Calculators · Pharmacology · Conversion

Morphine milligram equivalents (MME/day)

Also called MME calculator, opioid conversion, oral morphine equivalent, OME

Total daily opioid dose in morphine milligram equivalents using the CDC 2022 conversion factors, to gauge overdose risk.

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Check the values entered.

Formula and scoring

MME/day = Σ (daily dose × factor). Factors (CDC 2022): codeine 0.15, fentanyl patch 2.4 per mcg/hr, hydrocodone 1, hydromorphone 5, morphine 1, oxycodone 1.5, oxymorphone 3, tapentadol 0.4, tramadol 0.2.

Exam and ward pearls

  • Fentanyl patch is entered in mcg/hr, not mg/day: a 25 mcg/hr patch = 60 MME/day.
  • Tramadol (factor 0.2) and tapentadol (0.4) have non-opioid actions too; CDC notes it is unknown whether their overdose risk rises with dose the way pure µ-agonists do.
  • Overdose risk roughly doubles at 50 to <100 MME/day compared with <20 MME/day (CDC 2022 evidence review).

When not to rely on it

  • Do NOT convert methadone with a single factor: its half-life is long and variable, and its peak respiratory depression comes later and lasts longer than its peak analgesia (CDC 2022). Get specialist or palliative-care advice.
  • Buprenorphine is excluded because of partial agonism and ceiling effect.
  • Never use MME to convert from one opioid to another; start the new opioid at a substantially lower dose for incomplete cross-tolerance.
  • Not for management of opioid use disorder.

Source

  1. Dowell D, Ragan KR, Jones CM, Baldwin GT, Chou R. CDC Clinical Practice Guideline for Prescribing Opioids for Pain - United States, 2022. MMWR Recomm Rep. 2022;71(3):1-95. doi:10.15585/mmwr.rr7103a1 · PMID 36327391

Formula and cut-offs checked against these sources on 8 Nov 2026. Educational tool for clinicians; it does not replace clinical judgement.

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