Lack of evidence supporting medicinal cannabis benefits for arthritis sufferers - research

Some arthritis sufferers claim cannabis products provide them the most effective pain relief, but new research says there isn't enough scientific evidence to show it's safe or effective.

One in six New Zealanders has arthritis and Arthritis NZ's Francesca Holloway says pain is one of the biggest issues.

Medicinal cannabis is now available with a prescription from your doctor and anecdotally, some say their most effective source of pain relief comes from cannabis products or medicinal cannabis.

"There's certainly interest in it," Ms Holloway told 1 NEWS.

"We have a number of consumers who expressed interest or have used [it] themselves."

But scientific proof is another thing. There have been a number of trials on mice but human trials are scarce and not encouraging.

"We found two trials that looked at cannabis based products in arthritis... and there was no evidence really from either of those trials that they made a difference in the arthritis condition," the Medical Research Institute of NZ's Dr Irene Braithwaite says.

The independent New Zealand research was prompted by the expectation doctors would increasingly be asked by patients to prescribe medicinal cannabis.

One of the trials the researchers looked at found it was no more effective dealing with arthritis than a standard anti-inflammatory.

New Kiwi company Helius Therapeutics is devoted to developing medicinal cannabis, with some small crops just the beginning of what will be a large scale production and manufacturing operation.

Chief executive Paul Manning says there's a need for increased clinical studies around the treatment.

"Here in New Zealand, we have actually committed to undertaking clinical trials in this very area," he says.

"We really do believe that there's significant potential and we want to prove that through clinical trials."

Trials that can't come soon enough for people with arthritis.

"There's no silver bullet when it comes to managing arthritis pain," Ms Holloway says.

Five human trials are underway around the world, but it could be four or five years before any are completed here.

"It's really a question of whether more evidence will be developed in the future that will give us the confidence to prescribe," Dr Braithwaite says.