Methadone for cancer pain: what have we learned from clinical studies?
The analgesic ladder guideline proposed by the World Health Organization has been shown to be effective in controlling cancer pain in about 80 percent of patients, but the remaining 20 percent still experience pain. Several strategies have been used to manage refractory cancer pain and opioid toxicity. Switching opioids, alternative routes of opioid administration, optimizing adjuvants, and invasive procedures are proposed treatments. Extensive medical literature corroborates each one of those treatments. Rotation from one opioid to another is a noninvasive strategy to overcome opioid side effects and refractory pain. Frequently, methadone is used during opioid rotation. However, there is a lack of consensus on how to proceed on rotation from morphine to methadone. In the current era of evidence-based medicine, the medical literature fails to answer some cancer pain-management issues. The purpose of this review is to clarify a process for transitioning from morphine to methadone.
Soares
Luiz Guilherme L
LG
Pain Clinic, National Cancer Institute, Rio de Janeiro, Brazil.
D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008691:Methadone / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D009020:Morphine / Q000627:therapeutic use; D009369:Neoplasms / Q000150:complications*; D010146:Pain / Q000188:drug therapy* / Q000209:etiology; D010147:Pain Measurement; D010166:Palliative Care / Q000379:methods*; D014944:World Health Organization
D000701:Analgesics, Opioid; D009020:Morphine; D008691:Methadone