“Twenty-one U.S. states have passed recreational cannabis laws as of November 2022. Cannabis may be a substitute for prescription opioids in the treatment of chronic pain. Previous studies have assessed recreational cannabis laws’ effects on opioid prescriptions financed by specific private or public payers or dispensed to a unique endpoint.

Our study adds to the literature in three important ways: by (1) examining these laws’ impacts on prescription opioid dispensing across all payers and endpoints, (2) adjusting for important opioid-related policies such as opioid prescribing limits, and (3) modeling opioids separately by type. We implement two-way fixed-effects regressions and leverage variation from eleven U.S. states that adopted a recreational cannabis law (RCL) between 2010 and 2019.

We find that RCLs lead to a reduction in codeine dispensed at retail pharmacies. Among prescription opioids, codeine is particularly likely to be used non-medically. Thus, the finding that RCLs appear to reduce codeine dispensing is potentially promising from a public health perspective.”

https://pubmed.ncbi.nlm.nih.gov/36653623/

https://onlinelibrary.wiley.com/doi/10.1002/hec.4652

“When recreational cannabis is legal, codeine demand drops”

https://news.cornell.edu/stories/2023/01/when-recreational-cannabis-legal-codeine-demand-drops