Medical Cannabis Research: A Physician’s Perspective on Pain and Potential

By Dr. Stephen M. Dahmer, Chief Medical Officer of Vireo Health

 Being an “expert” in diverse disciplines as required by the profession of family medicine requires a quick ability to gather facts and clear awareness of our own limitations. We all know facts can be interpreted and even influenced in many ways.

As physicians, we need to be aware of those influences, including our own biases when interpreting information used to treat patients. We must assess the data and the clinical context to objectively compare a treatment to what is already standard of care in our profession. With over two years of my career focused on medical cannabis (MC) as the Chief Medical Officer of Vireo Health, I’m eager to share what I have both seen and learned.

Never before in my career have I come across a medicine that carries such stigma, preventing most from taking a truly objective look at the pros and cons of its use in treating disease. Never before have I worked with a medicine that made its way to the medical community on the backs of patients and their families. Never before have I seen a plant-based medicine—with such potential for healing—face such tremendous hurdles to reach those invisible patients who would benefit most.

“If cannabis were unknown, and bioprospectors were suddenly to find it in some remote mountain crevice, its discovery would no doubt be hailed as a medical breakthrough. Scientists would praise its potential for treating everything from pain to cancer, and marvel at its rich pharmacopoeia—many of whose chemicals mimic vital molecules in the human body.” The Economist, April 27, 2006

Evidence for the use of medical cannabis to treat chronic pain is substantial, and growing exponentially

A quick search reveals 695 current clinical trials related to the search term “cannabis.” Randomized controlled trials (RCTs) (Wilsey, 2008; Ellis, 2009; Wallace, 2015; Ware, 2010; Abrams, 2007), systematic reviews, meta-analyses, and even expert opinion all support various medical benefits of using MC to treat pain.

They also support the need for additional high-quality research. Evidence also shows patients are substituting MC for opioids, using less medications across the board, and dying less from opioid overdose when MC is a legal and available option.

Take a look at one of my favorite numbers in medicine: the number needed to treat (how many patients must be treated for one to benefit) for MC in painful sensory neuropathy when compared to other accepted treatments. Spoiler alert: Only one pharmaceutical surpasses MC.

In a practical clinical setting, many of our patients with chronic pain have already tried physical therapy, acupuncture, over-the-counter meds, and/or mind-body therapies. When face-to-face with that patient on a busy day, we are left with few additional options, yet we want alternatives to fill this void.

When left with few options, unfortunately, opioids have too often become the remedy for our own pain. We are now bearing witness to the consequences of such a remedy. So many unfortunate deaths related to opioids are only the tip of the iceberg. Adverse effects related to non-steroidal anti-inflammatory drugs (NSAIDs) and sedative hypnotics (depressants), and their potential to kill demand more open discussions with our patients.

When discussing MC with our patients, quality of product should be our highest concern. Similar to any other medical treatment, consistency and precision are indispensable. In New York and Minnesota, all products are third-party-tested for heavy metals, growth regulators, and fungal and bacterial contaminants, and must have within 5 to 10% of the stated dose of major cannabinoids (THC and CBD). Any substance that is used to treat disease in our sickest patients should demand such rigor.

All medications have a shadow side; awareness is key
Years of clinical experience have also taught me there is no medication lacking a shadow side. While a virtually non-existent LD50 (an inability to die from an overdose of cannabis) was one of the main motivating factors for me to approach this as a physician, this plant is NOT without potential for harm. MC is NOT for everyone!

CM is contraindicated in patients with a history of psychotic illness (or family history of a first-degree relative with schizophrenia), active unstable heart disease, or an allergy to cannabis (thankfully very rare). Women should not use MC during pregnancy or while breastfeeding. MC use is inadvisable in patients taking other psychoactive or sedative medications and patients with severe liver or kidney disease. MC should be used with caution by patients with a history of substance or alcohol abuse. Patients using MC should avoid driving. Any patient who is at risk for falling should use with extreme caution. Both physician and patient should be aware of interactions with other medications.

The MC mantra is “start low and go slow.” This shadow side only reinforces that what our patients need most is education. Complete disdain towards any complementary therapy only promotes false hopes, patient misinformation and mistrust.

Irrespective of your stance regarding MC and the myriad diseases it potentially treats, we are all long overdue on learning more about the fascinating internal regulator called the endocannabinoid system (ECS). The ECS is a prohomeostatic endogenous modulatory system with enormous potential to improve health and alleviate suffering.

Physiologically, the ECS has been shown to impact pain perception, movement, appetite, aversive memory extinction, hypothalamic-pituitary-adrenal (stress) axis modulation, immune function, mood, inflammation, and more. It is time we tossed aside unnecessary stigma and improved our familiarity with MC risks, benefits, and its role in improving health.

The time is now to explore the benefits of medical cannabis

Some estimates reveal 1.2 million patients in the U.S. utilize medical cannabis legally. The train has already left the station.

MC may just be the parachute that helps our medical community out of a steep freefall. As we sort out many of the details, the patients themselves push me forward. And their stories are astounding.

Let us learn from past mistakes and exercise caution as we should with any therapy. Patients and physicians alike must be aware of, and openly discuss, both risks AND benefits. Patients should not be afraid to breach the subject with their doctors. Doctors should be knowledgeable and open to discussing possible benefit AND potential for harm for each individual patient.

Despite research challenges and a lack of standardization across the U.S., MC could potentially be a beneficial adjuvant on all steps of the analgesic ladder. We should demand the high-quality research needed to be certain of that. At Vireo, we are eager to begin working with Albert Einstein College of Medicine and Montefiore Health System on a $3.8 million National Institutes of Health (NIH) Federal research grant to study MC and chronic pain. We will share updates as we have them at

About Dr. Dahmer:

Dr. Stephen M. Dahmer is a board-certified family doctor and Chief Medical Officer of Vireo Health. A fellow of the Arizona Center for Integrative Medicine, he has studied the relationships between plants and people for over a decade. Dr. Dahmer is also Assistant Clinical Professor of Family Medicine and Community Health at the Icahn School of Medicine at Mount Sinai in New York City.