I have been taking 800-1600 mg's of gabapentin a day for neuropathy in hands and feet and described my doctor as idiopathic(no known reason). My symptoms too are worsening and it is my theory that my b12 is not absorbing resulting in low b12 values. b12 deficiency especially if other family members have had b12 deficiency can cause neuropathy. I was not aware of this but am in the process of research. Good luck.