Valproic Acid AKA Depakote, is an anti-seizure medicine. It can be effective in controlling manic episodes in bipolar disorder and can be effective in managing migraine pain in certain patients. I would recommend trying it.
Side effects can include mood changes, weight gain, etc. I found it to be tiring and ineffective, but every person is different. Another interesting side effect is pancreatitis. Very rare, but if you have any weird left upper quadrant severe stomach pains, start weening off the med and call your GP immediately. What else have you tried other than the topamax?
Hope this helps.