The evidence of cannabis’ potential value as an opioid substitute continues to mount.
A study published last month shows, for the first time, that smoking marijuana while taking a prescription opioid can lessen the opioid dose needed to provide pain relief.
The finding suggests that using the two drugs together might enable patients to benefit from a prescription opioid’s pain-killing effects, while running less risk of addiction and other unwanted side effects accompanying high-dose opioid usage.
The study, published in the February 20, 2018, issue of Neuropsychopharmacology, tested the pain-relieving impact of a very low—ordinarily ineffective—dose of oxycodone, 2.5 mg, when administered alone and in combination with cannabis.
“When taken separately,” explains lead-author Ziva D. Cooper, Ph.D., in an interview, “neither cannabis nor the low-dose oxycodone were effective for reducing pain. But when taken together, pain responses were significantly reduced, pointing to the potential opioid-sparing effects of cannabis.” Cooper is an associate professor in clinical neurobiology at the Columbia University Department of Psychiatry.
The notion that cannabis—and cannabinoids, including prescription drugs like Marinol—could serve as a substitute for opioid drugs for treating chronic pain has been suggested by multiple earlier studies, as well as anecdotal clinical observation. Reviewing the literature in January 2017, the National Academies of Science, Engineering and Medicine concluded that there is “substantial evidence that cannabis is an effective treatment for chronic pain in adults.” (Cooper was on the committee that wrote that report.) A study later that year found that hospitalizations for opioid addiction and overdose dropped 23% and 13%, respectively, in states that legalized medical marijuana, while a 2014 JAMA Internal Medicine study concluded that opioid overdose deaths fell 25% in those states. Similarly, a group of 244 medical cannabis users in Michigan reported a 64% drop in their use of opioids to treat chronic pain, according to survey-based research published in the Journal of Pain in 2016.
Cooper’s investigation, which was supported by a U.S. National Institute on Drug Abuse grant, was double-blind and placebo-controlled. The 18 participants were healthy volunteers, aged 21 to 45, who already smoked marijuana regularly. To measure pain response the authors used a common test in which participants submerged one hand in ice-cold water for as long as they could stand.
The study used smoked marijuana—notwithstanding its potential respiratory issues—because it is still the most common way cannabis is used, Cooper explains in an interview.
Of course, this study alone, on healthy individuals, tells us nothing conclusive about how effective an opioid substitute cannabis would be for patients battling severe chronic pain—estimated to constitute about 11% of the adult population, or more than 25 million people. But it does encourage further exploration.
Alas, such research remains difficult, hampered by the regulatory environment. Marijuana is still a Schedule I controlled substance, meaning that—like heroin and LSD—the Drug Enforcement Administration deems it to have no accepted medical use and bans doctors from prescribing it. This is so even though 29 states and the District of Columbia have now legalized the substance for at least some medical uses.
Nearly all university research is federally funded, and there is only one lawful source of marijuana for such work: a DEA-licensed farm at the University of Mississippi. Though the Obama Administration invited additional applications for licenses in 2016, and reportedly received 25 submissions, the Trump Administration has issued no new licenses.
President Trump’s Attorney General, Jeff Sessions, has long been an unstinting opponent to marijuana, and earlier this year he threatened to bring criminal prosecutions against vendors in states that have legalized it for any purpose. He also reasserted last month his private hunch, unmoored in empirical research, that marijuana is a more important gateway drug to opioid addiction than are prescription opioids.
In fairness to him, cannabis is no miracle drug, devoid of danger. The same National Academies paper that endorsed its value in treating chronic pain, warned of use disorders that some consumers develop, and found “substantial evidence” that the drug was statistically associated with increased risk of motor vehicle crashes and with the development of schizophrenia and other psychoses, with the highest risk among the most frequent users.
Basically, there’s no free lunch.