UK pain experts say their “significant” and “encouraging” findings could be a breakthrough.
They have discovered that a synthetically-produced chemical compound which works like the illegal drug to relieve pain could be developed as a potential treatment.
The artificial compound could also reduce joint inflammation, according to new research at the Arthritis Research UK Pain Centre at the University of Nottingham.
It could be five to 10 years before a pill is available for patients.
But creating a drug which tackles pain long term without side effects would revolutionise the treatment of osteoarthritis.
Professor David Walsh, director of the centre, said: “The results are quite encouraging. There is the potential that this would be a completely new class of painkiller that would have benefits additional and different to painkillers already on the market. For a lot of patients, the drugs we have at present are just not good enough.”
Osteoarthritis affects eight million people the UK and occurs when the cartilage at the ends of bones wears away, causing joint pain and stiffness. It is a major cause of disability.
Current treatment is limited to pain relief, exercise, physiotherapy weight-loss and joint replacement. There are currently no drugs that slow down its progression.
What painkillers are available, such as opiates, can have dangerous side effects or can soon stop working.
But the Nottingham researchers, led by Professor Victoria Chapman, have shown that targeting a molecule involved in the body’s natural pain-sensing pathways in the spinal cord, called cannabinoid receptor2 (CB2), can also reduce osteoarthritis pain in animals.
Cannabis contains a number of natural chemicals called cannabinoids that can act as pain relievers. Their use is limited due to psychological side effects.
But the compound used in the study, called JWH133, is made in a laboratory and is not derived from the cannabis plant.
The research, published in the online journal Public Library of Science ONE, has shown that the CB2 receptor is present in human spinal cord tissue. Scientists see this as evidence JWH133 may combat osteoarthritis pain in humans.
Professor Alan Silman, medical director of Arthritis Research UK, said: “Millions of people are living with severe, debilitating pain and better relief is urgently needed.
“This research does not support the use of recreational cannabis use. What it does suggest is that there is potential to develop a synthetic drug that mimics the behaviour of cannabinoid receptors without serious side effects.”