SCIENTISTS are launching a landmark study into drugs already prescribed for motor neurone disease, heart problems and asthma to halt the debilitating effects of multiple sclerosis (MS).

Researchers from Edinburgh University and University College London (UCL) will test whether medicines for the conditions could benefit certain people with MS.

Scotland has the highest prevalence of MS in the world, with around 10,500 people affected. It causes loss of mobility, muscle spasms, slurred speech and fatigue.

It is hoped the drugs will work on those who have secondary progressive multiple sclerosis, which is characterised by increasing disability, by protecting the nerves from damage.

The scientists believe the trial could revolutionise the way patients with MS are treated and, because the drugs are already licensed and known to be safe, it could shave years off the time usually needed before new treatments can be rolled out.

Dr Jeremy Chataway, consultant neurologist and lead researcher on the trial based at UCL, said: "While there are an increasing number of treatments for MS that can reduce the frequency or severity of MS relapses, there's nothing that can stop the rapid accumulation of disability in people with secondary progressive MS.

"It's a huge unmet need in the treatment of the condition and, despite many clinical trials, scientists have so far failed to find anything that works."

Dr Susan Kohlhaas, head of biomedical research at the MS Society, said: "People with MS have lived for years in the hope that one day we will find an effective treatment for secondary progressive MS. This trial, although still at an early stage, takes us one step closer to making that hope a reality."

MS is an autoimmune condition in which the immune system attacks the myelin, a protective sheath surrounding nerve fibres of the central nervous system.

Research suggests a combination of genetic and environmental factors cause MS and rates are consistently higher in northern hemisphere countries than in those which are close to the equator.

Two-thirds of people with relapsing remitting multiple sclerosis go on to develop secondary progressive MS within 15 years of their initial diagnosis, according to the Multiple Sclerosis Society.

The trial will test three drugs – amiloride, which is licensed to treat heart disease; ibudilast, which is used for asthma; and riluzole, prescribed for patients with motor neurone disease.

They will be tested against a placebo in 440 people chosen from 15 sites across Scotland and England. Patients will be monitored for two years using MRI scans and other tests.

Professor Siddharthan Chandran, clinical neurologist at Edinburgh University, said: "This is a landmark study that seeks to not only test three potential treatments but also showcase a new approach to clinical trials for progressive neurological conditions."

Edinburgh University has been at the forefront of research into MS and Harry Potter author JK Rowling donated millions of pounds to its work after her mother Anne died from complications caused by the condition.

As well as drug treatments, scientists there are also investigating stem-cell therapy which aims to reverse the effects of MS rather than just suppressing the immune system.