Because I couldn't tell any difference with my pain. I don't recall any problems. I'm only taking it now because of my internal vibrations. I've had them since 2019 and my neurologist thinks it's from an overactive central nervous system. When I told my pain management doctor about the Fycompa my neurologist wanted to put me on, a pediatric dose, I researched it and decided against it. He then told me it was similar to gabapentin and Lyrica so I started taking it again and so far the vibrations have stopped. I may have had 1 or 2 at a level 2 but nothing like they were. At a 10 they'd wake me and I thought one of my cats jumped on the bed but it was me vibrating. If the gabapentin can help with the nerve issues in my legs then that's a plus but I'm more concerned with the vibrations. I'd love to sleep past 3:00.