Opioid Conversion Calculator

Understanding Morphine Milligram Equivalents (MME) and Opioid Rotation

The Opioid Conversion and MME Calculator calculates total daily Morphine Milligram Equivalents (MME) for prescribed opioids and estimates safer starting dosages when transitioning (rotating) between medications. Calculating MME provides a standardized metric to assess overdose risk, evaluate therapy intensity, and adhere to clinical guidelines.

Why Calculate Daily MME?

Different opioid agonists possess distinct receptor binding affinities and potencies. A milligram of hydromorphone or oxycodone is significantly more potent than a milligram of oral morphine or codeine. Converting individual drug amounts into MME provides a uniform gauge of opioid exposure:

• Below 50 MME/day: Generally considered baseline lower risk for standard chronic non-cancer pain management.
• 50 to 89 MME/day: Moderate risk threshold. The CDC recommends carefully justifying dose escalations and re-evaluating pain relief versus sedation and respiratory depression risks.
• 90+ MME/day: High risk category. Clinical guidelines recommend avoiding increases to 90 MME/day or higher without comprehensive specialist consultation and co-prescribing naloxone.

CDC Conversion Factor Reference Table

Managing Incomplete Cross-Tolerance

When a patient switches from one opioid medication to another, tolerance to the existing drug does not completely carry over to the new opioid. Administering 100% of the calculated equianalgesic dose can lead to unintended oversedation or respiratory depression. Standard clinical protocols advise initiating the new drug at 25% to 50% below the theoretical equianalgesic dose.