The impact of cannabis on non-medical opioid use among individuals receiving pharmacotherapies for opioid use disorder: a systematic review and meta-analysis of longitudinal studies

ABSTRACT

Background: The relationship between cannabis use and the risk of returning to using opioids non-medically during treatment for opioid use disorder (OUD) remains unclear.

Objective: We sought to quantify the impact of cannabis use on the risk of non-medical opioid use among people receiving pharmacotherapies for OUD.

Methods: A comprehensive search was performed using multiple databases from March 1 to April 5 of 2023. Eligible studies longitudinally assessed the association between cannabis use and non-medical opioid use among people with OUD receiving treatment with buprenorphine, methadone, or naltrexone. We utilized a random-effects model employing the restricted maximum likelihood method. A sensitivity analysis was conducted to understand potential differences between each OUD treatment modality.

Results: A total of 10 studies were included in the final meta-analysis. There were 8,367 participants (38% female). The average follow-up time across these studies was 9.7 months (SD = 3.77), ranging from 4 to 15 months. The pharmacotherapies involved were methadone (76.3%) buprenorphine (21.3%), and naltrexone (2.4%). The pooled odds ratio did not indicate that cannabis use significantly influenced non-medical opioid use (OR: 1.00, 95% CI: 0.97–1.04, p = .98). There is evidence of moderate heterogeneity and publication bias.

Conclusion: There was no significant association between cannabis use and non-medical opioid use among patients receiving pharmacotherapies for OUD. These findings neither confirm concerns about cannabis increasing non-medical opioid use during MOUD, nor do they endorse its efficacy in decreasing non-medical opioid use with MOUD. This indicates a need for individualized approaches for cannabis use and challenges the requirement of cannabis abstinence to maintain OUD pharmacotherapies.

KEYWORDS:

• Cannabinoids
• opioid sparing effects
• relapse
• harm reduction
• buprenorphine
• methadone
• naltrexone

Acknowledgments

We thank Dr. David Epstein for sharing the relevant data from his previously published paper and for assisting us in accurately interpreting and analyzing this data.

Disclosure statement

The authors report no relevant disclosures. JPD has been supported in clinical trials by Jazz Pharmaceuticals, specifically through medication provisions. Additionally, JPD has been a compensated consultant for Boehringer Ingelheim.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00952990.2023.2287406

Additional information

Funding

Joao P. De Aquino is supported by the grants [K23DA052682] and [R21DA057240] from the National Institute on Drug Abuse (NIDA) and Doris Duke Charitable Foundation.