Background: Cancer pain is often not well controlled and there is a need for improved treatment strategies. Methadone exhibits unique properties among opioids and recent reports show promising results from adding a low dose of methadone to regular opioid therapy.
Objective: To examine the effects of oral low-dose methadone added to regular scheduled opioids in terminally ill patients with complex cancer-related pain.
Design: This was a retrospective chart review.
Setting/subjects: All patients with advanced cancer treated in a specialized palliative care unit who had received oral methadone in addition to another regular opioid were identified.
Measurements: Intensity of pain, opioid doses, and occurrence of sedation, delirium, and respiratory depression were obtained from the patients' medical records for a period of one week after initiation of methadone.
Results: Eighty patients were included. The median daily methadone dose was 10 mg during the treatment period. Eighty percent of the patients had improved pain control (p < 0.001). There was an increased risk for sedation and delirium, most pronounced in patients living 14 days or less after the start of methadone. No patient experienced respiratory depression.
Conclusion: Addition of low-dose oral methadone to regular high-dose opioid treatment in cancer patients with complex pain close to death improves pain control, but also increases the risk for sedation and delirium.
Keywords: cancer pain; delirium; methadone; opioid; palliative care; sedation.