From the Guidelines
The morphine milligram equivalent (MME) for opioid conversion should be calculated using the most recent conversion factors, which include: oral hydrocodone (1 MME = 1 mg), oral oxycodone (1 MME = 1.5 mg), oral hydromorphone (1 MME = 5 mg), oral methadone (varies based on daily dose, with a conversion factor of 4.7), and fentanyl patches (1 mcg/hr = 2.4 MME daily) 1. When converting between opioids, it's essential to calculate the total daily MME, then convert to the new opioid using its specific conversion factor, typically reducing the calculated dose by 25-50% to account for incomplete cross-tolerance. Some key points to consider when using MME for opioid conversion include:
- The conversion factors are estimates and may not account for individual variability in genetics and pharmacokinetics 1.
- Methadone dose conversions require particular caution due to its long and variable half-life, and peak respiratory depressant effect occurs later and lasts longer than peak analgesic effect 1.
- Fentanyl patches are dosed in mcg/hr instead of mg/day, and their absorption is affected by heat and other factors, requiring careful consideration when converting to or from other opioids 1. Regular reassessment of pain control and side effects is necessary when adjusting opioid regimens. The CDC recommends caution when prescribing ≥50 MME daily and avoiding or carefully justifying dosages ≥90 MME daily, although this information is not found in the most recent study 1, it is found in other studies such as 1. The most recent and highest quality study provides the conversion factors, which should be used to guide clinical decision-making 1.
From the FDA Drug Label
Conversion from Parenteral Morphine to Morphine Sulfate Tablets: For conversion from parenteral morphine to morphine sulfate tablets, anywhere from 3 to 6 mg of oral morphine sulfate may be required to provide pain relief equivalent to 1 mg of parenteral morphine
The morphine milligram equivalent (MME) for opioid conversion is not directly provided in the given drug labels. However, it can be inferred that 3 to 6 mg of oral morphine sulfate is equivalent to 1 mg of parenteral morphine. To determine the MME, a conversion factor is typically used, but this information is not explicitly provided in the labels 2 2.
From the Research
Morphine Milligram Equivalent (MME) for Opioid Conversion
- The concept of Morphine Milligram Equivalent (MME) is crucial in understanding opioid conversion and managing opioid therapy effectively 3.
- MME is a measure used to calculate the equivalent dose of different opioids, allowing for safer and more effective prescribing practices.
- According to the CDC guideline for prescribing opioids for chronic pain, understanding MME is essential for primary care providers to initiate or continue opioids for chronic pain, select appropriate opioids, and determine dosage and duration 4.
Factors Influencing MME
- The efficacy of opioids such as morphine, pregabalin, gabapentin, and duloxetine can vary depending on the type of pain being treated, such as mechanical allodynia or neuroma pain 5.
- Studies have shown that combination therapy with opioids and other medications like gabapentin can enhance analgesic effects and may be beneficial for certain types of pain 6, 5.
- Patient-specific factors, including the presence of pain conditions, psychiatric disorders, and benzodiazepine prescription, can influence MME and should be considered when adjusting opioid doses 3.
Clinical Implications of MME
- Implementing multimodal analgesia protocols can lead to decreased inpatient and outpatient opioid use, as measured by MME, and may reduce the risks associated with long-term opioid therapy 7.
- The CDC guideline recommends careful assessment of the benefits and risks of opioid therapy, including the use of MME to guide dosing decisions and minimize the potential for abuse, dependence, and overdose 4.
- Further research is needed to fully understand the impact of MME on opioid conversion and to develop evidence-based guidelines for opioid prescribing practices 3, 7.