By Pauline Anderson
Nearly a third of patients with chronic pain report using medical cannabis to manage that pain, and more than half of them reduce their use of other pain medications, including opioids, according to new research.
"That patients are reporting their substitution of cannabis for pain medication really underscores the need for research on the benefits and risks of using cannabis for chronic pain," lead author Mark C. Bicket, MD, PhD, assistant professor, Department of Anesthesiology and director, Opioid Prescribing Engagement Network, University of Michigan, Ann Arbor, told Medscape Medical News.
However, she added, the question is whether they are turning to cannabis and away from other pain treatments. "What's unclear, and one of the gaps we wanted to address in the study, is whether medical cannabis use is changing the use of other treatments for chronic pain," Bicket said.
The study was published online on January 6 in JAMA Network Open.
Decreased opioid use
The survey included a representative sample of 1724 American adults aged 18 and over with chronic non-cancer pain who live in areas with a medical cannabis program.
Respondents were asked about their use of three categories of pain treatments. These included medical cannabis; drug treatments, including prescription opioids, non-opioid pain relievers, and over-the-counter pain relievers; and common non-drug treatments such as physical therapy, meditation, and cognitive behavioral therapy (CBT).
Just over 96% of respondents completed the entire survey. Approximately 57% of the sample was female, and the average age of the study sample was 52.3 years.
Among the study participants, 31% (95% CI, 28.2% – 34.1%) reported using cannabis to manage pain; 25.9% (95% CI, 23.2% – 28.8%) reported use in the past 12 months, and 23.2% (95% CI, 20.6% – 26%) reported use in the past 30 days.
"This translates into a large number of people who are using cannabis in an intended medical way" to treat chronic conditions such as lower back pain, migraines, and fibromyalgia, Bicket said.
More than half of those surveyed reported that their medical cannabis use led to a decrease in prescription opioid use, non-opioid prescription use, and over-the-counter drug use.
Bicket noted that "almost no one" said that the use of medicinal cannabis led to increased use of these drugs.
Regarding non-pharmacological treatments, 38.7% reported that their cannabis use led to a decrease in physiotherapy use, 19.1% to a decrease in meditation use, and 26% to a decrease in CBT. At the same time, 5.9%, 23.7%, and 17.1%, respectively, reported that it led to an increase in physiotherapy use.
Medical cannabis is regulated at the state level. At the federal level, it is considered a Schedule I substance, meaning it is deemed to have no therapeutic use, although some groups are trying to change that categorization, Bicket said.
As a result, cannabis products "are quite variable" in terms of how they are used (smoked, eaten, etc.) and in their composition, including the percentage of cannabidiol (CBD) and tetrahydrocannabinol (THC).
“We really don’t have a good idea of the relative risks and benefits that might come from cannabis as a treatment for chronic pain,” Bicket said. “As a physician, it’s difficult to have conversations with patients because I can’t understand the products they’re using based on this regulatory environment we have.”
He added that doctors "are operating in an area of uncertainty at the moment."
What is needed is research to determine how safe and effective medicinal cannabis is for chronic pain, he said.
Pain is a primary indication
Commenting on the findings from Medscape Medical News, Jason W. Busse, PhD, professor in the Department of Anesthesia and associate director of the Centre for Medicinal Cannabis Research at McMaster University in Hamilton, Canada, said the study reinforces the results of some previous research.
"It gives us current information that undoubtedly highlights the high rate of medicinal cannabis use among people with chronic pain once it becomes legally available."
Furthermore, this high rate of use "means we desperately need information about the benefits and harms" of medical marijuana, he said.
Busse noted that the survey did not provide information on the types of cannabis used or the method of administration. Oil drops and sprays cause less lung damage than smoked versions, he said.
Furthermore, it is not clear from the survey whether participants are taking formulations with high levels of THC that are associated with an increased risk of harm, he said.
He noted that cannabis can interact with prescription medications to make them less effective or, in some cases, to increase their adverse effects.
Busse noted that some patients may be using fewer opioids because providers are under "enormous pressure" to reduce prescriptions of these drugs in the wake of spikes in opioid overdoses and deaths.
Chronic pain is “absolutely the primary indication” for medical marijuana, Busse said. U.S. reimbursement data suggests that up to 65% of people obtain cannabis to treat a listed indication for chronic pain.
He said he hopes this new study will increase interest in funding new trials "so that we can have better evidence to guide practice and help patients make decisions."
The study received support from the National Institute on Drug Abuse (NIDA).
Bicket reported receiving grants from the National Institutes of Health, the Centers for Disease Control and Prevention, the Michigan Department of Health and Human Services, the Arnold Foundation, and the Patient-Centered Outcomes Research Institute, as well as personal fees from Axial Healthcare, outside of the work submitted. Busse does not report any relevant financial relationships.
JAMA Open Network. Published online January 6, 2023. Research Letter