Many diseases are associated with "neuropathic pain", which is not usually manageable with common analgesics, such as NSAIDs and acetaminophen. Calcium ion channel α2δ ligands, serotonin-noradrenaline reuptake inhibitors, and tricyclic antidepressants have been used as first-line drugs. If there are no improvements after using these drugs for a while, vaccinia virus inoculation of rabbit inflammatory skin extract, tramadol, and eventually opioid analgesics, may be considered.