New York: A new drug that helps sufferers of multiple sclerosis to walk may soon be on the market.

The drug, known as Fampridine-SR, helps damaged nerves communicate with each other and may also be helpful in treating spinal injuries.

Although there are drugs that help relieve some MS symptoms there is nothing available that helps with the problems of mobility caused by the disease. The crippling disease is usually diagnosed between the ages of 20 and 40 and affects three times as many women as men.

The cause is unknown and doctors are not certain whether it is caused by a virus or the immune system. The early symptoms include tingling and extreme tiredness. In later stages patients are usually wheelchair bound and have problems with mobility and speech and sufferers have good and bad periods.

As well as drugs some patients have been able to use a cannabis-based drug called Sativex. The drug is a spray that is squirted into the mouth and contains two of the active ingredients in cannabis, tetrahydrocannabinol and cannabidiol. Stem cell treatment may also be a possibility.

The new twice a day mobility pill which is made by Acorda Therapeutics, is a slow-release tablet that lets tiny quantities of the active drug seep into the central nervous system over several hours. The latest trial results suggest it can have a dramatic impact.

More than 300 patients with walking disabilities were given either the active pill or a dummy one and then asked to complete a timed 25ft walk to test their speed and agility. The test was repeated over the course of the 14-week trial.

Results showed 35 per cent of those on Fampridine-SR showed improvements in walking, compared with just eight per cent in the placebo group.

Tests also revealed improvements in leg strength. However, patients on the drug reported more side-effects such as seizures, nausea and dizziness.

The drug works by stopping potassium leaking from cells. When myelin gets damaged, potassium can escape, weakening the electric current that helps to carry messages. The drug stops these leaks and helps electrical signals pass through areas of damage.