Articles: neuralgia.
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Reg Anesth Pain Med · Jul 1999
Randomized Controlled Trial Comparative Study Clinical TrialComparative therapeutic evaluation of intrathecal versus epidural methylprednisolone for long-term analgesia in patients with intractable postherpetic neuralgia.
BACKGROUND AND OBJECTIVES The goal of this study was to evaluate the analgesic effects of intrathecal versus epidural methylprednisolone acetate (MPA) in patients with intractable postherpetic neuralgia (PHN). ⋯ Our results suggest the effectiveness of intrathecal as compared to epidural MPA for relieving the pain and allodynia associated with PHN. Also, our findings, together with the decrease in IL-8, may indicate that intrathecal MPA improves analgesia by decreasing an ongoing inflammatory reaction in the CSF.
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J Pain Symptom Manage · Jul 1999
Case ReportsAnalgesic effect of oral ketamine in chronic neuropathic pain of spinal origin: a case report.
Ketamine is an injectable anesthetic induction agent that has been reported to have analgesic activity in pain from a variety of mechanisms, but predominantly in neuralgic and dysesthetic neuropathic pain. In this case report we illustrate the effectiveness of ketamine in a patient with neuropathic pain resulting from cauda equina trauma. Among the issues addressed are the role of pretreatment with haloperidol to prevent ketamine-induced psychomimetic effects, the potential for fewer side effects and a need for lower doses when ketamine is administered orally, and the need for further study regarding appropriate monitoring parameters during the titration phase. Oral ketamine can be effective in treatment refractory chronic neuropathic pain of spinal origin.
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The possible role of spinal prostanoids in the tactile allodynia and thermal hyperalgesia associated with an experimental model of neuropathic pain was investigated. Neuropathic pain was induced by tight ligation of the L5 and L6 spinal nerves. Tactile allodynia was assessed 7 days after the surgery by measuring hindpaw withdrawal threshold to probing with von Frey filaments. ⋯ Finally, morphine, but not ketorolac, given i.th. produced dose-dependent anti nociception in either the tail-flick or the paw-flick tests. However, there was no synergy between morphine and ketorolac against thermal nociception in either of the tests. These findings suggest that spinal prostanoids produced via both COX1 and COX2 pathways may play a role in neuropathic pain states and suggest the clinical utility of opioid plus COX-inhibitor combination therapy.
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The co-administration of morphine at spinal (i.th.) and supraspinal (i.c.v.) sites to the same rat produces antinociceptive synergy, a phenomenon which may underlie the clinical analgesic utility of this drug. In animals with peripheral nerve injury, however, the antinociceptive potency and efficacy of i.th. morphine is significantly decreased. Here, the possible loss of spinal/supraspinal morphine antinociceptive synergy and relationship to elevation of spinal dynorphin content was studied. ⋯ These agents did not demonstrate antinociceptive or antiallodynic activity alone and did not alter morphine actions in sham-operated animals. The loss of spinal/supraspinal antinociceptive synergy and lack of antiallodynic activity of spinal morphine appear to be due to the elevation across multiple spinal segments of dynorphin following nerve injury. Pathological actions of elevated dynorphin may directly or indirectly modulate the NMDA receptor, result in a loss of supraspinal/spinal morphine synergy and may thus account for the decreased clinical analgesic efficacy of morphine in peripheral neuropathies.