Neuropathic pain remains difficult to treat. Treatments with established efficacy in several neuropathic conditions include tricyclic antidepressants, gabapentin, pregabalin and strong opioids. Duloxetine and venlafaxine, both antidepressants, and tramadol, an opioid agonist, are also known to be effective in painful polyneuropathies, while lidocaine patches produce analgesic effects, mainly in postherpetic neuralgia. Studies show that pregabalin, gabapentin and duloxetine have positive effects that improve quality of life, and anxiety, depressive, and sleep disorders.