From the Guidelines
The Morphine Equivalent Dose (MEDD) of 18mg hydromorphone Intravenous (IV) is 90mg.
Calculation of MEDD
To calculate the MEDD, we use the conversion factor for hydromorphone, which is 5.0, as stated in the CDC clinical practice guideline for prescribing opioids for pain - United States, 2022 1.
- The dose of hydromorphone is 18mg.
- The conversion factor for hydromorphone is 5.0.
- MEDD = dose of hydromorphone * conversion factor = 18mg * 5.0 = 90mg.
Important Considerations
When converting between opioids, it is essential to consider individual variability in genetics and pharmacokinetics, as well as incomplete cross-tolerance 1.
- The calculated MEDD should not be used to determine the dose when converting one opioid to another; instead, the new opioid should be dosed at a substantially lower dose than the calculated MEDD to avoid overdose.
- Particular caution should be exercised when converting to methadone due to its long and variable half-life, and peak respiratory depressant effect occurs later and lasts longer than peak analgesic effect 1.
Clinical Application
In clinical practice, the MEDD can be used to guide opioid conversions, but it is crucial to consider the specific clinical context and individual patient factors, such as renal function, liver function, and history of opioid use 1.
- For example, when converting from IV morphine to IV hydromorphone, a reduction in dose by 25%-50% may be necessary to account for individual variability and incomplete cross-tolerance 1.
The FDA Drug Labels for hydromorphone (IV), morphine (PO) do not address this question.
From the Research
Morphine Equivalent Dose (MEDD) of 18mg Hydromorphone IV
- The MEDD of 18mg hydromorphone IV can be calculated using the opioid rotation ratio (ORR) from IV hydromorphone to oral morphine equivalent daily dose (MEDD) found in the study by 2.
- According to the study, 1mg of IV hydromorphone is equivalent to 11.46mg of MEDD.
- To calculate the MEDD of 18mg hydromorphone IV, multiply the dose of hydromorphone by the ORR: 18mg x 11.46mg/mg = 206.28mg MEDD.
- However, it is essential to note that the study also found that hydromorphone at doses ≥30mg/day may require a lower ORR to other opioids, but since 18mg is less than 30mg, this may not be directly applicable.
Comparison with Other Studies
- Other studies, such as 3 and 4, discuss the variation in conversion ratios and opioid rotation ratios among pain specialists and palliative care professionals, but do not provide specific data for calculating the MEDD of 18mg hydromorphone IV.
- Study 5 focuses on the conversion from methadone to other opioids and does not provide relevant information for calculating the MEDD of hydromorphone.
- Study 6 discusses the conversion from prior opioid therapy to an extended-release hydromorphone formulation, but uses a different conversion ratio (5:1, morphine equivalent to hydromorphone) that is not directly applicable to calculating the MEDD of 18mg hydromorphone IV.