Medicinal Cannabis and Chronic Pain

Cannabis has been used for  centuries both as a recreational drug for its mind altering properties, and as a medicine for its ability to relieve various physical or mental complaints (Bostwick, 2012). However, until half a century ago, very little was known about how cannabis works in the human body and brain.

We now know that humans and other animals have an endocannabinoid system that extends throughout the body. This system encompasses receptors that bind to both external cannabinoids and endocannabinoids made by our own bodies.  (Wilson and Nicoll, 2002, Howlett et al, 2004). The cannabinoids produced internally are released on demand and help to regulate numerous physiological processes, including pain (Russo and Hohmann, 2013).

The cannabis plant produces cannabinoids that are similar to the endocannabinoids produced by our own bodies. Research has demonstrated that cannabinoids from plants can alleviate pain that does not respond to traditional treatments (Mackie, 2006, Russo and Hohmann, 2013, Watson et al, 2000, Ben Amar, 2006).

Cannabinoids External to Our Bodies Can Help Manage Pain

There are more than 100 naturally occurring chemical compounds, called cannabinoids, produced by the cannabis plant, but only two have been well characterized pharmacologically: Delta 9-tetrahydrocannabinol, known as THC, and cannabidiol, or CBD.

Cannabinoids produced by plants have been found to be clinically useful for chronic pain management, and work by directly or indirectly modulating cannabinoid activity.

THC and CBD have several therapeutic indications, including the treatment of chronic pain (Aggarwal, 2013, Lynch et al, 2011; Russo, 2008) and intractable pain related to:

THC is also the agent responsible for the psychoactive effects of cannabis. These effects - sought by recreational users – are the most frequently mentioned reason for discontinuation of medicinal cannabis use among patients, since they compromise the level of functionality in a patient’s everyday life.

However, CBD has the unique ability to inhibit THC’s psychoactive effects, minimizing THC side effects such as euphoria, memory loss, paranoia, and anxiety (Bhattacharya et al, 2010, Russo, 2011, McPartland and Russo, 2001). Medicinal cannabis is best tolerated when high levels of CBD are present.

Medicinal Cannabis Safety and Potential Side Effects

Cannabis is a relatively safe medication when compared to many of the prescription drugs widely used to control chronic or intractable pain.  Unlike opioid-based medications such as oxycodone (Oxycontin) and hydrocodone (Vicodin), cannabis will not result in an overdose death. This does not mean, however, that there are no risks:

Routes of Administration

Cannabis can be smoked or vaporized; ingested in food or beverages; absorbed sublingually; or used topically. How cannabis is administered determines how quickly therapeutic effects will be felt and how long the effects will last. More information about the routes of administration can be found in the brochure Medicinal Cannabis & Chronic Pain: Information for Patients.

Medicinal Cannabis in Washington State: What is the Law?

In Washington State, clinicians are allowed to recommend the use of medicinal cannabis. [Washington State RCW 69.51a]. As of July 1, 2016, rules stemming from the Cannabis Patient Protection Act have been implemented. Visit the Washington State Department of Health's Medical Marijuana page to learn more about the CPPA and associated elements, such as the authorization database, medical marijuana consultant, recognition card, authorization form, and more.

Where to Learn More


This information adapted with permission from the National Cannabis Prevention and Information Centre in Australia.