Peripheral neuropathy, often shortened to neuropathy, is a general term describing disease affecting the peripheral nerves, meaning nerves beyond the brain and spinal cord. Damage to peripheral nerves may impair sensation, movement, gland, or organ function depending on which nerves are affected; in other words, neuropathy affecting motor, sensory, or autonomic nerves result in different symptoms. More than one type of nerve may be affected simultaneously. Peripheral neuropathy may be acute (with sudden onset, rapid progress) or chronic (symptoms begin subtly and progress slowly), and may be reversible or permanent. Common causes include systemic diseases (such as diabetes or leprosy), hyperglycemia-induced glycation, vitamin deficiency, medication (e.g., chemotherapy, or commonly prescribed antibiotics including metronidazole and the fluoroquinolone class of antibiotics (such as ciprofloxacin, levofloxacin, moxifloxacin)), traumatic injury, ischemia, radiation therapy, excessive alcohol consumption, immune system disease, celiac disease, non-celiac gluten sensitivity, or viral infection. It can also be genetic (present from birth) or idiopathic (no known cause). In conventional medical usage, the word neuropathy (neuro-, "nervous system" and -pathy, "disease of") without modifier usually means peripheral neuropathy. Neuropathy affecting just one nerve is called "mononeuropathy" and neuropathy involving nerves in roughly the same areas on both sides of the body is called "symmetrical polyneuropathy" or simply "polyneuropathy".
As is revealed in many of the Cochrane systematic reviews listed below, studies of these medications for the treatment of neuropathic pain are often methodologically flawed and the evidence is potentially subject to major bias. In general, the evidence does not support the usage of antiepileptic and antidepressant medications for the treatment of neuropathic pain. Better designed clinical trials and further review from non-biased third parties are necessary to gauge just how useful for patients these medications truly are. Reviews of these systematic reviews are also necessary to assess for their failings. It is also often the case that the aforementioned medications are prescribed for neuropathic pain conditions for which they had not been explicitly tested on or for which controlled research is severely lacking; or even for which evidence suggests that these medications are not effective. The NHS for example explicitly state that amitriptyline and gabapentin can be used for treating the pain of sciatica. This is despite both the lack of high quality evidence that demonstrates efficacy of these medications for that symptom, and also the prominence of generally moderate to high quality evidence that reveals that antiepileptics in specific, including gabapentin, demonstrate no efficacy in treating it. Antidepressants
In general, according to Cochranes systematic reviews, antidepressants have shown to either be ineffective for the treatment of neuropathic pain or the evidence available is inconclusive.