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Opioid analgesic converter

 Check out the new advanced version for methadone related conversions....

Converting From:

Step 1
Step 2: (Enter total daily dose in mg)

Incomplete cross-tolerance correction

Step 3:  Reduction for incomplete cross tolerance:
(Usual range: 25 - 75% reduction)

Converting To:

Step 4: 

Before using this application, please review these important points:

bullet 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. 

bulletFactors 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. 

bullet Conversion ratios in many equianalgesic dosing tables do not apply to repeated doses of opioids.

bulletThe 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 opioid.

bullet The use of high but ineffective doses of a previous opioid may result in overestimation of the converted opioid. 

bullet 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. 

bullet 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. 


Conversion Data

The narcotic analgesic converter is based on the following table:
Note: levorphanol, oxymorphone, and propoxyphene have been eliminated from the calculator.
Drug  Duration     Half-life    Route       Equianalgesic
Codeine 4-6 h 3 h IM/IV/SC 120 mg
      PO 200 mg
Fentanyl 1-2 h 1.5-6 h IM/IV 0.1 - 0.2 mg
Hydrocodone 4-8 h 3.3-4.5 h PO 20-30 mg
Hydromorphone 4-5 h 2-3 h IM/IV/SC 1.3-1.5 mg
      PO 7.5 mg
Levorphanol 6-8 h 12-16 h IM/IV/SC 2 mg
      PO 4 mg
Meperidineæ 2-4 h 3-4 h IM/IV/SC 75 mg
      PO 300 mg
Methadone 4-6 h 15-30 h IM/IV/SC 1-10 mg§   Medline
Short term: 5-10mg
Chronic use: 1-4 mg  
     (2 mg)
      PO 2 - 20 mg§  Medline
Short term use: 20 mg
Chronic dosing: 2-4 mg 
Morphine 3-6 h 1.5-3 h IM/IV/SC 10 mg
      PO 30-60 mg#
Oxycodone 4-6 h NA PO 15-30 mg (20 mg)
Oxymorphone 3-6 h NA IM/IV/SC 1 mg
Important Update: Opana™ and Opana ER™ (oxymorphone immediate release and oxymorphone extended release tablets) have been approved by the FDA.  
PO 10 mg
Propoxyphene 4-6 h 6-12 h PO 130-200 mg *
Tramadol 9 h 6 - 8 h PO 150-300
* Propoxyphene HCL: 130mg;  Napsylate: 200mg. Not recommended for chronic pain management and therefore not available in program above.
# Acute dosing (opiate naive): 60mg.   Chronic dosing: 30 mg.
§: Many equianalgesic tables underestimate methadone potency - more studies are needed. Parenteral: Program utilizes 10mg for short-term dosing and 2 mg for chronic dosing.  Oral: Program utilizes 20mg for short-term dosing and 3 mg for chronic dosing.
æ  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. 


Completed Medline Search
1. Agency for Health Care Policy and Research. Acute Pain Management: Operative for Medical Procedures and Trauma. U.S. Department of Health and Human Services. February 1992:1-27..
2. American Pain Society. Principles of Analgesic Use in the Treatment of Acute Pain and Cancer Pain, 4th ed. Glenview, Ill. 1999.
3. Anderson R, Saiers JH, Abram S, Schlicht C.Accuracy in equianalgesic dosing. conversion dilemmas. J Pain Symptom Manage 2001 May;21(5):397-406 
4. Bruera E, Sweeney C.Methadone use in cancer patients with pain: a review.J Palliat Med 2002 Feb;5(1):127-38
5. Cleeland, C.S. et al. "Pain and Its Treatment in Outpatients with Metastatic Cancer," N Engl J Med 330 (1994): 592-6.
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 (1990): 84.
7. 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, 1999;18:120-125.
8. 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.
9. Joranson, DE, Ryan KM, Gilson AM, Dahl JL. Trends in medical use and abuse of opioid analgesics. JAMA, 2000;283:1710-1714.
10. McCaffery, M., & Pasero, C. Pain: Clinical Manual, 2nd ed. St. Louis: Mosby. 1999.
11. 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 1;19(11):2898-904
12. 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.
13. Morley, JS, Makin, MK,: The use of methadone in cancer pain poorly responsive to other opioids. Pain Reviews. 1998, 5: 51-58.
14. 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
15. 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 
16. Ripamonti C, Zecca E, Bruera E. An update on the clinical use of methadone for cancer pain. Pain 1997; 70: 109-15.
17. 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.
18. 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 Pharmacokinet 2004;43(13):879-923.

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 morphine."

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