States that permit recreational use of cannabis see a reduction in demand for prescription codeine, an opioid with a high potential for misuse.

Published Jan. 19 in Health Economics, a new study finds a significant reduction in pharmacy-based codeine distribution in states that have legalized recreational cannabis use. The finding is promising from a public health policy perspective because misuse of prescription opioids annually contributes to more than 10,000 overdose deaths.

Twenty-one U.S. states have passed recreational cannabis laws and legislatures in other states are considering similar measures.

“A reduction in the misuse of opioids will save lives,” said doctoral candidate Shyam Raman who is affiliated with the Cornell Jeb E. Brooks School of Public Policy and the lead author. “Our research indicates that recreational cannabis laws substantially reduce distribution of codeine to pharmacies, an overlooked potential benefit to legalizing recreational cannabis use.”

The study is believed to be among the first to separately examine the impact of recreational cannabis laws on shipments of opioids to hospitals, pharmacies and other endpoint distributors. Previous studies have focused on medical cannabis laws or use of opioids by subsets of consumers, such as Medicaid beneficiaries.

The researchers analyzed data from the Drug Enforcement Administration’s Automation of Reports and Consolidation Orders System which tracks the flow of controlled substances in the U.S.

Key findings from states that passed recreational cannabis laws:

• A 26% reduction in pharmacy-based distribution of codeine and as much as a 37% reduction after recreational cannabis laws have been in effect for four years.
• Minimal impact on distribution of other opioids such as oxycodone, hydrocodone and morphine in any setting.
• Minimal impact on codeine distribution by hospitals, which often have less permissive policies than pharmacies.

“This finding is particularly meaningful,” said senior author Coleman Drake of the University of Pittsburgh’s School of Public Health. “Where previous studies have focused on more potent opioids, codeine is a weaker drug with a higher potential for addiction. It indicates people may be obtaining codeine from pharmacies for misuse, and that recreational cannabis laws reduce this illicit demand.”

Additional authors on the research are W. David Bradford of the University of Georgia and Johanna Catherine Maclean, Ph.D. ’12, now of George Mason University.

Maclean said that while cannabis and opioids can be used to minimize chronic pain symptoms, they aren’t equivalent in their impact on health. “Increasing legal access to cannabis may shift some consumers away from opioids and toward cannabis,” she said. “While all substances have some risks, cannabis use is arguably less harmful to health than the nonmedical use of prescription opioids.”

The research was supported by the National Institute on Drug Abuse of the National Institutes of Health.

Jim Hanchett is assistant dean for communications for the Cornell Jeb E. Brooks School of Public Policy.