By David Boctor M.D.

Many clinicians are still skeptical of cannabis as a viable treatment option, either due to the stigma surrounding cannabis use or the belief that there is not enough clinical evidence for them to feel confident providing patients with cannabis recommendations. The fact of the matter is most medical schools offer no education on medical cannabis through the years of medical school or post-graduate years.

So how do we answer skeptics in the healthcare field, who are still not sure about the medical effects of this ancient plant? Do these skeptical thoughts still surround other plants that give rise to medicine?

Drugs Plant Indication
Aspirin White Willow

Winter green


Quinine Cinchona calisaya tree from South America. Anti-malaria



Opium poppy Pain management
Penicillin A type of mould Antibiotic
Digoxin Foxglove Heart failure
Paclitaxel Pacific Yew Chemotherapeutic


Madagascar periwinkle plant Chemotherapeutic


During one of my outreach sessions, a fairly skeptical physician asked me point blank, “Why should I bother considering adding medical cannabis to my patients’ pain management, and is there any empirical evidence to support those supposed claims?”

Aside from saying that the CB-1 receptors are located in the brain in these regions, and the patient reported evidence we’ve seen, I didn’t have any further in depth knowledge. With that I embarked on a literature review to see how I can back-up those claims.

The endocannabinoid and opioidergic systems are known to interact in many different ways, from the distribution of their receptors to cross-sensitization of their behavioral pharmacology. Cannabinoid-1 (CB1) receptors and 𝝁-opioid receptors (MORs) are distributed in many of the same areas in the brain. The extent of this overlap and frequent spatial overlap of the two different types of receptors offers a clear morphological justification for interactions between the opioid and cannabinoid systems in reward and withdrawal.

The primary use for both prescription opioids and cannabis is for pain management. The National Academies of Science and Medicine performed a meta-analysis on the efficacy of cannabis for chronic pain in adults and found two things of importance.

  1. When given access to cannabis, individuals currently using opioids for chronic pain decrease their use of opioids by 40–60% and report that they prefer cannabis to opioids.
  2. Patients in these studies reported fewer side effects with cannabis than with their opioid medications (including a paradoxical improvement in cognitive function) and a better quality of life with cannabis use, compared to opioids. (2)


One possible explanation of the opioid sparing effects of cannabis is that of “synergistic analgesia”. Subanalgesic doses of THC and morphine are equally unsuccessful at reducing sensory pain; however, when the same doses are coadministered, they produce a significant reduction in the affective component of pain.

The data suggests that analgesic synergy produced by coadministered cannabis and opioids could be harnessed to achieve clinically relevant pain relief at doses that would normally be subanalgesic. This strategy could have significant impacts on the opioid epidemic, given that it could entirely prevent two of the hallmarks of opioid misuse: dose escalation and physical dependence.(3)

In addition, patients report substituting cannabis for several types of pharmaceutical drugs, including opioids, benzodiazepines, and antidepressants. Patients report that their reasons for substituting cannabis for other medications include less severe side effects, less withdrawal potential, ease of access, and better symptom management for their conditions.

As the field continues to evolve and rapidly continue to shape-shift at the rate it has been going, it will be of utmost importance for clinicians to participate in Continuing Medical Education programs, which include the harm reduction and medical benefits that cannabis could provide. Evidence-based opioid prescription and cannabis recommendation practices are a critical component of continuing education, so that clinicians can continue to uphold their Hippocratic oaths to “do no harm.”

This is why a partnerships and a referral system with Harvest Medicine makes sense for their practice. With over 4.5 million data points collected, HMED has created an outstanding patient-focused approach to the prescribing and education of medical cannabis.



  1. Cooke, J. (2018, June 22). 9 Famous Examples of Drugs That Came From Plants. Retrieved March 21, 2019, from
  2. Groce, E. (2018). The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. Journal of Medical Regulation,104(4), 32-32. doi:10.30770/2572-1852-104.4.32
  3. Budney, A. J., Stanger, C., Knapp, A. A., & Walker, D. D. (2018). Status Update on the Treatment of Cannabis Use Disorder. Oxford Clinical Psychology. doi:10.1093/med-psych/9780190263072.003.0010


About the Author:

David Boctor is an ECFMG certified medical doctor. David has consulted for the Canadian Cancer Society’s cancer information service. He also spent 5 years with Trillium Gift Life Network working for the organ and tissue donation service in Ontario. David has great depth of knowledge in clinical pain management and optimizing therapeutic outcomes, and currently works out of Harvest Medicine’s Toronto clinic.


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