title: Multi-mechanistic analgesia for opioid-induced hyperalgesia.
abstract: OBJECTIVE
  The phenomenon of opioid-induced hyperalgesia (OIH), an increased sensitivity to pain attributed to the very opioid drugs administered to manage the pain, is well established in animal models, and there is concern that it also occurs in patients. Our objective is to briefly summarize the basic science and clinical evidence about OIH as background to consider the possible benefit of using a multi-mechanistic analgesic approach.
  
  
  CONCLUSIONS
  It is unclear how OIH occurs, or even why; presumably, it is part of an adaptive response. But development of OIH poses a serious treatment dilemma. OIH differs from tolerance, which also presents as reduced analgesic effect, in that tolerance is addressed by judicious and monitored increase in opioid dose, but OIH would be treated by a decrease in opioid dose. Therefore, it is important to avoid induction of OIH. Currently, it is not clear which patients are at greater risk of developing OIH, or which drugs are at greater risk of producing it.
  
  
  CONCLUSIONS
  We suggest that multi-mechanistic analgesia, accomplished within either a single drug or a combination of drugs, is a logical approach that might result in a reduced development of OIH.
authors.affiliation: Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, PA 19140, USA. robert.raffa@temple.edu
authors.forename: R B
authors.initials: RB
authors.lastname: Raffa
authors.forename: J V
authors.initials: JV
authors.lastname: Pergolizzi
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects*; D000818:Animals; D006801:Humans; D006930:Hyperalgesia / Q000139:chemically induced* / Q000517:prevention & control; D010146:Pain / Q000188:drug therapy*; D012307:Risk Factors
chemical_list: D000701:Analgesics, Opioid