Auret, K., Roger Goucke, C., Ilett, K.F., Page-Sharp, M., Boyd, F., & Oh, T.E. (2006). Pharmacokinetics and pharmacodynamics of methadone enantiomers in hospice patients with cancer pain. Therapeutic Drug Monitoring, 28, 359–366.

To elucidate the pharmacology of methadone in palliative care patients with advanced cancer who have switched from morphine to methadone

• The sample was composed of 13 patients. Three patients did not complete the entire protocol.
• The sample consisted of patients with cancer pain that was poorly controlled with morphine or for whom morphine caused unacceptable side effects.

• Multisite
• Inpatient and outpatient palliative care services
• Perth, Western Australia

• Relationship between original serum morphine concentrations and final R- and S-methadone
• Degree of control of cancer pain and side effects

• Six patients achieved optimal pain control, but authors observed no obvious relationship between pain control and the plasma concentrations of either enantiomer.
• Of all patients, 46% of those who changed from morphine to methadone experienced an improvement in pain control.

The study had a small sample size.

Further studies, to determine if methadone is better than morphine for the treatment of neuropathic pain, are warranted.