- The pain is attributable to one or more of the following conditions: osteoarthritis/osteoarthrosis; spondylosis; radiculopathy; diabetic peripheral neuropathy; post-herpetic neuralgia; chronic idiopathic axonal polyneuropathy; fibromyalgia; or pain of uncertain origin or idiopathic, as long as it has had and it is expected to have a chronic nature, even if with spontaneous fluctuations.