A lack of clinical trials is keeping some addictions experts from recommending medical marijuana as a potential treatment for opioid abusers.
Within the past year, the use of medical marijuana to help people overcome opioid addiction has risen in popularity. States like Illinois are even allowing patients to switch from using opioids to medical marijuana to treat conditions such as chronic pain and opioid use disorder. And while many advocates say medical marijuana can be an effective means of fighting opioid addictions, some experts believe "substituting cannabis for opioid addiction treatments is potentially harmful."
"The conversation has generally assumed cannabis to be safer and as effective as opioids, but it isn't clear what the truth is," Dr. Richard Saitz - Chair of the Department of Community Health Sciences at Boston University's School of Public Health - told Medscape Medical News.
Saitz - who was formerly the director of Boston Medical Center's Clinical Addiction Research and Education Unit - recently co-authored an article arguing that current research doesn't support medical marijuana as an effective treatment for opioid use disorder. There just haven't been enough high-quality studies conducted to promote the use of cannabis in this way, says Saitz.
"The suggestion that patients should self-substitute a drug (ie, cannabis) that has not been subjected to a single clinical trial for opioid addiction is irresponsible and should be reconsidered," Saitz and co-author Dr. Keith Humphreys - Professor of Psychiatry and Behavioral Sciences at Stanford University - wrote in their article.
The studies that have been done, according to Saitz and Humphreys, actually show that "medical cannabis use was positively associated with greater use and misuse of prescription opioids." On top of this, the evidence that cannabis is an effective treatment for neuropathic pain is "low-strength" at best, they argue meaning that the chronic pain patients most frequently prescribed opioids might not get the treatment they need if they substitute their medications with cannabis.
And while studies have shown that states with medical marijuana programs have lower rates of opioid abuse, Saitz and Humphreys say those studies don't consider many other factors that may contribute to lowered opioid-related deaths.
"The methodological concern with such studies is that correlation is not causation. Many factors other than cannabis use may affect opioid overdose deaths, such as prescribing guidelines, opioid rescheduling, Good Samaritan laws, incarceration practices, and availability of evidence-based opioid use disorder treatment and naloxone."
This doesn't mean that Saitz and Humphreys think marijuana lacks medicinal value. They just aren't prepared to recommended it as as substitute for opioid patients just yet.
"Cannabis and cannabis-derived medications merit further research, and such scientific work will likely yield useful results," they said. "This does not mean that medical cannabis recommendations should be made without the evidence base demanded for other treatments."
Saitz and Humphreys' call for more marijuana research is of course justified. The substance remains one of the most difficult to study in the US and most scientists would agree there is still a lot we can learn about the plant. However, one thing seems clear. Medical marijuana continues to be a far safer option for patients than traditional opioid-based medications and a lot of harm could be avoided by simply not prescribing opioids to begin with.