What Are MMEs? Morphine Milligram Equivalents Explained
How clinicians standardize and compare opioid doses safely.
Not all opioids are equal in strength. A 10 mg dose of oxycodone is more potent than 10 mg of codeine. To compare and combine opioid prescriptions safely, clinicians use morphine milligram equivalents (MME)—a standardized measure of opioid potency relative to morphine.

Why MMEs Matter
MMEs help clinicians assess overdose risk, monitor for opioid use disorder, and guide tapering decisions. Higher daily MMEs are associated with increased risks of respiratory depression, falls, constipation, and dependence.
Common Conversion Factors
| Opioid | Conversion Factor (to morphine) |
|---|---|
| Codeine | 0.15 |
| Tramadol | 0.2 |
| Morphine | 1.0 |
| Oxycodone | 1.5 |
| Hydrocodone | 1.0 |
| Fentanyl (transdermal) | See specific mcg/hr tables |
Safety Thresholds
The CDC and many guidelines caution that doses above 50 MME per day increase risk significantly, and doses above 90 MME per day should be carefully justified and monitored. These are guidelines, not absolute rules—individual patient factors matter.
Limitations
MME conversions are estimates. Patient genetics, kidney/liver function, concurrent medications (especially benzodiazepines), and tolerance all affect real-world risk. Always consult a prescriber or pharmacist before changing opioid regimens.
Use our free MME calculator to estimate daily morphine equivalents.
Book a telemedicine consultation or lab review with Dr. Taimoor Asghar.