Background: Use of methadone for the management of pain is increasing. Despite this there is variability in methods of prescription including: adjunctive vs. full opioid rotation, use for neuropathic vs. nociceptive pain, and opioid to methadone ratios.

Aim: To describe (1) patterns of methadone prescription for pain management by palliative care in a quaternary setting, (2) efficacy and tolerability of methadone and (3) optimal pain-type indications.

Methods: Details of methadone prescription by a palliative care consultation-liaison service in an acute hospital were analysed between 2019-2022. Prescriptions in outpatient settings, performed by non-palliative care clinicians, and for indications other than pain were excluded. Initial prescribing doses, adjuvant use, opioid rotation, or initial primary opioid, methadone conversion ratio, efficacy, and adverse events were recorded.

Results: Fifty seven patients were included; Rotation from another opioid occurred for 20 (35%) patients, adjunctive use of methadone for 35 (61%), and methadone as an initial opioid agent for two patients (4%). Improvement in pain occurred for 38 (72%) patients. For patients with nociceptive pain, 58% responded (14/24), compared to 80% for neuropathic pain (4/5), and 74% for mixed neuropathic/nociceptive (20/27). Titration of methadone to final dose required 14 days for adjuvants and 10 days for full rotation. Adverse events occurred in 16 (27%). Cessation was required in 5 (12%) of adjuvants and 1 (5%) in the rotational group. 

Conclusions:  Our findings support literature that methadone is safe and effective when used for pain in palliative care. Interestingly, our study challenges the notion that adjunctive methadone is better tolerated and faster to titrate than full methadone rotation. Prospective studies should further evaluate time taken to final methadone dose and tolerability for full rotation versus adjunctive methadone.