Table 9: Opioid Equianalgesic Doses 83 (Continued) Medication
Approximate Equianalgesic Oral Dose
Approximate Equianalgesic Intravenous Dose
Conversion Factor to Oral Morphine
Tramadol
300 mg
0.1
Codeine
200 mg
0.15
Meperidine Oral morphine is about 10 times more potent than oral meperidine and about twice as potent as parenteral meperidine (mg for mg). ** Note : To convert to ER/LA opioids, see conversion factors listed in Common Opioids for Chronic Pain Management. Calculation of equianalgesic dosages Follow these three steps to calculate equianalgesic dosages when changing to a different opioid analgesic: Step 1: Calculate the total daily dose of the current opioid. Step 2: Determine the equianalgesic dose using the appropriate conversion factor or ratio. 300 mg of oral meperidine 75 mg of parenteral meperidine Step 3: Reduce the new opioid analgesic dose by 33% to 50% to account for cross-tolerance, dosing ratio variation, and patient variability. Determine a new regimen based on the available dosage form(s) of the new opioid. Clinical case example CD is a 32-year-old female with chronic pain. She is taking Exalgo 16 mg once daily and hydromorphone immediate-release 4 mg three times daily for breakthrough pain. The patient should be transitioned to MS Contin due to insurance issues. What dose of MS Contin should be started? Step 1: Calculate the total daily dose of the current opioid. Step 2: Determine the equianalgesic dose using the appropriate conversion factor or ratio
Oral hydromorphone to oral morphine conversion ratio: 4 28 mg hydromorphone/day × 4 = 112 mg morphine/day
28 mg hydromorphone =
equianalgesic dose of morphine
7.5 mg 30 mg Equianalgesic dose of morphine/day = 112 mg Step 3: Reduce dose by 33% to 50% to account for cross-tolerance; determine a new regimen based on available dosage forms of the new opioid.
Total daily dose of morphine = 74 to 56 mg/day New regimen: MS Contin 30 mg every 12 hours (Total morphine dose = 60 mg/day)
Prescribing of opioids in the management of acute and chronic noncancer pain in adults Pain is an unpleasant sensory and emotional
perception may be related to the site of the pain, such as the face or eye pain. Pain in children and pregnant women has unique considerations that a specialist should evaluate. In addition, pain accompanied by other physical and psychological conditions needs to be evaluated. Masking a comorbid condition by simply treating the pain could result in exacerbating
experience associated with actual or potential tissue damage or described in terms of such damage. 84 It is critical to understand that pain is not only a neuronal response but also involves cognitive processes that make it a subjective experience that does not require identifiable tissue damage to be significant. 85 Pain
Book Code: TN24CME
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