Is there a validated and accepted schematic to determine morphine daily equivalent dose?
No. The concept of morphine equivalents was employed because the daily dose of various opioids may not reflect their clinical potencies. However, the daily dose of one opioid does not necessarily exhibit the same effects of the daily dose of another opioid. This distinction then creates a problem clinically when opioid use or transition to another opioid is being evaluated. The concept of morphine daily equivalents was created in order to convert between opioids; however, due to the variations in equivalence calculators and numerous sources having different potency equivalent estimators, these calculators are flawed. There is no consideration given to interpatient variability and attributes that differ among opioids. Other factors to be considered are pharmacogenetics, organ dysfunction, overall pain control, drug tolerance, drug-drug interactions, drug-food interactions, patient age, and body surface area. Single-dose studies, expert opinion, and observations are largely the source from which equianalgesic tables are derived.
