Assessment of Clemastine Fumarate as a Remyelinating Agent in Acute Optic Neuritis (ReCOVER)

This trial is studying whether a medication called clemastine fumarate — an old antihistamine — can help repair the protective covering of nerve fibers (called myelin) in people who have just had an episode of optic neuritis, which is inflammation of the eye's optic nerve often seen in early multiple sclerosis. **You may be eligible if...** - You have been diagnosed with or are suspected of having acute optic neuritis (sudden vision problems due to nerve inflammation) within the past 3 weeks - You are using appropriate contraception if you are a woman who could become pregnant - You are able to understand and sign the informed consent form **You may NOT be eligible if...** - You have other significant eye diseases (such as glaucoma, severe nearsightedness, or macular degeneration) - You have no light perception in the affected eye - You have inflammation in both eyes at the same time - You have a history of significant heart rhythm problems or cancer - You have had thoughts of suicide or self-harm in the past 6 months - You are pregnant, breastfeeding, or planning to become pregnant - You have a history of drug or alcohol abuse in the past year - Your kidney or liver function tests are significantly abnormal - You have untreated vitamin B12 deficiency or thyroid problems Talk to your doctor to see if this trial is right for you.