Opioid MME Calculator (Morphine Milligram Equivalents)
Calculate total daily morphine milligram equivalents (MME) to assess opioid overdose risk. Based on CDC opioid prescribing guidelines.
Calculate Opioid MME
Select the opioid medication
MME Conversion Factors
CDC MME Thresholds
Morphine Milligram Equivalent
Enter values to calculate
About This Calculator
The Morphine Milligram Equivalent (MME) Calculator helps clinicians assess the total daily opioid dose by converting different opioids to a standardized morphine equivalent dose.
This is essential for: • Identifying patients at higher risk of opioid overdose • Guiding opioid prescribing decisions • Monitoring patients on chronic opioid therapy • Facilitating opioid tapering and rotation
The CDC guidelines recommend caution when prescribing ≥50 MME/day and avoiding ≥90 MME/day, or carefully justifying the decision to do so.
Formula
MME = Daily Opioid Dose × Conversion FactorEach opioid has a specific conversion factor relative to morphine: • Morphine, Hydrocodone: 1 • Oxycodone: 1.5 • Hydromorphone: 4 • Oxymorphone: 3 • Fentanyl patch: 2.4 (per mcg/hr) • Codeine: 0.15 • Tramadol: 0.1 • Tapentadol: 0.4 • Methadone: Variable (4-12) based on dose range
Clinical Considerations
- •These conversion factors are approximations for clinical reference only
- •Individual patient factors may significantly affect opioid response
- •Methadone conversions are particularly complex - consult pain specialist
- •Do not use for acute pain conversions or opioid rotation calculations
- •Concurrent benzodiazepines significantly increase overdose risk at any MME level
Limitations
- •Conversion factors may vary between sources
- •Does not account for incomplete cross-tolerance in opioid rotation
- •Not validated for patients with significant tolerance
- •Fentanyl patch conversion assumes steady-state levels
- •Does not include all available opioid formulations
Interpretation Guide
| Range | Classification | Recommendation |
|---|---|---|
| <-49 | Low Risk | Continue current therapy with routine monitoring. Re-evaluate periodically. |
| 50-89 | Moderate Risk | Implement additional precautions. Consider naloxone prescription. Evaluate for opioid use disorder. |
| 90-+ | High Risk | Carefully justify continuation. Prescribe naloxone. Consider specialist consultation. Discuss risks with patient. |
Frequently Asked Questions
What is MME and why is it important?
Morphine Milligram Equivalent (MME) is a standardized measure that allows comparison of different opioid medications. It helps identify patients at risk for overdose - the CDC found that patients receiving ≥50 MME/day have twice the risk of overdose compared to those receiving <20 MME/day.
What are the CDC MME thresholds?
The CDC recommends: <50 MME/day is generally safer, 50-89 MME/day requires additional precautions and consideration of naloxone, ≥90 MME/day should be avoided unless carefully justified. These thresholds apply to opioid-naive or non-tolerant patients.
Why does methadone have variable conversion factors?
Methadone has unique pharmacokinetics with a long, variable half-life. Higher doses of methadone are proportionally more potent, so the MME conversion factor increases with the daily methadone dose (4× for 1-20mg, up to 12× for ≥61mg daily).
Should I add up MME from multiple opioids?
Yes, for patients taking multiple opioids, calculate the MME for each medication and add them together. The total daily MME is what determines overdose risk according to CDC guidelines.
What factors increase overdose risk beyond MME?
Additional risk factors include: concurrent benzodiazepines or other CNS depressants, sleep apnea, renal or hepatic impairment, older age, history of substance use disorder, and mental health conditions.
References
1. Dowell D, Haegerich TM, Chou R. CDC Guideline for Prescribing Opioids for Chronic Pain. MMWR Recomm Rep. 2016
View Source →2. Dowell D, Ragan KR, Jones CM, et al.. CDC Clinical Practice Guideline for Prescribing Opioids for Pain (2022 Update). MMWR Recomm Rep. 2022
View Source →3. CDC. Calculating Total Daily Dose of Opioids for Safer Dosage. CDC Opioid Prescribing Guidelines. 2023
View Source →Last updated: 2024-12-01
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