ONLINE RESOURCES ABOUT PRESCRIBING METHADONE FOR CANCER PAIN
CONVERSION PROTOCOLS TO SWITCH TO METHADONE
The conversion protocols below reflect current practice in various settings, and the developers' clinical observations of patients' experience. Some protocols rely on patient-controlled analgesia with fixed doses and flexible intervals, some require fixed intervals and fixed doses, while others stagger the conversion over a few days. Whatever method is chosen, conversion can be safe and effective as long as regular assessments are provided over time.
Bruera E, Pereira J, Watanabe S, et al. Opioid rotation in patients with cancer pain.Â A retrospective comparison of dose ratios between methadone, hydromorphone, and morphine. Cancer 1996; 78 (4): 852-857.
In this approach, developed in Edmonton, switching from morphine to methadone occurs slowly over 3 days, giving clinicians time to make adjustments; it is useful for patients receiving >100mg of morphine equivalent dose per day. [protocol not available online]
Tse DM, Sham MM, Ng DK, Ma HM. An ad libitum schedule for conversion of morphine to methadone in advanced cancer patients: an open uncontrolled prospective study in a Chinese population. Palliat Med 2003; 17(2):206-211.
This approach calls for the previous dose to be discontinued and a single fixed-dose of methadone to be given at the start at intervals selected by the patient. [see abstract]
Nauck F, Ostgathe C, Dickerson ED. A German model for methadone conversion. Am J Hosp Palliat Care 2001; 18:200-202.
In this protocol, the use of morphine is stopped immediately. This method is suggested when patients are switched from high equivalent daily doses of morphine (>600 mg orally per day). [protocol not available online]
Ripamonti C, Groff L, Brunelli C, et al. Switching from morphine to oral methadone in treating cancer pain: what is the equianalgesic dose ratio? J Clin Oncol 1998; 16: 3216-3221.
This protocol describes a slow switch from morphine to methadone over a few days. Download article online from: http://www.jco.org/cgi/content/abstract/16/10/3216
Guidelines for methadone administration in the United Kingdom (1998).
Methadone has been used in UK hospices since the recommendation of the Pain Relief Foundation in 1993. This model allows the rapid replacement of morphine with methadone. See: Morley JS, Makin MK. The use of methadone in cancer pain poorly responsive to other opioids. Pain Rev 1998;5:51-58. Protocol available online at: http://www.tapm.org/vault/Converting_to_Methadone.pdf
Guidelines for the use of methadone for cancer pain (2004).
Guidelines for the use of methadone were published in the March 2004 Newsletter of the http://www.palliativedrugs.com website.
This website was founded to promote and disseminate information about the use of drugs in palliative care.
Information (summarized in two pages for ease of use in the clinical setting) is derived from Twycross R, Wilcock A, Charlesworth S, Dickman A. Palliative Care Formulary-Second Edition, Oxford: Radcliffe Medical Press, 2002 and from Twycross R, Wilcock A. Symptom Management in Advanced Cancer-3rd Edition,Oxford: Radcliffe Medical Press, 2001.
Protocol available online at: http://www.palliativedrugs.com
The http://www.palliativedrugs.com website also features a bulletin board debate on methadone conversion.
Facts and Concepts #86. Methadone: Starting dose information. Von Gunten, CF, March 2003. End-of-Life Physician Education Resource Center www.eperc.mcw.edu
This fast fact reviews principles of methadone dosing in patients starting methadone for the first time.
Fast Facts and Concepts #75. Methadone for the treatment of pain. Gazelle G, Fine PG. September 2002. End-of-Life Physician Education Resource Center www.eperc.mcw.edu
This fast fact reviews the pertinent clinical information to prescribe and monitor methadone for pain.
WORLD HEALTH ORGANIZATION
WHO. Essential Medicines List (2005).
The WHO Model List of Essential Medicines has been updated every two years since 1977. The current version, the 14th list, dates from March 2005. It includes methadone.