I took Gabapntin for four years and always felt there were side effects. I was always tired, I 'lost' my words during conversations, I forgot things and generally felt lethargic. I changed in January to Lyrica and I am a different person, I can actually speak clearly again and am not as tired.
Don't get me wrong Gabapentin does it's job but if you can get your doc to prescribe Lyrica it's much better( well for me) and you don't have to take as many of them.
Good luck with whatever meds you take, what works for one person doesn't work for someone else... X