I've been taking gabapentin for about 1 yr, not for fibro though. It has done wonders to relieve the muscle spasms in my neck & shoulder areas. I never noticed any side effects but everyone is different. My doctor also increased my dosage when I had a shingles outbreak. Gabapentin (Neurontin) is for nerve pain. Hope it helps and you get some relief from it.
DDD, osteoarthritis, fusion surgeries C-5/7 & L-4/5 both in 2006, torn meniscus left knee 2000 & 2002, buldging disc L-2/3