Hi Linda,
I think we've been down this road before, but...
once more with FEELING!
Those drugs can be a polarizing topic - particularly the topomax. Weight loss? Maybe (like weight gain is a maybe with neurontin). With topomax, I'm more concerned about the risk of renal stones and permanent side effects. Nobody really knows how any of these drugs will affect them personally without giving them a try, and more important than weight loss/gain is how well they work for controlling your PAIN - that is, and should be, your primary concern. It doesn't matter which one you try first (most doctors will start with neurontin, then topomax, then Lyrica, but that's partly for insurance reasons - neurontin has been around forever, then topomax, and Lyrica is most expensive because it's still under patent).
If one doesn't work, or the side effects are intolerable, you can back off of it and try another. Please don't get hung up on this weight issue or other "maybes" until they become facts. Be concerned with pain management.
Weight loss - that's really a separate and distinct issue. I'm still doin' the intractable pain diet from Dr. Tennant, and despite a slight backslide (my fault) it's still working, and better still, I'm FEELING better when I'm on it. Less pain - more energy - better mood.
Have you tried sleeping with a pillow between your knees?
Doc