Cannabis has been consistently used to treat pain since the beginning of its medicinal history. Even today, the most common reported use of medical cannabis is for pain relief, and support for this is not only anecdotal, as there’s a large body of evidence supporting this claim. Although cannabis is helpful to many who suffer from pain, there are still many limitations to using it as a pain medication. The most obvious problem is that cannabis causes a well-known “high” feeling. This effect is not necessarily negative, yet it may not be ideal when attempting to relieve pain symptoms. Not only does cannabis get you “high” but it can reduce motor control, attention and can potentially cause memory problems, anxiety, confusion and even panic for some users. These side effects greatly limit the ability of cannabis to be used as a pain medication for many people. Many of the effects mentioned are caused by a compound called THC, which is short for Δ9-tetrahydrocannabinol. Thankfully, there are over 100 other substances in cannabis that are very promising for the development of better pain relief treatments.

One of these other substances is cannabidiol, or CBD (cannabis’ other main component) which has gained a lot of attention lately for its potential as a treatment for conditions like epilepsy, multiple sclerosis, anxiety and pain. CBD does not cause a “high” like THC making it a more realistic option as a pain reliever. Less well known is a compound called CBDA, or cannabidiolic acid, which is the precursor to CBD. This means that CBDA is found in the fresh cannabis plant and is converted to CBD after drying or heating of the plant. Scientists believe that this compound also has similar effects to CBD. So why would we be interested in this compound if we already know that CBD can reduce pain? Well, research shows that CBDA is a lot more potent than CBD. For example, CBDA is able to reduce nausea at a dose that is 100-1000 times smaller than an effective dose of CBD.

Because of the strength of CBDA in comparison to CBD, researchers in Dr. Linda Parker’s lab at the University of Guelph tested whether it could reduce pain caused by inflammation. They found that CBDA is able to reduce pain and swelling when given to rats. In fact, CBDA reduced pain and inflammation in rats at a dose that was much lower than that of CBD, indicating that this compound can be even more effective at relieving pain than CBD. 

It is well known in the science community that the two main molecules in cannabis – CBD and THC – can work together to produce some of the effects caused by cannabis. Because of this, another experiment was conducted to see if CBDA can work with THC to reduce pain. To study this, THC and CBDA were combined at very low doses that, when given alone, are not able to reduce pain. When combining these low doses of THC and CBDA, both pain and inflammation were reduced. This finding is exciting because as mentioned, the use of THC for pain management is not ideal because of its negative side effects but combining smaller amounts of this THC with other drugs like CBDA might be able to decrease its side effects while still taking advantage of its pain-relieving effects. 

The findings from this study are very promising for better understanding how different compounds in the cannabis plant can be used to alleviate pain. Many of the medications prescribed for pain today are opioids which have unwanted side effects and are highly addictive, contributing to the opioid epidemic currently happening in the United States. There is a great need to develop better and safer medication for the management of pain, and compounds from the cannabis plant may just be the solution.

Reference: “Effect of cannabidiolic acid and Δ9-tetrahydrocannabinol on carrageenan-induced hyperalgesia and edema in a rodent model of inflammatory pain”, Rock et al. (2018), Psychopharmacology 235(3259-3271).

Edited by Jennifer Sieben and Clara Boothby