Hello, I m sorry to hear you ve been having some hair loss while on primidone. It is always a good idea to think of medication side effects when we have a change in our body like yours. In your case, hair loss is not reported as a side effect of primidone, and I have never heard of it causing this problem. While it s always possible your body is reacting in a way that hasn t been known before, I would investigate other causes first. You primary care doctor or a dermatologist can examine your hair and hopefully figure out what the cause is. Only if you cannot find a clear cause would I consider stopping the primidone to see if that helps, but I would be surprised if that is it. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Aaron Branch, General & Family Physician