Latest posts by Philippe Lucas, Ph.D. (C) (see all)


North America is currently in the grips of a public health crisis rooted in the use of licit and illicit opioid-based analgesics. Drug overdose is the leading cause of accidental death in Canada and the US, and on April 26, British Columbia reported 130 opioid-related overdoses emergency calls in a single day. In light of the growing amount of research suggesting that medical cannabis use can reduce the use of prescription opioids and other substances.

Can medical cannabis play a role in reducing the morbidity and mortality associated with opioids?

A 2015 cross sectional survey of patients in Canada’s national medical cannabis system found that 63% of respondents reported substituting cannabis for prescription drugs (n=166), with 32% of the pharmaceuticals being substituted for being prescription opioids (n=80) (Lucas & Walsh, 2017).


Research has found that medical cannabis programs are associated with a reduction in the use of opioids and associated morbidity and mortality. Bachhuber, Salone, Cunningham and Barry (2014) report that U.S. states with medical cannabis laws had a 24.8% lower mean annual opioid overdose mortality rate compared to states without medical cannabis laws. A 2015 cross sectional survey of patients in Canada’s national medical cannabis system found that 63% of respondents reported substituting cannabis for prescription drugs (n=166), with 32% of the pharmaceuticals being substituted for being prescription opioids (n=80) (Lucas & Walsh, 2017).

These and other findings on cannabis substitution effect suggests there may be three important windows of opportunity for cannabis for therapeutic purposes (CTP) to play a role in the opioid use and dependence cycle:

  • 1) prior to opioid introduction in the treatment of chronic pain;
  • 2) as an opioid reduction strategy for those already using opioids; and
  • 3) as an adjunct therapy to methadone or Suboxone treatment in order to increase treatment success rates.


Chronic pain is the most common indication reported by Canadian and US patients who use medical cannabis (Walsh et al., 2013; Boehnke, Litinas & Clauw, 2016), and epidemiological studies by Bachhuber, Salone, Cunningham and Barry (2014) and Bradford and Bradford (2016) strongly suggest that access to medical cannabis through state-level programs in the US reduces opioid use and related harms.

In light of this data, it would make sense to consider how the prescription use of cannabis in the treatment of chronic pain might interrupt the cycle of opioid use and dependence by not introducing opioids into the course of care in the first place. However, there exist some systemic challenges to this potential harm reduction strategy, foremost of which is that while opioids remain second line treatment options throughout North America, clinical guidelines in Canada designate cannabis a third or fourth line treatment option for pain. The growing body of research suggesting that cannabis is a far safer, less addictive option than prescription opioids in the treatment of chronic pain creates a strong rationale to review and modernize these policies in order to reduce the increasingly detrimental impacts of the current opioid crisis.


For those patients that are already using opioids in their course of care, the therapeutic imperative is to ensure treatment success without a progression to dependence and/or overuse. Evidence suggests that cannabis can be a useful adjunct therapy in meeting these goals. Cannabis augments the pain relieving potential of opioids (Abrams, Couey, Shade, Kelly & Benowitz, 2011), and can re-potentiate their effects (Cichewicz, 2004), thereby reducing the need to increase the dosage of opioid pain medications.


When opioid use graduates to dependence, it is imperative that users seeking opioid replacement therapy (ORT) have the greatest possible chance of success, and some research has found that cannabis use can positively impact treatment success rates. Intermittent cannabis users showed superior retention in naltrexone treatment compared to abstinent or consistent users (Raby et al., 2009), and objective ratings of opioid withdrawal decreased in patients concurrently using cannabis during the early stages of methadone stabilization (Scavone, Sterling, Weinstein, & Van Bockstaele, 2013). Since there is an exceedingly high risk or relapse and overdose in this dependent population, systematic research-based strategies to explore the potential of medical cannabis to improve ORT success rates should be implemented immediately.

access to quality-tested medical cannabis products labeled for THC and CBD content

Canada may be particularly well positioned to implement these proposed interventions. With a long-standing federally regulated medical cannabis program that currently serves over 160,000 Canadians with physician support for medical cannabis, and access to quality-tested medical cannabis products labeled for THC and CBD content, outreach and education to health care practitioners touting the three opportunities for cannabis-based interventions could be accomplished very quickly, and could thereby have nearly immediate impacts on opioid use.

