Purpose: The aim of this study was to evaluate the analgesic and adverse effects and the doses of methadone in comparison to morphine.
Patients and methods: A prospective randomized study was performed in a sample of 40 patients with advanced cancer who required strong opioids for their pain management. Patients were treated with sustained-release morphine or methadone in doses titrated against the effect administered two or three times daily according to clinical need. Opioid doses, adjuvant medications, symptoms associated with opioid therapy, pain intensity, and pain mechanisms were recorded. The opioid escalation indices in percentage (OEI%) and milligrams (OEImg) were calculated. The effective analgesic score (EAS) that monitors the analgesic consumption-pain ratio was also calculated at fixed weekly intervals.
Results: differences in pain intensity were found. Patients treated with methadone reported values of OEI significantly less than those observed in patients treated with morphine. Seven patients in the methadone group maintained the same initial dosage until death, whereas only one patient in the morphine group did not require opioid dose escalation. A more stable analgesia in time in patients treated with methadone was shown by the low number of gaps in EASs reported. Symptom frequencies and intensities were similar in the two groups.
Conclusion: Methadone is a drug of indisputable value in the treatment of cancer pain, and an unbalanced focus on the risks of inappropriate use rather than the benefits should not compromise the use of a relevant alternative to morphine in the management of cancer pain.