Abstract:

Opiate analgesics remain the primary source of pain relief in conditions ranging from moderate to severe postoperative and chronic pain. Chronic opioid consumption induces paradoxical hyperalgesia (opioid-induced hyperalgesia; OIH). OIH is characterized by hypersensitivity to innocuous or noxious stimuli during sustained opiate administration, and is recognized in clinical and pre-clinical settings. The mechanisms proposed to be essential for the development of OIH include neuroadaptive alterations in the pain modulatory circuitry and activation of supraspinal pain facilitatory pathways but the exact underlying mechanisms remain unknown.