I have been on Gabapentin for 8 years (no weight gain or other side effects). It has put the pain I have and temperature intolerance well controlled, provided it I stay on an even dosage schedule. I am very happy with how it has helped me and pain has never been anything unmanageable. Several years ago, perhaps when Pregabalin started being a prevalent prescription, my Neurologist then suggestion we add that to my regimen. Since I really try to keep medications as low as possible, I asked what additional benefit or improvements Pregabalin would give me - he hesitated and admitted that since I was doing well with Gabapentin alone, he couldn't see what any improvements Pregabalin had to offer me. So we didn't do it, saved me the extra pill and all the adjustments that come with it. I think it all depends on individual needs and reactions to taking the meds, and trial & error to find what works for you.