Morphine Equivalency of Hydromorphone
0.5 mg of hydromorphone is equivalent to 2.5 mg of morphine based on the most recent CDC guideline conversion factor of 5:1. 1
Conversion Factors for Hydromorphone
The conversion of hydromorphone to morphine milligram equivalents (MME) is essential for:
- Calculating total opioid burden
- Comparing analgesic doses across different opioids
- Ensuring safe prescribing practices
According to the most recent guidelines:
- The 2022 CDC Clinical Practice Guideline for Prescribing Opioids for Pain indicates a conversion factor of 5.0 for hydromorphone 1
- Earlier guidelines from 2016 used a conversion factor of 4.0 1
Calculation
Using the current CDC conversion factor:
- 0.5 mg hydromorphone × 5.0 = 2.5 mg morphine equivalent
Route of Administration Considerations
The conversion factor applies to the same route of administration. If converting between routes:
- For IV/parenteral hydromorphone to oral morphine: The conversion is more complex
- Parenteral opioids are typically one-third the oral dose 1
- Therefore, 0.5 mg IV hydromorphone would be equivalent to approximately 7.5 mg oral morphine
Clinical Implications
- Hydromorphone is significantly more potent than morphine
- Small dose changes of hydromorphone can result in substantial changes in analgesic effect
- When rotating between opioids, it's recommended to reduce the calculated dose by 25-50% due to incomplete cross-tolerance 2
Special Considerations
- Higher doses of hydromorphone (≥30 mg/day) may require a lower conversion ratio to other opioids 3
- Patients with renal impairment require careful monitoring as hydromorphone metabolites may accumulate 1
- Clinical studies have confirmed that approximately 1 mg of IV hydromorphone is equianalgesic to 10 mg of IV morphine 4
Understanding these equivalencies is crucial for safe opioid prescribing and preventing adverse effects including respiratory depression, while maintaining adequate pain control.