Research investigating how cannabis can be used to treat pain usually focuses on individual cannabinoids such as THC, CBD and CBN, with little attention paid to the role of medicinal role terpenes. However, in a recent study published in the journal PAIN, researchers found that terpenes, especially when combined with morphine, could be a safer, more effective treatment than morphine alone.
Terpenes are found in all plants, including cannabis, contributing towards the aroma plants emit. Most plants have two dominant terpenes. Cannabis is unique in this aspect as it contains 150 terpenes and many of them perform a dominant role.
Because of this scientists from the University of Arizona used a mouse model to test the efficacy of morphine in treating pain caused by chemotherapy, and compared the results to that of five different terpenes found in cannabis; alpha-humulene, beta-caryophyllene, beta-pinene, geraniol, and linalool.
Their results showed that individually the five terpenes performed better, or as well as morphine when administered via injections. When comparing different routes of terpene administration, injection, oral dosing and inhalation of vaporised pure terpenes, the study found that when terpenes were given orally or inhaled, the effects were significantly reduced or absent.
The scientists also found that when individual terpenes were administered in combination with morphine the effect it had at treating neurological pain caused by chemotherapy treatment exceeded that of morphine alone.
The researchers suggested terpenes could be a better overall therapy than morphine not only for their pain-fighting properties but also because they have a better side-effect profile. Morphine is well known to cause addiction, as well as other unwanted effects such as withdrawal symptoms.
In the study, none of the terpenes produced reward-associated behaviour after being administered, showing that they don’t have addictive properties. Alongside this terpenes showed less chance of causing adverse effects, suggesting that when used in clinical settings they would be unlikely to make patients feel unwell after use, or to cause overdose.
“That was really striking to us, but just because something relieves pain doesn’t necessarily mean it’s going to be a good therapy… We looked at other aspects of the terpenes, such as does this cause reward? Is this going to be addictive? Is it going to make you feel awful?… What we found was yes, terpenes do relieve pain, and they also have a pretty good side effect profile,” said Professor John Streicher from The University of Arizona.
“This brings up the idea that you could have a combination therapy, an opioid with a high level of terpene, that could actually make the pain relief better while blocking the addiction potential of opioids. That’s what we are looking at now.”
The data shows exciting prospects for the use of terpenes in combatting pain in a more safe and effective way, although as the study used a mouse model more research will have to be conducted.
