A Scottish doctor is raising money to fund his own drug trial, testing a treatment for heroin addicts on multiple sclerosis patients.

The pill, naltrexone, is available free on the NHS to substance abusers. It blocks the pleasurable effects of opioids and helps the battle against cravings.

However, growing numbers of MS sufferers report that, in low doses, the same medication relieves a number of their symptoms.

Many are paying to buy the treatment privately because it has not been licensed for use in small quantities against MS. While GPs will prescribe 50mg of the drug to heroin addicts, many are unwilling to prescribe 3 or 4mg to MS patients.

Now Glasgow GP Dr Tom Gilhooly, along with consultant neurologist from Tayside Dr Jonathan O'Riordan, have unveiled plans to conduct their own research on low-dose naltrexone (LDN).

It is hoped if they can provide good evidence the drug works in MS cases, that will lead to patients receiving the treatment on the NHS.

The LDN Research Trust, which was set up in England, has raised £9500 through charitable donations from patients to help pay for a trial and plans to support the Scottish project.

Dr Gilhooly also undertook a 28-mile sponsored mountain-bike ride yesterday to raise extra money for the charity. He said £50,000 was needed to fund the trial and he intended to apply to Scotland's Chief Scientist Office for further assistance.

Dr Gilhooly said: "I have seen with my own eyes in my own practice over the last three years the significant improvements in people who really do not have much in the way of options.

"Many of these patients have primary or secondary MS. I passionately feel that everyone with MS at least deserves a chance to try this. It does not work for everyone but in some people it works so well. It suffers because it is not a profitable drug."

He said the research would meet the required standards as a randomised, double-blind, placebo-controlled trial. The intention is to recruit 120 patients from Glasgow and Tayside and record improvements in a symptom of MS which can be measured - frequency of urination.

Linda Elsegood, who set up the research trust, said it would be a fantastic day when the trial began.

She said: "Doctors cannot open a book where it says in a low dose, naltrexone can be used for MS'. They have not got time to find out for themselves if it is going to make the person ill.

"If they are not confident about giving it, they say no. We hope the trial would change that situation.

"I think if you get some-thing in writing, if we can get it in a medical journal, there is that security of it saying in black and white it has been trialled, it is safe, and doctors will be more willing to prescribe it."

Dr Lee Dunster, head of research and information for the MS Society, said they wanted to see innovative, safe and effective therapies on the market. "The situation with LDN is there is a lot of anecdotal information out there and, clearly, we need to do the trials.

"The society has last year and this year received applications for funding LDN trials but when they are looked at the applications that have come in so far have fallen way below the standards in terms of numbers and methods used.

"There was an application which has come from Scotland, there was feedback given back to that group that submitted that. There were some key things that needed to be looked at."

Dr O'Riordan, director of the Tayside MS Research Unit, said it was difficult to set up trials and there were strict guidelines governing methods.

He also warned it was difficult to judge an MS treatment on the basis of anecdotes because patients naturally experienced flare-ups and periods of improvement.

However, he continued: "There does appear to be enough anecdotal evidence to suggest a clinical trial of some sort should be performed. If data is not obtained, we are left with the status quo. We do not know whether it works or not. People who benefit might have benefited anyway because they might have been in a good period. But if it works, then we are withholding it from patients."

Patient hails the 'return of freedom'

Then she would climb out of bed, sit for a few minutes, before walking stiffly to the bathroom. Taking a shower, she said, was like 10 rounds in a boxing ring and after drying she would have to lie down again.

"It's not like that now. It's not been like that for four years," she added.

In 2003, she began taking low dose naltrexone, a treatment used in larger quantities to treat heroin addicts, after reading about it on the internet. She learned that a New York doctor had experimented with the drug on patients, including MS sufferers.

The first difference Mrs McDevitt noticed was the numbness in her back reduced, then the stiffness and fatigue. It began to give her back some of the freedom which had been stolen by her illness.

Four years on, she said the treatment was still giving her a better quality of life. While she experiences some tougher days, she believes the drug is keeping symptoms at bay.

It costs her £25 a month to obtain the drug on a private prescription through her GP. She said recognition of the treatment's potential is growing in other countries and she believes it will be available on the NHS to MS patients in the future.

"It is definitely going to happen," she said. "I feel very confident about that."