Equations for Calculating MMEs


What we are studying

There is no standard or accepted method in the literature for calculating average daily milligrams of morphine equivalents (MME). MMEs are a way to standardize across opioids of different potencies in epidemiology studies. In particular, overlapping prescriptions change the picture of MME if they are not accounted for properly.

There is a belief that 90 MME/day is a threshold for overdose risk in patients treated with opioids, perpetuated by the CDC Guideline for Prescribing Opioids for Chronic Pain. However, the Food and Drug Administration has pointed out that there is actually a gradient of risk and the concept of a 90 MME/day threshold is an artifact of how studies measured opioid use.

Consider the following prescriber instructions: This month, the patient should take one 30mg ER oxycodone twice-a-day for around-the-clock pain for 30 days, AND one 5mg oxycodone twice a day as needed for breakthrough pain. Both prescriptions are to be dispensed on the first day of the month. Across 3 common published MME calculation methods, this patient could be at 53 MME/day, 76 MME/day, or 94 MME/day. Which one is correct?

Watch Nabarun Dasgupta give a walk through on this process of using equations to calculate MMEs:

Why it matters

Health insurers, lawmakers, clinical policymakers, and others are using 90 MME/day to limit patient benefits or prescriber practice.

For example, one state Medicaid policy reads: “for chronic non-cancer pain beneficiaries receiving an opioid… the total daily MME allowed limit will be ≤90 MME/day.”


How we are studying it

We are reviewing published studies to identify different formulae used to calculate average daily MME. We are generating the mathematical equations covering the different methods. We are doing simulations to see how the different definitions impact whether a prescription is considered “high-dose” or not. We are testing the equations in real world dispensing data.

How to use the results

All the code and equations are being made public so others can explicitly decide which to use for research studied involving daily MME.

Who is conducting and supporting the study

This study is led by Nabarun Dasgupta at the University of North Carolina. Funding for this project comes from the United States Food and Drug Administration. Studies at the Opioid Data Lab are conducted by independent researchers and do not necessarily represent the views of funders or partners. We are grateful to generations of taxpayers in North Carolina for supporting public universities. We are also grateful to US taxpayers for safeguarding public health by supporting FDA and this research project.

Nabarun Dasgupta
Epidemiologist, Factotum