Clemastine fumarate, an over-the-counter (OTC) antihistamine, was found to partially reverse vision damage in patients with multiple sclerosis (MS), according to a preliminary study that will be presented at the American Academy of Neurology’s 68th Annual Meeting. 

In MS, the immune system damages the myelin, which then causes damage along the nerves. Optic neuropathy is a common adverse event from the disease. Clemastine fumarate can be found in medications to treat symptoms of allergies and the common cold. Researchers from University of California San Francisco discovered that this ingredient could potentially aid in brain repair. 

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Ari Green, MD, study author, and colleagues conducted a 5-month study (n=50) in adults who had MS for about 5 years with mild disability. All patients showed stable chronic optic neuropathy. Vision tests were assessed at the beginning and end of the study. One test, a visual evoked potential, measured the time for signal transmission from the retina to the visual cortex. Study inclusion criteria were having a delay in transmission >118msec in at least 1 eye and having have evidence of sufficient nerve fibers to reinsulate. 

Patients were given clemastine fumarate or placebo for the first 3 months, then switched treatments for the second 2 months. Data showed transmission delays were reduced by an average of <2msec in each eye per patient among those who took clemastine fumarate. 

Dr. Green added that though the improvement seemed modest, this study was the first to show possible repair of the myelin in patients with chronic demyelination from MS. More research with greater sample sizes are needed before clemastine fumarate can be recommended for patients with MS. 

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