Methadone initiation and rotation in the outpatient setting for patients with cancer pain

BACKGROUND: Methadone is an effective and inexpensive opioid for cancer pain treatment. It has been reported as difficult to use in the outpatient setting because of its variable relative potency and long half-life. The purpose of this study was to determine the outcome of methadone initiation or rotation for cancer pain treatment in outpatient settings. METHODS: Chart review was done of 189 consecutive patients who underwent methadone initiation or rotation at the authors' palliative care outpatient center. Data were collected regarding demographic and clinical characteristics, symptoms, and opioid side effects at baseline and for 2 follow-up visits (F1, F2). Failure was defined as methadone discontinuation by the palliative care physician or patient's hospitalization for uncontrolled pain or methadonerelated side effects at F1. RESULTS: One hundred (53%) initiations and 89 (47%) rotations were conducted. Success rates for methadone initiation and rotation were 82 of 89 (92%) and 85 of 100 (84%), respectively. Mean (standard deviation) age was 60 (11) years. One hundred (53%) patients were women, 138 (73%) were white, and 182 (96%) had solid cancers. The main reason for rotation was pain (65 of 89 patients, 47%). Median (interquartile range, IQR) pain scores (Edmonton Symptom Assessment Scale/0-10) were 6 (5-8), 4 (3-6), and 3 (2-5) at baseline, F1, and F2, respectively (P < .0001). Median (IQR) daily methadone dose for initiation and rotation was 10 (5-15) mg and 15 (10-30) mg at F1 (P < .0001) and 10 (8-15) mg and 18 (10-30) mg at F2 (P < .0001), respectively. Constipation and nausea improved (P < .005) after initiation/rotation to methadone. Frequency of sedation, hallucinations, myoclonus, and delirium did not increase after initiation/rotation to methadone. CONCLUSIONS: Outpatient methadone initiation and rotation for cancer pain treatment were safe, with high success rates and low side effect profiles.