The increasing role of cannabinoids in pain relief

Once forgotten, cannabinoids and their medicinal benefits have recently been thrust back into the spotlight, in particular for their abilities to relieve often otherwise untreatable pain. 

Cannabinoids are also much safer than the standard opioid drugs, which have side effects ranging from constipation to hormone dysregulation and death, often by respiratory suppression. 

In fact, cannabinoids may be 10 times more powerful for pain relief than morphine in the wide dynamic range neurons, meaning they could also be more effective. 

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Paul Benhaim

Cannabidiol, or CBD, is the primary non-psychoactive phytochemical that cannabis is known for. Like the psychoactive THC, CBD also possesses pain-relieving properties. 

Unlike THC, however, CBD is able to act on a type of pain receptor that is responsible for painful burning sensations, such as in inflammation. This is most likely by working as a counter-irritant, much like capsaicin in chilli. 

CBD can also stop pain indirectly through its anti-inflammatory effects, such as its ability to inhibit tumour necrosis factor-alpha (TNF-alpha), which is involved in rheumatoid arthritis and multiple sclerosis. 

It is also a powerful antioxidant, stronger than vitamins C and E, along with other neuro-protective abilities. Therefore, CBD may help to prevent and treat neuropathy, a painful condition where nerves are damaged 

Additionally, there are other cannabinoids with pain relieving properties. Cannabichromene (CBC) is the third most prevalent cannabinoid, and although it is weaker than THC, it does possess analgesic and anti-inflammatory abilities. 

Cannabigerol (CBG) has some affinity for CB1 and CB2 receptors, like THC and CBD, but also has powerful antispasmodic abilities because it can inhibit reuptake of the neurotransmitter GABA more than the two main cannabinoids. 

CBG also has stronger analgesic and anti-inflammatory properties than THC, able to block the lipooxygenase inflammatory pathway and reduce swelling. Increasing GABA levels is another mechanism that promotes pain relief, as many neurons in the spinal cord regions responsible for pain transmission are responsive to GABA, which is an inhibitory neurotransmitter. 

Besides cannabinoids, there are also several terpenoids and flavonoids present in cannabis that may have additive or synergistic effects in regards to pain relief. One of these, myrcene, appears to be an opioid-like analgesic.

Beta-caryophyllene acts on CB2 receptors as well as being anti-inflammatory on the PGE1 pathway, and protective towards the stomach lining. Alpha-pinene can also inhibit PGE-1, while the commonly found linalool shows local anaesthetic potential. Like CBD, the flavonoid apigenin inhibits TNF-alpha, while cannflavin A, which is unique to cannabis, may inhibit the PGE2 inflammatory pathway at a potency thirty times greater than aspirin. 

In conclusion, cannabinoids present a safe, and likely more effective, alternative to pain relief than currently available pharmaceutical and opium-based drugs. 

However, whole plant extracts may be superior to isolates of major cannabinoids, as even “minor” phytochemicals can assist in pain reduction to create a synergistic effect. 

Extracts from low-THC strains may be superior again to many common drug strains, as these are often low in CBD and other phytochemicals.

  • Paul Benhaim is chief executive of Hemp Foods Australia and Elixinol . He developed the first hemp seed snack bar for the European market, has written a number of books on hemp, and holds the only licence exemption from the Australian government to harvest the leaves and flowers of the hemp plant and turn them into Australian-made CBD extracts.