Extreme doses of intravenous methadone for severe pain in two children with cancer.

We describe the effect and side effects in two children with cancer treated with intravenous methadone in extreme doses (>10 mg/kg/day) due to vincristine-induced neuropathy where surgical procedures provoked severe neuropathic pain. The maximum daily dose was 33 and 25 mg/kg/day. Methadone remained effective at adjusted doses. Few side effects were reported. No significant changes in paraclinical data were observed. Prolonged QTc-interval occurred only during concomitant treatment with fluconazole. In conclusion, methadone should be seen as a part of the armamentarium against cancer-related pain. Methadone can be used in extreme doses with appropriate monitoring by clinicians experienced in its use.