Before using this application, please review these important
Published equianalgesic ratios are considered
crude estimates at best and therefore it is imperative that careful consideration is given to individualizing the dose of the selected opioid. Dosage titration of the new opioid should be completed slowly and with frequent monitoring.
Factors that must be addressed during the conversion process include: Age of the patient or presence of coexisting conditions. Use additional caution with elderly patients (65 years and older), and in patients with liver, renal, or pulmonary disease.
Conversion ratios in many equianalgesic dosing tables do not apply to repeated doses of
The amount of residual drug in the patient's system must be accounted for. Example: fentanyl will continue to be released from the skin 12 to 36 hours after removal of the patch. Residual effects from discontinued long-acting formulations should also be assessed before converting a patient to a new
The use of high but ineffective doses of a previous opioid may result in overestimation of the converted opioid.
Ideally, methadone conversions (especially patients who were previously receiving high doses of an opioid) should only be attempted in cooperation with a pain specialist or a specialist in palliative medicine.
Meperidine should be used for acute dosing only and not used for chronic pain management (meperidine has a short half-life and a toxic metabolite: normeperidine). Its use should also be avoided in patients with renal insufficiency, CHF, hepatic insufficiency, and the elderly because of the potential for toxicity due to accumulation of the metabolite normeperidine. Seizures, confusion, tremors, or mood alterations may be seen. In patients with normal renal function, total daily doses should not exceed 600mg/24hrs.
for Health Care Policy and Research. Acute
Pain Management: Operative for Medical Procedures and Trauma. U.S.
Department of Health and Human Services. February
||American Pain Society. Principles
of Analgesic Use in the Treatment of Acute Pain and Cancer Pain, 4th
ed. Glenview, Ill. 1999.
||Anderson R, Saiers
JH, Abram S, Schlicht C.Accuracy in equianalgesic dosing. conversion dilemmas. J Pain Symptom Manage 2001 May;21(5):397-406
||Bruera E, Sweeney C.Methadone
use in cancer patients with pain: a review.J Palliat Med 2002
C.S. et al.
"Pain and Its Treatment in Outpatients with Metastatic
Cancer," N Engl J Med 330 (1994): 592-6.
||Coyle et al., "Character
of the Terminal Illness in the Advanced Cancer Patient: Pain and Other
Symptoms During the Last Four Weeks of Life," J Pain Sympt Mang 5
||Gagnon B, Bruera E.
Differences in the ratios of morphine to methadone in patients with
neuropathic pain versus non-neuropathic pain. J Pain Symptom Mgmt,
||Jacox, A., et al. Management
of Cancer Pain. Clinical Practice Guideline No. 9, AHCPR Publication No.
94-0592, Rockville, Md. Agency for Health Care Policy and Research, U.S.
Department of Health and Human Services, Public Health Service. 1994.
||Joranson, DE, Ryan KM, Gilson
AM, Dahl JL. Trends in medical use and abuse of opioid analgesics. JAMA,
||McCaffery, M., & Pasero,
C. Pain: Clinical Manual, 2nd ed. St. Louis: Mosby. 1999.
||Mercadante S, Casuccio A,
Fulfaro F, Groff L, Boffi R, Villari P, Gebbia V, Ripamonti C.Switching
from morphine to methadone to improve analgesia and tolerability in
cancer patients: a prospective study.J Clin Oncol 2001 Jun
||Mercadante S, Casuccio A, Calderone L. Rapid switching from morphine to methadone in cancer patients with poor response to morphine. J Clin Oncol 1999 Oct;17(10):3307-12.
Makin, MK,: The use of methadone in cancer pain poorly responsive to other
opioids. Pain Reviews. 1998, 5: 51-58.
||Moryl N, Santiago-Palma J,
Kornick C, Derby S, Fischberg D, Payne R, Manfredi PL.Pitfalls of opioid
rotation: substituting another opioid for methadone in patients with
cancer pain.Pain 2002 Apr;96(3):325-8
||Pereira J, Lawlor P, Vigano A, Dorgan M, Bruera E.Equianalgesic dose ratios for
opioids. a critical review and proposals for long-term dosing. J Pain Symptom Manage 2001 Aug;22(2):672-87
||Ripamonti C, Zecca E, Bruera E. An update on the clinical use of methadone for cancer pain. Pain 1997; 70: 109-15.
||Ripamonti C, Groff L, Brunelli C, Polastri D, Stavrakis A, De Conno F. Switching from morphine to oral methadone in treating cancer pain: what is the equianalgesic dose ratio? J Clin Oncol 1998 Oct;16(10):3216-21. Comment in: J Clin
Oncol. 1998 Oct;16(10):3213-5.
||Rowlingson JC. Classification
and Assessment of Chronic Pain. In Current Review of Pain 1994: Edited
by Raj PP. Philadelphia, PA: Current Medicine; 1994:37-46.
|1] Allerton C; Fox D (2013). Pain
Therapeutics: Current and Future Treatment Paradigms. Royal Society of
Chemistry. p. 79.
"Tramadol is highly bioavailable, up to 75%, and has about 20% of the
potency of morphine."
2] Berger AM, Shuster JL, Von Roenn JH, ed. Principles and Practice of
Palliative Care and Supportive Oncology, 3rd ed.. Philadelphia: Lippincott
Williams & Wilkins; 2007. p.51.
"Tramadol is thought to be approximately one tenth as potent as morphine
in patients with cancer(43)"
43. Grond S, Sablotzki A. Clinical pharmacology of tramadol. Clin
Dickman A. Drugs in Palliative Care. Oxford University Press (2012); p529.
"The literature suggests an equianalgesic ratio for PO tramadol:PO
morphine of 5:1. In practice, a 10:1 conversion is recommended because the
opioid analgesia derived from tramadol in the clinical situation is
unknown due to the dependence upon CYP2D6 activity."
Fukuda K. Opioid Analgesics. (chapter) in: Miller's Anesthesia. ed. Miller
RD et al. Elsevier Health Sciences, 8th edition, 2014.
Tramadol is one fifth to one tenth as potent as morphine.
Peck, T. E.; Hill, S. A.; Williams, M. (2008). Pharmacology for
Anaesthesia and Intensive care (3rd edition). Cambridge: Cambridge
University Press. p. 139.
Tramadol: "Its analgesic potency is one-fifth to one-tenth that of