Hospital doctors are to treat patients with cannabis in a world first for Greater Manchester.

Experts believe the drug can relieve pain by numbing muscles – and say it does not give users a 'high'.

It is the first time the drug has been used in a hospital anywhere in the world

Patients at North Manchester General and Fairfield in Bury have been prescribed Sativex – a medication derived from marijuana plants. They will spray the medication under their tongue up to ten times a day.

People who are terminally ill with cancer will intiially take part in the trial but  if successful, its use could be extended across the country and used as a painkiller for other conditions. Eight people have already been signed up, and 32 others will be recruited over the next two years.

The drug has been available on prescription in Britain as a treatment for Multiple Sclerosis since last summer – but it has not been used in hospitals before.

Sam Jole, senior research nurse at Pennine, the trust which runs North Manchester and Fairfield, has been involved in setting up the trials and identifying, recruiting and monitoring patients.

He said: “Research in palliative care, especially looking at new drug treatments is rare.

”The majority of cancer research is focused on curing disease. Palliative care is an under-researched medical speciality and the studies are genuinely ground-breaking. I’ve been a research nurse for years and have never come across anything like it.

“It is very important to point out that patients using the spray do not experience the euphoria associated with the illegal recreational use of cannabis. It has passed strict tests for quality, safety and efficacy and doctors are already prescribing it for Multiple Sclerosis patients."

Patients involved in the study will visit either North Manchester or Fairfield General for check-ups four times over a five-week period.

They will also be required to  to report their pain scores and usage of painkillers. Every evening over the phone.

Around half of them will be prescribed the active drug and the rest will receive a placebo.

The treatment was the world's first cannabis medicine to win regulatory clearance when it was approved in Canada in 2005. It was approved for use in Britain last June.

The drug, created by GW Pharmaceuticals,  is made from two cannabinoid substances found in the marijuana plant, THC and CBD. THC produces a high, but CBD counteracts it, and because Sativex is an oral spray, the drug is absorbed more slowly than if it was smoked so scientists say it is impossible to 'get high' from the treatment.

Dr Iain Lawrie, consultant and honorary clinical senior lecturer in palliative medicine at North Manchester General Hospital, said: “This study is an exciting development in the field of cancer pain management. Initial clinical observations suggest that Sativex will have an important role to play in this complex area of palliative care.”