Prescriptions for the opioid pain reliever codeine have declined in states that have legalized marijuana, according to a study published in the research journal Health Economics.
The study, published Jan. 18 by researchers from Cornell University, George Mason University, the University of Georgia and the University of Pittsburgh, is based on data analyzing opioid shipments from 11 states that have legalized cannabis for adult use.
The study period was between 2010 and 2019 and compared legal marijuana states to those that still ban the federally illegal Schedule I drug.
The researchers stated that their study examined the effect of legal recreational marijuana on prescription opioids across all payers and endpoints, including pharmacies, hospitals, and specialists.
The study took into account factors such as opioid prescribing thresholds, and it looked at different types of opioids, including codeine.
They determined that states that have legalized recreational cannabis use have seen about a 26% reduction in the amount of codeine dispensed at dispensaries, and that the results are “potentially promising from a public health perspective.”;
Codeine, the researchers said, is a class of opioids that appears to be used non-medically compared to other prescription opioids.
The team said their study differs from previous studies that have looked at recreational marijuana laws and how they affect opioid prescriptions funded by private and public payers or dispensed to unique endpoints.
According to the researchers, a total of 21 states have now legalized recreational marijuana.
Thirty-seven states, including Washington, DC, have medical cannabis programs, according to the National Organization for the Reform of Marijuana Laws.