Since a number of provinces have centralized tracking of prescription drug dispensing, detailed real-time data on the use of prescription opioids would be available to measure the population-level impacts of these interventions. This information could be coupled with well-designed epidemiological studies tracking overdose rates through first responder calls and emergency room data, as well as prospective observational cohort studies comparing methadone/Suboxone treatment success rates in cannabis and non-cannabis using populations.

Tilray has recently teamed with Ontario addiction treatment specialist Dr. Peter Farago

In regards to the latter, Tilray has recently teamed with Ontario addiction treatment specialist Dr. Peter Farago to design and implement the Substitution of Opioid Study (S.O.S.), a cohort study that will compare the success rate of methadone and/or Suboxone treatment in cannabis using and non-cannabis using patients in order to better understand the role that cannabis plays in ORT. The study is designed to take place at 5 ORT clinics in Ontario and BC, and was launched in November of 2017.

Cannabis alone won’t put an end opioid-related morbidities and mortalities. However, the growing body of research supporting the medical use of cannabis as a potentially safer adjunct or substitute for prescription opioids in the treatment of chronic pain certainly creates an evidence-based rationale for governments, health care providers, and academic researchers to implement and assess these cannabis-based interventions, and to reconsider prescription guidelines and other policies that may actually be negatively impacting the health and welfare of critically and chronically ill Canadians.


This article is an excerpt from:

Lucas, P. (2017). Rationale for cannabis-based interventions in the opioid overdose crisis. Harm Reduction Journal, 14(1), 58.


Abrams, D. I., Couey, P.,, Shade, S. B.,  Kelly, M. E.,  & Benowitz, N. L. (2011). Cannabinoid-opioid interaction in chronic pain. Clinical Pharmacology and Therapeutics, 90(6), 844–51. doi:10.1038/clpt.2011.188.

Bachhuber, M. A., Salone, B., Cunningham, C. O., & Barry, C. L. (2014). Medical cannabis laws and opioid analgesic overdose mortality in the United States, 1999–2010. JAMA Internal Medicine, 19104, 1–6. doi:10.1001/jamainternmed.2014.4005.

Boehnke, K. F., Litinas, E. & Clauw, D. J. (2016). Medical cannabis use is associated with decreased opiate medication use in a retrospective cross-sectional survey of patients with chronic pain. The Journal of Pain, 17(6), 739–44. doi:10.1016/j.jpain.2016.03.002.

Bradford, A. C., & Bradford, W. D. (2016). Medical marijuana laws reduce prescription medication use in Medicare part D. Health Affairs, 35(7), 1230–36. doi:10.1377/hlthaff.2015.1661.

Cichewicz, D. L. (2004). Synergistic interactions between cannabinoid and opioid analgesics. Life Sciences, 74(11), 1317–24. doi:10.1016/j.lfs.2003.09.038.

Lucas, P., & Walsh, Z. (2017). Medical cannabis access, use, and substitution for prescription opioids and other substances: A survey of authorized medical cannabis patients. International Journal of Drug Policy, 42, 30–35. doi:10.1016/j.drugpo.2017.01.011.

Meuse, M. (2017, April 27). B.C. breaks record for daily overdose ambulance calls. CBC News.

Retrieved from

Raby, W. N., Carpenter, K. M., Rothenberg, J., Brooks, A. C., Jiang, H.,  Sullivan, M., … Nunes, E. V. (2009). Intermittent marijuana use is associated with improved retention in naltrexone treatment for opiate-dependence. The American Journal on Addictions / American Academy of Psychiatrists in Alcoholism and Addictions, 18(4), 301–8. doi:10.1080/10550490902927785.

Scavone, J. L., Sterling, R. C.,  Weinstein, S. P., & Van Bockstaele, E. J. (2013). Impact of cannabis use during stabilization on methadone maintenance treatment. American Journal on Addictions, 22(4), 344–51. doi:10.1111/j.1521-0391.2013.12044.x.

Walsh, Z., Callaway, R., Belle-Isle, L., Capler, R., Kay, R., Lucas, P., & Susan Holtzman, S. (2013). Cannabis for therapeutic purposes: Patient characteristics, access, and reasons for use. International Journal of Drug Policy, 24(6). 511–16. doi:10.1016/j.drugpo.2013.08.010.

Matt Meuse, April 27, 2017. B.C. breaks record for daily overdose ambulance calls. CBC News.

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