- Subjects with causes for their neuropathic pain other than that specified in the inclusion criteria [e.g. post-herpetic neuralgia, painful diabetic neuropathy, mononeuritis multiplex, central post-stroke pain, failed back surgery in relation to the presenting episode of radiculopathy, spinal abscess/infection/haematoma/malignancy, phantom limb pain, peripheral neuropathy due to alcoholism, malignancy, HIV, syphilis, drug abuse, vitamin B12 deficiency, hypothyroidism, liver disease, toxic exposure], pain associated with a substantial somatic pain component [e.g.non-neuropathic / musculoskeletal pain in lower limbs or other parts of the body apart from the back] or more than one cause or potential cause for pain symptoms or any concurrent rheumatic disease such as but not limited to fibromyalgia, rheumatoid arthritis or significant osteoarthritis. Any question regarding the acceptability of aetiology of the neuropathic pain should be discussed with the GSK medical monitor.