Awhile ago an issue of splitting dosages came up & I mentioned I read somewhere that you shouldn't & on my pill bottle there are markings stating not to chew, split, crush. Someone said it was due to the bitterness.
The following is a link from mo3's article re:Topa where it states:
Topiramate tablets have a bitter taste and lose their effectiveness quickly when broken, so you should swallow them whole. Do not split, chew, or crush them.
I'm no pharmacist...but pass the FYI
MedlinePlus Drug Information: Topiramate