Pot legalization tied to drop in opioid prescribing rates

Results of these two investigations suggest that the legalization of marijuana may help combat the opioid crisis, but more rigorous investigations are needed, according to Kevin P. Hill, MD, and Andrew J. Saxon, MD.

The new studies show an association between state marijuana laws and fewer opioid prescriptions in Medicare and Medicaid populations.

Those findings do support previous investigations of administrative data sets suggesting that cannabis legalization policies are associated with reductions in opioid use and mortality, Dr. Hill and Dr. Saxon said in an editorial.

However, not all studies suggest that cannabis replaces opioid use, according to the authors, who cited a study suggesting an association between illicit cannabis use and subsequent cannabis use.

“The association between illicit cannabis use and opioid use may be different than the association of legalized cannabis use and opioids,” the editorial authors wrote. “Nevertheless, the findings demonstrating that cannabis use is associated with initiation of or increase in opioid use underscores the fact that rigorous scientific studies are needed.”

Those studies should focus not only analysis of policies on legal medical and recreational cannabis but also on clinical trials of cannabis and cannabinoids for chronic pain and other conditions where opioids are used, they added.

One limitation of the studies is that Medicare and Medicaid populations generally represent individuals who are disabled, older, and lower income, limiting the ability to generalize to other demographics, according to the authors.

Nevertheless, the authors wrote, a decrease tied to legal marijuana availability would “dovetail” with preclinical evidence that cannabinoid and opioid receptor systems mediate signaling pathways involved in tolerance, dependence, and addiction.

“These concepts support anecdotal evidence from patients who describe a decreased need for opioids to treat chronic pain after initiation of medical cannabis pharmacotherapy,” the authors wrote.

Kevin P. Hill, MD, is with the division of addiction psychiatry at Harvard Medical School and Beth Israel Deaconess Medical Center, both in Boston. Andrew J. Saxon, MD, is with the Center of Excellence in Substance Abuse Treatment and Education at the VA Puget Sound Healthcare System, and the department of psychiatry and behavioral sciences at University of Washington, both in Seattle. These comments are derived from their editorial (JAMA Intern Med. 2018 Apr 2. doi: 10.1001/jamainternmed.2018.0254). The authors reported no conflicts of interest.