Chronic administration of ketamine for analgesia.

Use of the dissociative anesthetic ketamine in subanesthetic doses has demonstrated efficacy in neuropathic pain. This article reviews the scientific and clinical literature on ketamine. Mechanisms of both central and peripheral neuropathic pain are described. Studies of ketamine analgesia in postherpetic neuralgia, phantom pain, complex regional pain syndrome and cancer pain are reviewed. A range of administration methods for ketamine including neuroaxial administration are described.