A drug which is normally used to treat heroin addiction can deliver "life-changing" results for a range of medical conditions, sparking calls for it to be offered more widely to patients.

A drug which is normally used to treat heroin addiction can deliver "life-changing" results for a range of medical conditions, sparking calls for it to be offered more widely to patients.

Medical experts claim that low-dose naltrexone (LDN) has been used successfully for people with a variety of conditions which affect the immune system, including multiple sclerosis, Crohn's disease and chronic fatigue syndrome.

At the first European conference into the drug which was initially prescribed in larger doses to block the effects of heroin use, speakers from around the world, including America and Israel, will hear results of trials into the drug and will call on GPs and other health professionals to prescribe it more widely.

Dr Tom Gilhooly, who is organising the conference in Glasgow, has around 200 patients at his clinic in Rutherglen, who are currently receiving LDN and he said he had recorded "a lot of success" in those who had taken the drug.

"It is a very interesting drug," he said. "It has very few drawbacks and it is very effective. If you find a drug that is successful, isn't toxic and can treat conditions that are normally difficult to treat it is a real find.

"We have used LDN to treat many different autoimmune diseases over the past five years and have seen life-changing results for patients. LDN treatment can aid a better quality of life for both long-term sufferers and for those newly diagnosed."

LDN, which appears to boost the production of endorphins in the body and stimulate the immune system, was first prescribed in doses of between 50mg and 150mg for heroin addicts.

It has since been used in doses of between 1mg and around 4.5mg to treat patients with multiple sclerosis and other conditions affecting the immune system.

It is given in a liquid form and patients currently tend to pay privately for the drug, which costs around £15 a month.

Dr Gilhooly said that around half of his patients who receive LDN had been prescribed it for chronic fatigue syndrome and fibromyalgia, a similar condition in with patients suffer from fatigue and chronic pain in their muscles.

Dr Gilhooly said: "We have used it for both with great success. I have been treating chronic fatigue syndrome for years but we have been incredibly limited in treatments. To find something like this that is working is great for the patients.

"Now that we know the drug we are looking at what other immune-related conditions we can try it on."

At the conference, which will be held at the Western Lecture Theatre at Glasgow University today, Dr Gilhooly will discuss the findings of a pilot trial from Stanford University on patients with fibromyalgia.

In six out of 10 patients LDN was "significantly better" than a placebo at reducing daily pain, fatigue and stress related to the condition.

Other symptoms, such as sleep problems, gastrointestinal complaints and headaches were also alleviated. No serious side-effects were reported.

Senior author Sean Mackey, associate professor of anesthesia and chief of the pain management division at Stanford University Medical Centre, said: "Patients' reactions were really quite profound. Some people decided to come off other medications. Some people went back to work really improving their quality of life."

Dr Mackey added that although he was "excited" by the preliminary results, more in-depth research would be carried out to establish the true impact of the drug on patients with fibromyalgia.

Dr Gilhooly said that he also hoped that research could be carried out in Scotland.

"Scotland is one of the places which is a hot area for LDN prescribing and research and we are hoping to carry out a lot of research in the future," he said.

Case Study: I'm feeling positive and no longer drained

AS a PE teacher, Christine Fowler had always enjoyed being active. But when she developed chronic fatigue syndrome nine years ago, it became an effort simply to get up in the morning.

"It was an all over weakness," she said. "I had a lot of pain in my legs and arms. I would be sitting on the sofa looking out of my front room, not able to do anything."

Mrs Fowler, 49, from Hogganfield, Glasgow, was forced to take long periods off work. After starting on a gradual exercise programme she was able to return to work but said she was still "only operating at 50%" and had to go to bed as soon as she returned from school.

In October she was forced to take another six weeks off work and Dr Tom Gilhooly suggested she try low-dose naltrexone to alleviate her symptoms.

She began taking 1mg every day, returned to work at the beginning of January and has not been off since.

Mrs Fowler, who has four children, said: "It has allowed me to operate at a much higher level on a day to day basis and be much more positive about everything. I'm not drained of energy.

"In the past even when I did mange to do something one day, the repercussions the next day would mean I was drained and sore. That is easing off."

She is now able to play a more active role at work. "In the past I wouldn't be physically able to do the things I wished to, even simple things like being able to demonstrate a headstand."

She has also played the odd game of badminton and is now hoping to take part in the Women's 10k next month, walking the course in the south side of Glasgow.

"Chronic fatigue syndrome drags you down," she said. "I'm now able to do things again. LDN has had a positive effect on me."