Comparison of a novel methadone rotation method with other commonly used methods.

Objectives: To compare a novel method of methadone rotation used in a specialist palliative care inpatient unit (SPCU) in Cork, Ireland, with rapid titration methods using Perth and Brisbane Protocols as well as the Edmonton method of methadone rotation.

Methods: A retrospective chart review was performed in March-June 2022. All patients who completed rotation to methadone during 2018-2019 in the SPCU were included. 2018-2019 was selected to study a population not affected by the coronavirus pandemic. Oral morphine equivalent (OME) was calculated using the opioid conversion chart. From the OME, the expected daily methadone dose was calculated using the Perth, Brisbane and Edmonton methods. These figures were then compared directly with the actual methadone doses achieved using our dosing schedule.

Results: A comparison of the expected doses using the Perth and Brisbane rapid titration protocols and stable daily dose achieved revealed that the stable methadone dose was significantly lower than both rapid titration protocols (p=<0.0001) and (p=0.0035, respectively). However, a comparison of the expected dose using the Edmonton method and the dose achieved did not determine any significant difference (p=0.7602).

Conclusions: This is the first evaluation of a novel Irish method of methadone rotation and demonstrates a lower overall daily methadone dose compared with established protocols.