (methadone, buprenorphine/naloxone, slow-release oral morphine) between November 2018 and November 2021, controlling for pre-existing trends. In sub-analysis we considered RMG opioids together with MOUD. RESULTS: We included 760 participants with presumed OUD. In the post-COVID-19 period, MOUD and slow-release oral morphine prevalence rates showed an estimated immediate increase in level (+7.6%, 95% CI: 0.6%, 14.6% and 1.8%, 95% CI: 0.3%, 3.3%, respectively), followed by a decline in the monthly trend (-0.8% per month, 95% CI: -1.4%, -0.2% and -0.2% per month, 95% CI: -0.4, -0.1, respectively). There were no significant changes in the prevalence trends of enrollment in methadone, buprenorphine/naloxone, or when RMG opioids were considered together with MOUD. CONCLUSIONS: Despite immediate improvements in MOUD enrollment in the post-COVID-19 period, this beneficial trend reversed over time. RMG opioids appeared to have provided additional benefits to sustain retention in OUD care.

Opioid agonist therapy switching among individuals with prescription-type opioid use disorder: Secondary analysis of a pragmatic randomized trial.

BACKGROUND: Engagement and retention in opioid agonist therapy (OAT) remains a challenge. This study evaluated the impact of initial randomized OAT allocation on subsequent switching among people with prescription-type opioid use disorder (POUD). METHODS: Secondary analysis of a 24-week Canadian multicenter, pragmatic, randomized trial conducted between 2017 and 2020 comparing flexible take-home buprenorphine/naloxone versus supervised methadone models of care for POUD. We used Cox Proportional Hazards modeling to assess for impact of treatment assignment on time to OAT switching, adjusting for important confounders. For clinical correlates, we analyzed data from baseline questionnaires on demographic, substance use, and health factors as well as urine drug screen. RESULTS: Of 272 randomized participants, 210 initiated OAT within 14 days per trial protocol, of whom 103 participants were randomized to buprenorphine/naloxone and 107 to methadone. Within 24-week follow-up, 41 (20.5%) of all participants switched OAT with 25 (24.3%, median 27 days, 88.4 per 100 person-years) and 16 participants (15.0%, median 53.5 days, 46.1 per 100 person-years) switching from buprenorphine/naloxone and methadone arms, respectively. In adjusted analysis, allocation to buprenorphine/naloxone was associated with significantly higher risk of switching (aHR = 2.31, 95% CI 1.22 - 4.38). CONCLUSIONS: OAT switching was common in this sample of individuals with POUD, with individuals randomly allocated to buprenorphine/naloxone being more than twice as likely to switch versus methadone. This may reflect a stepped care approach in OUD management. More research is needed to evaluate overall retention and outcomes with the different observed risks of switching between methadone and buprenorphine/naloxone.

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.

Prevalence and correlates of intentional substance use to reduce illicit opioid use in a Canadian setting.

Background: While preliminary evidence has begun to document intentional use of one substance to reduce the use of another, the phenomenon of drug substitution among people who use illicit opioids remains understudied. Therefore, we sought to estimate the prevalence and correlates of intentional substance use to reduce illicit opioid use among persons who use drugs (PWUD). Methods: We analysed data from three prospective cohorts of PWUD in Vancouver, Canada, using multivariable generalized estimating equations (GEE). Results: Between June 2012 and June 2016, 1527 participants were recruited and contributed 4991 interviews. Of those, 336 (22%) illicit opioid-using participants self-reported substitution to reduce illicit opioid use at least once during study period contributing 467 (9.4%) interviews. Among those interviews, substances substituted for opioids were alcohol (15 participants, 3.2%), stimulants (235, 50.3%), cannabis (129, 27.6%), benzodiazepines (21, 4.5%), and others (20, 4.3%). In multivariable GEE model adjusted for socio-demographic factors, reporting substitution to reduce illicit opioid use was positively associated with greater likelihood of daily cannabis use (Adjusted Odds Ratio = 1.56, 95% Confidence Interval: 1.24-1.96]. Conclusions: While daily cannabis use was associated with reporting opioid substitution attempts, additional study is needed to examine potential of cannabis/cannabinoids to reduce illicit opioid use.

Remission of Severe Opioid Use Disorder with Ibogaine: A Case Report.

BACKGROUND: Opioid use disorders (OUD) translate into major health, social, and economic consequences. Opioid agonist medications, which generally require long-term administration, are the mainstay pharmacological treatment of OUD. However, a large proportion of individuals with OUD either refuse or fail to respond to these therapies. Ibogaine, a naturally occurring substance found in the Tabernanthe iboga plant, has shown potential to bring about transformative or spiritual experiences that have reportedly been associated with long-term abstinece. Although research on ibogaine is limited, an ibogaine subculture persists, offering unregulated ibogaine preparations for the treatment of addiction. CASE PRESENTATION: We describe the case of a 37-year-old female with a 19-year history of severe OUD achieving an ongoing 18-month period of abstinence following a four-day ibogaine treatment. Her previous longest period of continuous abstinence from opioids was two months while on methadone. No safety issues associated with ibogaine were observed. CONCLUSIONS: A four-day treatment with ibogaine was succesful in achieving long-term remission of a previously treatment-refractory patient with severe OUD. While rigorous trials are required to establish safety and efficacy, future studies should seek to delineate the potential role of ibogaine or other molecules that may produce transformative experiences for individuals with substance use disorder.