title: [Opioids for treating non malignant chronic pain: the role of methadone.].
abstract: OBJECTIVE
  The use of opioids for cancer pain has already well established by several well-controlled clinical trials. However, there is a major controversy about long-term use of opioids in non-malignant chronic pain, which has been significantly intensified in the last few years. This study aimed at evaluating available data on the use of opioids for treating non-malignant chronic pain and the role of methadone as a therapeutic alternative.
  
  
  BACKGROUND
  There are few available studies, but they show that some subpopulations of chronic pain patients may achieve sustained analgesia with minor tolerance and low addiction potential, mainly those refractory to conventional therapy. Morphine is the standard opioid, but other alternatives may be used such as oxycodone, hydromorphone or fentanyl. Methadone is a synthetic opioid, initially used to prevent withdrawal syndrome in addicted patients, which may be an important alternative for treating non-malignant chronic pain, especially neuropathic pain.
  
  
  CONCLUSIONS
  Although the growing knowledge on the use of opioids for treating non-malignant chronic pain, new better controlled studies are still needed to allow a more scientific discussion about this subject. Oral methadone is cost-effective and an effective alternative for a better pain control in certain patients.
authors.affiliation: American Pain Board of Medicine, Department of Neurobiology, University of Texas, Houston, Texas, USA.
authors.forename: Sady
authors.initials: S
authors.lastname: Ribeiro
authors.forename: André Prato
authors.initials: AP
authors.lastname: Schmidt
authors.forename: Sérgio Renato Guimarães
authors.initials: SR
authors.lastname: Schmidt