A Compound Found in Cannabis Could Make Opioids Safer

By Pat Anson, PNN Editor

What gives the cannabis sativa plant it’s pain-relieving properties?

Most people will tell you it’s cannabidiol (CBD) and/or tetrahydrocannabinol (THC), the two most well-known chemical compounds found in cannabis.  

But researchers at University of Arizona Health Sciences say terpenes -- aromatic compounds that give cannabis its distinctive “skunky” smell – have analgesic effects as well. In fact, in a new study published in the journal PAIN, they report that cannabis terpenes are just as effective as morphine in reducing neuropathic pain in laboratory animals.

“A question that we’ve been very interested in is could terpenes be used to manage chronic pain?” lead researcher John Streicher, PhD, a Pharmacology Professor at UA’s College of Medicine in Tucson, said in a press release. “What we found is that terpenes are really good at relieving a specific type of chronic pain with side effects that are low and manageable.”

Terpenes are found in all plants and are the main component of essential oils. Terpenes give lavender, sage and eucalyptus oils their distinctive smells, which are used to promote relaxation or even reduce pain and inflammation. In nature, terpenes help plants attract pollinators such as bees or to protect themselves from predators.

Most plants have only two dominant terpenes, but cannabis has up to 150 terpenes. Streicher and his colleagues tested five of the cannabis terpenes by injecting them into mice with chemotherapy-induced neuropathic pain.

They found that each of the five terpenes reduced nerve pain significantly, at levels similar to or even better than morphine. And when combined with morphine, the analgesic effects were enhanced even further.

Perhaps the most striking discovery is that the mice showed no signs of euphoria or “liking” terpenes – a sign that they may not have abuse potential.

“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?” Streicher said. “What we found was yes, terpenes do relieve pain, and they also have a pretty good side effect profile.”

In addition to injections, researchers also administered terpenes to the mice orally and through inhalation from a vaporizer. The results were the same. The mice had significant pain relief with no side effects or signs of addiction.

More research is needed, but some cannabis companies are already incorporating terpenes into their products. Lemon Kush, for example, is a marijuana strain that contains limonene, a terpene that smells like lemon, while the hybrid Blue Dream has a terpene that’s also found in blueberries.

“A lot of people vape or smoke terpenes as part of cannabis extracts that are available commercially in states where cannabis use is legal,” Streicher said “We were surprised to find that the inhalation route didn’t have an impact in this study, because there are a lot of at least anecdotal reports saying that you can get the effects of terpenes whether taken orally or inhaled.”

The next step for Streicher and his research team is to study whether terpenes can block the abuse potential of opioids, while at the same time enhancing their analgesic effects.

“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,” Streicher said.

Terpenes Make Cannabis More Effective as Pain Reliever

By Pat Anson, PNN Editor

A new study may help explain what makes cannabis effective as a pain reliever. It’s not just cannabinoids like cannabidiol (CBD) or tetrahydrocannabinol (THC), but terpenes -- the aromatic compounds that give cannabis its distinctive “skunky” smell. The finding could lead to new ways to boost the potency of cannabis, opioids and other pain-relieving drugs without increasing the dosage.

In experiments on laboratory rodents, scientists at the University of Arizona Health Sciences found that Cannabis terpenes, when used alone, mimic the effects of cannabinoids, including a reduction in pain sensation. When terpenes were combined with a synthetic cannabinoid, the pain-relieving effects were amplified – an “entourage effect” – that reduced pain levels without an increase in euphoria and other side effects.

"A lot of people are taking cannabis and cannabinoids for pain," said lead researcher John Streicher, PhD, a member of the UArizona Health Sciences Comprehensive Pain and Addiction Center and associate professor of pharmacology at the College of Medicine-Tucson.

"We're interested in the concept of the entourage effect, with the idea being that maybe we can boost the modest pain-relieving efficacy of THC and not boost the psychoactive side effects, so you could have a better therapeutic."

Terpenes are found in many plants and are the main component in essential oils. The terpene linalool gives lavender its distinctive floral scent, while citrus trees get their smell from the terpene limonene. Plants create terpenes to lure pollinators, such as birds and insects, and to protect themselves from predators.

Streicher and his colleagues focused on four Cannabis terpenes: alpha-humulene, geraniol, linalool and beta-pinene. They evaluated each terpene alone and in combination with a synthetic cannabinoid that stimulates the body's natural cannabinoid receptors.

In laboratory experiments, researchers found that all four terpenes activated a cannabinoid receptor in the brain, just like THC. The behavioral studies in mice also revealed the terpenes lowered pain sensitivity, reduced pain sensation, lowered body temperature, and reduced movement and catalepsy, a freezing behavior related to the psychoactive effects of cannabinoids.

When terpenes were combined with the synthetic cannabinoid, researchers saw a greater reduction in pain sensation -- demonstrating a terpene/cannabinoid interaction in controlling pain.

"It was unexpected, in a way," said Streicher. "It was our initial hypothesis, but we didn't necessarily expect terpenes, these simple compounds that are found in multiple plants, to produce cannabinoid-like effects."

The study findings were recently published in the journal Scientific Reports. Streicher and his research team still need to confirm if terpenes have an entourage effect when combined with THC and other naturally occurring cannabinoids. Their long-term goal is to develop a dose-reduction strategy that uses terpenes in combination with cannabinoids or opioids to achieve the same levels of pain relief with fewer side effects.

Although the therapeutic benefits of terpenes are not well understood, some cannabis companies are already incorporating them into their products. Lemon Kush, for example, is a hybrid marijuana strain that contains limonene, while the hybrid Blue Dream has a terpene found in blueberries. Terpenes are also being added to chocolate, beverages and many other consumer products.