I too am on Topomax and have found it to be a great substitute for gabipentin and lyrica, both of which had intollerable side effects for me.

Remember everyone reacts to medicines diffrently, for me the Topomax works very well three ways..

1) It controls the brain cramps I was getting (felt like a tightning vice).
2) It controls alot of the stabby jabby pains and make life way more tollerable.
3) It is helping me loose some of the weight I have gained in the last 4 years.

I have not noticed any hair loss, and I consider the weight loss an asset (for the time being anyway) There has been no sign of diareah.. constipation has been my companion since getting RSD. Nausia.. I had that before the topomax and the only thing that helps me with that is medicinal MJ.