Before using this application, please review these important
points:
 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
opioids.
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
opioid.
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.
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Tramadol
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1] Allerton C; Fox D (2013). Pain
Therapeutics: Current and Future Treatment Paradigms. Royal Society of
Chemistry. p. 79.
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"Tramadol is highly bioavailable, up to 75%, and has about 20% of the
potency of morphine."
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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.
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Dickman A. Drugs in Palliative Care. Oxford University Press (2012); p529.
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"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."
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Fukuda K. Opioid Analgesics. (chapter) in: Miller's Anesthesia. ed. Miller
RD et al. Elsevier Health Sciences, 8th edition, 2014.
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Tramadol is one fifth to one tenth as potent as morphine.
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Peck, T. E.; Hill, S. A.; Williams, M. (2008). Pharmacology for
Anaesthesia and Intensive care (3rd edition). Cambridge: Cambridge
University Press. p. 139.
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Tramadol: "Its analgesic potency is one-fifth to one-tenth that of
morphine."
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