Clinical Outcomes of Methadone for Refractory Cancer Pain, Including Add-On Switching to Prior Opioids

Methadone has emerged as an effective treatment for refractory cancer pain. In Japan, guidelines recommend methadone for patients with cancer pain refractory to strong opioids, using methods like the stop-and-go(SAG)approaches. However, the optimal methadone-switching strategy remains unclear.

A retrospective analysis was conducted on 34 patients treated with methadone for refractory cancer pain. Methadone switching methods, efficacy, and adverse events were evaluated.

Of the 32 evaluable cases, 18.7% underwent the SAG method, while 81.2% received the add-on method. NRS scores improved in 93.7% of patients, with 66.6% in the SAG group and 100% in the add-on group reporting reductions. Optimal dosing was achieved in 62.5% of patients, with fewer adverse events in the add-on group. Methadone introduction via the add-on method allowed continued use of prior opioids, facilitating pain management while minimizing risks.

Methadone proved effective for refractory cancer pain, particularly using the add-on method, which tend to be equally safe and effective as well as the SAG approach. The add-on method's flexibility in maintaining prior opioid regimens may support its use in clinical practice.