Ahh....the ultimate question..."anything that doesn't cause weight gain..." I've been waiting for that magic medication as well. I've been on Topamax for going on 7 years, and it's not working anymore. So I've been researching every medication out there to find something else to replace it with. Problem being every single bipolar medication out there has a side effect of "increased appetite" and/or "weigh gain". I know if I see these side effects I'll stop taking the meds. I look forward to others responses and getting some ideas for any medications to replace the Topamax.
Good luck! I hope you can find something that will work for you!!