Hello,
Yes, slurred speech can be a side effect of Topamax. One of the "common" side effects listed for it is "speech and language problems." You can find this and other information in this Topamax Profile. If this is from the Topamax, it may go away after a while. If it continues or becomes worse, or if you experience other troublesome side effects, please contact your doctor.
Good luck,
Teri