MME is widely used across healthcare settings to assess opioid potency and use, facilitate further discussions with patients, and aid in clinical decision-making. However, the concept of MME has limitations, as it relies on many factors and assumptions that do not always hold true across patient populations or clinical scenarios. Understanding how MME should be applied requires an appreciation of its underlying principles, as well as a recognition of its limitations.
MME & Regulatory Compliance
Many PDMPs have adopted MME thresholds to guide prescribing limits, opioid stewardship programs, and risk mitigation strategies.
Conversion tables serve as the backbone of MME calculations, providing a comparative framework for assessing opioid exposure across different agents. However, these tables are derived from population-level data and fail to account for significant variability in factors such as opioid metabolism, receptor sensitivity, and clinical response. The conversion ratios used in MME calculations can be highly context-dependent, influenced by factors such as acute versus chronic opioid use, interacting drugs, the prescription instructions, and the way a patient actually takes their prescription.
Generally, our MME values follow the CDC’s MME conversion factors. For the vast majority of drugs, providers should be able to perform the standard MME calculation to arrive at the Daily MME value that appears on the Patient Report.
Due to this, Bamboo Health has adopted a standard approach to MMEs across all PDMPs:
1. Assign an MME conversion value to all opioids reported to the PDMP
2. Calculate daily MME
a. Buprenorphine is excluded from displayed MME calculations
b. The summary section of the Patient Report includes information on:
i. Narcotics displayed in MMEs (excluding buprenorphine)
ii. Buprenorphine displayed in mg/day
c. The MME/D column in the Prescriptions section of a Patient Report displays mg/day for buprenorphine on applicable prescriptions.
d. Buprenorphine is excluded from the MME/D column in CSV/Excel spreadsheet files.
The CDC recommends a sliding scale conversion for MME in clinical practice but publishes a static conversion factor for methadone in the conversion factor file that is used for PDMPs. In accordance with the CDC's historical guidance, Bamboo Health uses a static value of 4.7 for methadone MME conversions. While this doesn't align with the sliding scale for clinical practice, it is in line with the CDC's historical guidance.
| The CDC's historical guidance can be found at CDC Guideline for Prescribing Opioids for Chronic Pain - United States, 2016, Recommendations and Reports / March 18, 2016 / 65(1);1-49 [https://www.cdc.gov/mmwr/volumes/71/rr/rr7103a1.htm] |
By applying this standardized approach, PDMPs can provide clinically meaningful, reproducible, and contextually appropriate opioid utilization data, ensuring that prescribers and dispensers receive valuable insights without an over-reliance on numerical MME thresholds.
Additionally, when a prescriber's directions allow for multiple dosage options, such as 1 to 2 tablets every 4 to 6 hours, the maximum dosage is assumed since that is consistent with the prescriber directions. Furthermore, Bamboo Health cannot modify submission data since our solution has no way of tracking these multiple dosage options; it is all circumspect. Our calculations report on what the dispenser reports to the PDMP as the dispensed quantity by the prescriber and not what is consumed by the patient.
| Please see the MME Conversion Factors table located at the bottom of the article for additional information on conversion factors. |
Prescribing Complexities and Real-World Variability
MME calculations inherently assume that medications are taken precisely as prescribed, but real-world opioid use often deviates from this assumption. Patients may take more or less medication than directed, impacting both the intended effect and the validity of MME calculations. For example, when opioids are prescribed on an as-needed basis (PRN), pharmacy systems typically assume the maximum allowable dose is consumed when calculating the days' supply and cumulative MME.
Certain opioid formulations may be used differently from manufacturer recommendations, such as fentanyl patches being rotated every two days instead of every three. In practice, PRN usage can vary widely, meaning a submitter can write a prescription for use that differs (e.g., fentanyl patches) from its intended use. Therefore, the calculated MME may significantly overestimate actual opioid exposure.
For example, the MME for 15 patches of fentanyl is 50% greater than 10 patches of fentanyl. This is because when changing fentanyl patches every 3 days (10 patches/month), we assume that each patch is worn for 72 hours (3 days) and that a prescription for 10 patches covers 30 days. However, when a patient changes fentanyl patches every 2 days (15 patches/month), we assume that each patch is worn for 72 hours (3 days - we have no patient directions) and that 1.5 patches are worn continuously or that some days 2 patches are worn simultaneously. Thus, a prescription for 15 patches covering 30 days produces an MME 50% higher. The MME is higher with 15 patches because the patient appears to be consuming the total fentanyl delivered to them in 20 days.
In other words, because (i) we do not receive the prescriber’s directions to the patient, and (ii) we conclude that the patient will use all of the available medication in the Days Supply submitted (in this example, 3 days of medication in each patch), the effect dose is 1.5 X higher when changing patches every 2 days. When patches are being changed more frequently than the manufacturer’s recommendation, there is still 33% of the medication remaining in the patch at the time of disposal. By discarding the patch early and applying a fresh patch, the patient has a third more medication available that could be used. The patient may even keep wearing the first patch and add another, which is why the patient’s MME is higher (they have 15 patches to use in 30 days instead of 10).
Additional complexity arises in situations where lost or stolen medications must be replaced, as healthcare systems continue to count the initial prescription in MME calculations, potentially misrepresenting actual opioid exposure. These assumptions and discrepancies underscore the limitations of using MME as a rigid metric and highlight the need for clinical judgment in its interpretation.
Therefore, rather than viewing MME as a universally applicable metric, it is better to approach MME through the lens of specific uses cases.