Physicians Urge Caution Regarding Medical Uses of Marijuana and Cannabinoids

January 8, 2019

By Will Boggs MD

NEW YORK—While advocates of marijuana and cannabinoids promote its use for conditions ranging from nausea to cancer, the paucity of high-quality evidence demands caution regarding the use of these agents, according to 6 brief commentaries from physicians and other providers across the US.

The editors of Annals of Internal Medicine earlier issued a call for readers' perspectives on prescribing or recommending marijuana. Six of the 100 submitted manuscripts appear in the January 8th issue.

The treatment of pain, one indication where there is some agreement among physicians, is the subject of two of these commentaries.

Dr. Chester B. Good from UPMC Health Plan, Pittsburgh, Pennsylvania and colleagues lament the lack of high-quality evidence and the lack of standardization of medical marijuana (MM) products. Dr. Good told Reuters Health by email, "The opioid epidemic has created a desperate situation in the U.S. Medical marijuana seems to hold some promise for treating pain, but much more evidence is needed. Because marijuana is a Schedule 1 drug, health insurers are not able to provide MM, but there is a great opportunity to study the potential of these products to lower the use of opioids as an option for chronic pain."

"Personally," he said, "I believe that all non-pharmacologic methods for treatment of pain should be pursued prior to the use of drugs for chronic pain, including MM."

Dr. Kevin F. Boehnke and Dr. Daniel J. Clauw from University of Michigan Medical School, Ann Arbor, do not regard cannabinoids as first-line treatments for chronic pain but as adjuvant therapies to be used before opioids if other options fail. Dr. Boehnke told Reuters Health by email, "Cannabis is neither panacea nor poison. As with any other medical intervention, I think it is critical to both be aware of the current evidence and to use good judgment that accounts for the relevant risk/benefit profile. I also believe that keeping cannabis as a Schedule I drug is doing more harm than good, as it is a huge barrier to foundational research that could more accurately guide clinical care, and unnecessarily exposes vulnerable populations (e.g., cancer patients) to untested claims and unreliable products in their search for symptom relief."

For patients planning to use medical cannabis for chronic pain management, Dr. Boehnke offered these suggestions: "1) Be cautious about dosing. Start with very low doses and increase slowly. Use administration routes other than smoking, such as tinctures or edibles. Be aware of whether you are ingesting THC- or CBD-dominant products. To obtain adequate symptom relief, it is often not necessary to feel high (which is caused by THC). Start with CBD and add small amounts of THC if CBD alone is inadequate. 2) Choose products that have been credibly tested for safety and potency. 3) Listen to your body. Use a symptom diary to track how you respond to medical cannabis."

Specific suggestions regarding dosing appear in their commentary.

If the other commentaries are representative, there is less support for the use of medical marijuana in other settings.

Dr. Tina M. Kaufman and colleagues from Oregon Health and Science University, Portland, stress the importance of having thoughtful, open discussions with patients with cardiovascular disease about the hazards associated with marijuana use and potentially guiding them to safer alternatives.

Dr. Kaufman told Reuters Health by email, "Even though marijuana use is now legal in many states and quite prevalent, emerging evidence suggests that smoking marijuana may have risks to cardiovascular health, particularly in older patients and those with known cardiovascular disease. It is important for patients to ask their providers about the potential risks. Although we do not yet have enough data to definitely guide therapy, edibles, oils, and cannabidiol products may possibly be safer alternatives."

What about marijuana use during gestation and lactation? Dr. Eli Y. Adashi from The Warren Alpert Medical School, Brown University, Providence, Rhode Island makes clear in his commentary that the practice should be regarded as harmful until proved safe. He told Reuters Health by email, "Additional research is urgently required in experimental models including non-human primates. Human studies must also proceed albeit in a retrospective mode."

Dr. Adashi concluded, "Marijuana is off limits during gestation and lactation."

Dr. Kennon Heard and colleagues provide another perspective from their emergency department at the University of Colorado School of Medicine in Aurora. Before the easing of federal enforcement there, no children were hospitalized at Colorado's largest pediatric hospital for marijuana exposure. Now, such hospitalizations are common, and they see several each month.

They have also witnessed a dramatic increase in emergency department visits for cannabinoid-related hyperemesis, which was virtually unrecognized before, but now accounts for more than 100 patients a year.

Dr. Heard told Reuters Health by email, "Marijuana has side effects, and patients need to be aware of these if they are going to use it. Some patients will suffer severe effects from marijuana use and end up in the emergency department."

Finally, in her commentary, Dr. Jan K. Carney from Larner College of Medicine at the University of Vermont, Burlington, advocates a strategy that, among other things, aims to eliminate differences between what the public believes about marijuana use and what physicians know.

Dr. Carney told Reuters Health by email, "We need much more scientific evidence about benefits and risks of cannabis and cannabinoids. State-level policy changes have outpaced our rate of scientific understanding, and we need a national research agenda to answer many important (and urgent) questions. There are huge gaps between what we know from research and what is commonly believed."

"Physicians can discuss 'what we know' with patients and also provide patients with sources of high-quality information," she said. "In addition to helping individual patients, physicians must advocate for more research to benefit patients and protect the public."

Dr. Carney added, "There are some excellent resources currently available that summarize what is currently known about benefits and risks of cannabis and cannabinoids. As examples, highlights from the National Academies of Sciences, Engineering, and Medicine report (, the National Institute of Health's Center for Complementary and Integrative Health ( and National Institute on Drug Abuse ( have current and regularly-updated information on their websites."

SOURCES:,,,,, and

Ann Intern Med 2019.

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