title: Opioid-induced hyperalgesia after rapid titration with intravenous morphine: Switching and re-titration to intravenous methadone.
abstract: BACKGROUND
  Rapid titration with intravenous morphine (IV-MO) provides fast and efficient pain relief in cancer patients with severe-excruciating pain. However, some patients, after an initially favourable response, can develop an hyperexcitated state unrelieved or worsened by further dose increments.
  
  
  METHODS
  Eighty-one patients admitted on emergency basis titrated with IV-MO were assessed.
  
  
  RESULTS
  12 patients were unsuccessfully titrated with IV-MO. Switching to intravenous methadone (IV-ME) and titrating the doses proved to be successfully.
  
  
  CONCLUSIONS
  In escalating opioid doses rapidly a recognition of the development of hyperalgesia should be suspected. Increasing doses of opioids may stimulate rather than inhibiting the central nervous system, with complex mechanisms already recognized in experimental studies. Switching to IV-ME and titrating the doses could be taken into consideration to break this vicious circle before pain conditions worsen irreversibly.
authors.affiliation: Anesthesia and Intensive Care Unit, Pain Relief and Palliative Care Unit, La Maddalena Cancer Center, Via S. Lorenzo 312, 90146, Palermo, Italy. terapiadeldolore@lamaddalenanet.it; 03sebelle@gmail.com.
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Mercadante
authors.affiliation: Anesthesia and Intensive Care Unit & Pain Relief and Palliative Care Unit, La Maddalena Cancer Center, Palermo, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ferrera
authors.affiliation: Sacro Cuore Hospice, Rome, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Arcuri
authors.affiliation: Department of neuroscience, University of Palermo, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Casuccio
keywords: Cancer pain; opioid switching; opioid titration; opioid-induced hyperalgesia