L'hyperalgésie induite par les opioïdes

Opioids are used for the treatment of intense chronic pain. An increased sensitivity to pain i.e., an hyperalgesia, caused by a long-term opioid exposure (opioid induced hyperalgesia, OIH) is becoming more prevalent as the number of patients receiving opioids for chronic pain increases. OIH is a recognized complication of opioid treatment and is a pro-nociceptive process, related to, but different from opioid tolerance. A distinction between OIH, opioid tolerance and withdrawal syndrome is now able to be made. Multiple underlying pathways and various contributions, from systemic, cellular and molecular levels, have allowed proposing mechanisms at the origin of OIH: mu-opioid receptors (MOR), glutamatergic NMDA receptors, serotoninergic 5-HT3 receptors associated with descending pathways from RVM, spinal dynorphin, micoglial cells. New basic and clinical science concerning opioid activity and OIH will help to translate findings to the clinical phenomenon to prevent and treat OIH.