Pain forum. Part 2. Neuropathic pain.

Neuropathic pain is often a reason for an unfavourable response to morphine or other opioids in treating cancer pain. This type of pain is difficult to manage and may co-exist with nociceptive cancer pain. There is still a potential for opioid responsiveness, although the doses needed will be higher, and adjuvant drug therapies are best employed concurrently with opioid drugs. Adjuvant drugs used are the antidepressants, anticonvulsants, including benzodiazepines, corticosteroids and neurolepts. Less commonly, agents such as baclofen and clonidine, and sympatholytic drugs such as prazosin can be employed for sympathetically maintained neuropathic pain (discussed in Part 3). The type of agent selected will depend on the natural history of the disease process, as well as a description of the pain--the lancinating pains tending to respond better to anticonvulsants. Non invasive neurostimulatory approaches such as transcutaneous electrical nerve stimulation (TENS) may be useful in management, and a few patients may require an invasive procedure such as dorsal column stimulation.