Gabapentin
"I have diabetic neuropathy and fibromyalgia.  I could barely walk when I started taking this medicine 4 years ago.  The first two weeks were difficult as I felt like I was "high" but that wore off.  I am now up to max dose 1200mg 3x per day.  If I miss a dose the pain is INTENSE. I try not to ever do that.  It makes me a bit chatty so we've affectionately nicknamed it "gabby"."