Before using the data below, 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
Review the concept of incomplete
D. McAuley: "Incomplete cross-tolerance relates to
tolerance to a currently administered opiate that does not
extend completely to other opioids. This will tend to lower the
required dose of the second opioid. This incomplete
cross-tolerance exists between all of the opioids and the
estimated difference between any two opiates could vary widely.
This points out the inherent dangers of using an equianalgesic
table and the importance of viewing the tabulated data as
approximations. Many experts recommend - depending on age and
prior side effects - reducing the dose of the new opiate by 33
to 50 percent to account for this incomplete cross-tolerance.
(Example: a patient is receiving 200mg of oral morphine daily
(chronic dosing), however, because of side effects a switch is
made to oral hydromorphone 25 - 35mg daily - (this represents a
33 to 50 percent reduction in dose compared to the calculated
50mg conversion dose produced via the equianalgesic calculator).
This new regimen can then be re-titrated to patient response. In
all cases, repeated comprehensive assessments of pain are
necessary in order to successfully control the pain while
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.
RECOMMENDED INITIAL DURAGESIC®
DOSE BASED UPON DAILY ORAL MORPHINE DOSE4
NOTE: In clinical trials,
these ranges of daily oral morphine doses were
used as a basis for conversion to DURAGESIC®.
should not be used to convert from DURAGESIC®
to other therapies because this conversion to
conservative. Use of this table for conversion
to other analgesic therapies can overestimate
the dose of the new agent.
Discontinuation of DURAGESIC®:
To convert patients to another opioid, remove
DURAGESIC® and titrate the dose of the new
analgesic based upon the patient's report of pain
until adequate analgesia has been attained. Upon
system removal, 17 hours or more are required for
a 50% decrease in serum fentanyl concentrations.
Opioid withdrawal symptoms (such as nausea,
vomiting, diarrhea, anxiety, and shivering) are
possible in some patients after conversion or dose
adjustment. For patients requiring discontinuation
of opioids, a gradual downward titration is
recommended since it is not known at what dose
level the opioid may be discontinued without
producing the signs and symptoms of abrupt
1] American Pain Society (APS). Principles of Analgesic Use in the Treatment of Acute Pain and Cancer Pain, 6th edition. 2008. Glenview, IL 60025.
2] Ayonrinde OT, Bridge DT. The rediscovery of methadone for cancer pain management. Med J Aust 2000; 173(10): 536-540.
3] Breitbart W, Chandler S, Eagel B, et al. An alternative
algorithm for dosing transdermal fentanyl for
cancer-related pain. Oncology. 2000;14:695-705.
5] Donner B, et al. Direct conversion from oral morphine
to transdermal fentanyl. Pain. 1996; 64:527-534.
6] Fisch MJ, Cleeland CS: Managing cancer pain. In: Skeel RT, ed.: Handbook of Cancer Chemotherapy. 6th ed. Philadelphia, Pa: Lippincott Williams & Wilkins, 2003, pp 663.
7] Methadone PI (package insert). Dolophine hydrochloride, 5 mg, 10mg tablets. Oct .2006.
8] 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;16(10):3216-3221.
15-30 mg (20 mg)
130-200 mg *
*Propoxyphene HCL: 130mg; Napsylate: 200mg. Not recommended for chronic pain.
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