The legalization of marijuana in Colorado is associated with a significant reduction in prescription opioid distribution, according to a new study published in the International Journal of Environmental Research and Public Health. The study was first reported on by NORML.
For the study, researchers with the Geisinger Commonwealth School of Medicine in Pennsylvania and the University of New England in Maine examined opioid distribution trends in Colorado following legalization as compared to trends in two control states, Utah and Maryland. They examined dispensing trends for nine prescription opioids used for pain (e.g., fentanyl, morphine, hydrocodone, hydromorphone, and oxycodone) as well as for methadone and buprenorphine, which are primarily prescribed to treat opioid use disorder (OUD).
The study reports a greater than 30% reduction in opioid dispensing in Colorado between 2007 and 2017. According to NORML, “That reduction was significantly larger than what was observed in the control states over the same period of time. However, because the study design was observational in nature, authors could not determine whether legalization was independently responsible for the change.”
Researchers conclude by stating: “In this study, we observed dynamic changes in opioid distribution for eleven opioids used for pain and OUD within Colorado, and two carefully selected comparison states, Utah and Maryland, from 2007 to 2017. Colorado, after legalizing recreational marijuana, had a significant decrease in prescription opioids distributed for pain. The findings from this geographically limited study were challenging to interpret because, while analgesic opioid use was unchanged in Utah, Maryland also had a significant decline [though this decline was not as significant as was observed in Colorado.] Other national research more clearly showed that marijuana policies were associated with reductions in analgesic opioid use. This appears to be an empirically informed public policy strategy which may contribute to reversing the US opioid epidemic.”
The full abstract of the study, titled Prescription opioid distribution after the legalization of recreational marijuana in Colorado, can be found below:
There have been dynamic changes in prescription opioid use in the US but the state level policy factors contributing to these are incompletely understood. We examined the association between the legalization of recreational marijuana and prescription opioid distribution in Colorado. Utah and Maryland, two states that had not legalized recreational marijuana, were selected for comparison. Prescription data reported to the Drug Enforcement Administration for nine opioids used for pain (e.g., fentanyl, morphine, hydrocodone, hydromorphone, oxycodone, oxymorphone) and two primarily for opioid use disorder (OUD, methadone and buprenorphine) from 2007 to 2017 were evaluated. Analysis of the interval pre (2007-2012) versus post (2013-2017) marijuana legalization revealed statistically significant decreases for Colorado (P < 0.05) and Maryland (P < 0.01), but not Utah, for pain medications. There was a larger reduction from 2012 to 2017 in Colorado (-31.5%) than the other states (-14.2% to -23.5%). Colorado had a significantly greater decrease in codeine and oxymorphone than the comparison states. The most prevalent opioids by morphine equivalents were oxycodone and methadone. Due to rapid and pronounced changes in prescription opioid distribution over the past decade, additional study with more states is needed to determine whether cannabis policy was associated with reductions in opioids used for chronic pain.