A drug commonly taken to prevent epilepsy seizures could be used to protect people from an eye condition that is often associated with multiple sclerosis (MS), research has found.
Optic neuritis causes the nerves carrying information from the eye to the brain to become damaged and inflamed and can result in sudden total or partial blindness, foggy or blackened vision and pain. Around half of people with MS will experience it.
A clinical trial at University College London tested 86 people showing early symptoms of acute optic neuritis.
They found the group that took the epilepsy drug phenytoin for three months had 30% less damage to the nerve fibre layer compared to those who had been given a placebo.
There are more than 100,000 people living with MS in the UK but there is not currently a cure and although there are some treatments available to slow the progression of disability, they are not suitable for everyone.
The neurological condition sees the immune system attack myelin, a substance surrounding the nerves, which leads to delay and confusion in messages sent from the brain and spinal cord to parts of the body. It affects almost three times as many women as men and is unpredictable and can leave people unable to see or move.
Dr Raj Kapoor, of University College London Hospital, said: "About half of people with MS experience acute optic neuritis at some point in their life.
"These are promising results and, if our findings are confirmed by larger studies, could lead to a new treatment that protects nerves from the damage caused in both optic neuritis and throughout the central nervous system in MS."
Dr Emma Gray, head of biomedical research at the MS Society, said: "We're really proud to have co-funded this trial which is the result of many years of underpinning research by Dr Kapoor and his team. Studying the optic nerve gives us a window to the brain so we can get an idea about how a drug like phenytoin could protect nerve cells.
"Our goal is to ensure people with MS have access to effective treatments including treatments which can slow, stop or reverse the accumulation of disability and this trial takes us one step closer to that goal."