RESUMO
Damage to the somatosensory nervous system poses a risk for the development of neuropathic pain. Such an injury to the nervous system results in a series of neurobiological events resulting in sensitization of both the peripheral and central nervous system. The symptoms include continuous background pain (often burning or crushing in nature) and spasmodic pain (shooting, stabbing or "electrical"). The diagnosis of neuropathic pain is based primarily on the history and physical examination finding. Although monotherapy is the ideal approach, rational polypharmacy is often pragmatically used. Several classes of drugs are moderately effective, but complete or near-complete relief is unlikely. Antidepressants and anticonvulsants are most commonly used. Opioid analgesics can provide some relief but are less effective than for nociceptive pain; adverse effects may prevent adequate analgesia. Topical drugs and a lidocaine-containing patch may be effective for peripheral syndromes. Sympathetic blockade is usually ineffective except for some patients with complex regional pain syndrome.