Seminars in Anesthesia, Perioperative Medicine and Pain
Equianalgesic dose guidelines for long-term opioid use: Theoretical and practical considerations
Section snippets
Clinical implications of short- and long-term use of opioids
Anesthesiologists are familiar with the use of opioids for short-term pain management during the perioperative period. Even with short-term use, there are wide variations in patient responses to opioid analgesics. A number of factors such as genetic differences in the response to pain, genetic variability amongst opioid receptors, and gender differences have been demonstrated to account for these differences.17, 18 Furthermore, tolerance, which is well known to occur with chronic opioid use,
Opioid rotation
Opioid rotation refers to the practice of changing from one opioid to another to improve pain control and/or reduce adverse effects and has recently been the subject of a number of extensive reviews.11, 16, 23, 24, 25, 26 Not all patients receiving opioids require opioid rotation. The incidence of opioid rotation in patients with chronic, nonmalignant pain has been reported as 32%,11 and it usually occurs for reasons related to inadequate pain relief. The occurrence of rotation is as high as
Strategies for overcoming tolerance
To counteract the effects of opioid tolerance, a number of strategies are employed. These include dose escalation, switching to alternative routes of administration, and opioid rotation. Drug rotation is an important strategy for managing poor opioid responsiveness, and the accuracy of conversion between agents and dosages is crucial to success.
Oral and subcutaneous
Established equianalgesic tables suggest that for the oral route, the EDR for morphine to hydromorphone is between 4:1 and 8:1 (30–60 mg of morphine = 7.5 mg of hydromorphone).1, 4
Recent studies have examined conversions between morphine and hydromorphone administered orally and subcutaneously. The EDR varies between 5:1 and 5.3:1 for conversions from morphine to hydromorphone for oral to oral and for subcutaneous to subcutaneous routes. When the drugs are switched in the opposite direction,
Recommendations for dose conversions
Converting patients from one opioid to another requires careful consideration, particularly if patients are opioid-tolerant or receiving high drug doses, and we recommend an approach that takes the adequacy of pain control into account. The equianalgesic table developed at our institution incorporates recent data concerning opioid conversions in patients on long-term therapy. Conversions should be relatively aggressive if the pain complaint is not well controlled; in these cases, patients are
Conclusions
Patients with chronic and cancer-related pain are frequently treated with high-dose opioids. It is not uncommon for patients to develop tolerance or severe adverse effects that require the substitution of another opioid. A number of pharmacodynamic and pharmacokinetic factors are responsible for wide variations in the older, established equianalgesic dose tables, and conversion from one long-term opioid to another must be undertaken with caution. The phenomenon of incomplete cross-tolerance may
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Cited by (9)
Use and Rotation of Opioids in Chronic Non-oncologic Pain
2012, Revista Brasileira de AnestesiologiaElderly Patients With Painful Bone Metastases Should be Offered Palliative Radiotherapy
2010, International Journal of Radiation Oncology Biology PhysicsCitation Excerpt :The Brief Pain Inventory assesses patients' worst, current, and average pain on an 11-point visual analog scale, with 0 representing the absence of pain and 10, worst possible pain, along with 7 functional interference items, and is also a validated tool (45). Analgesic intake was converted to a daily oral morphine equivalent dose (Appendix 1) (46–48). A patient's worst pain score is most related to their functional abilities and, therefore, was used to calculate the response to RT along with oral morphine equivalent dose (49).
Pharmacotherapy of Pain in Older Adults
2008, Clinics in Geriatric MedicineCitation Excerpt :Two such methods are shown in Tables 3 and 4, with examples in Appendix 1. More comprehensive reviews of equianalgesic dosage conversion can be found elsewhere [67,68]. It is important to note that equianalgesic conversions are estimates that may vary substantially, depending on the method of calculation used.
Variability in opioid equivalence calculations
2016, Pain Medicine (United States)Quality assessment of the methods used in published opioid conversion reviews
2012, Journal of Pain and Palliative Care Pharmacotherapy