⚠ Estimates only. Verify every conversion. Equianalgesic values vary substantially between patients and sources. Always reduce for incomplete cross-tolerance, reassess within 24 h, and never convert opioid-naïve patients to a long-acting opioid. Confirm with a second clinician for high doses.
CDC MME Factors & Oral Equianalgesic Estimates
Opioid (oral)
CDC MME factor
≈ Dose equal to 30 mg oral morphine
Morphine
1
30 mg
Hydrocodone
1
30 mg
Oxycodone
1.5
20 mg
Hydromorphone
5
~6 mg*
Oxymorphone
3
10 mg†
Codeine
0.15
~200 mg
Tramadol
0.1
~300 mg (weak; ~400 mg/day ceiling)
Fentanyl patch (mcg/h)
2.4
25 mcg/h ≈ 60 mg/day OME
Methadone
4.7 (variable)
see danger box below
Per the CDC 2022 MME conversion factors (dose × factor = daily MME; risk rises at ≥50 MME/day, extra caution ≥90). MME factors apply to oral opioids only.
*Hydromorphone: CDC uses a factor of 5 (→ ~6 mg ≈ 30 mg morphine); traditional bedside equianalgesic tables often cite ~7.5 mg (4:1). Known discrepancy: reduce and reassess regardless.
†Oral oxymorphone (Opana ER) was withdrawn from the US market in 2017 and injectable oxymorphone is not generally available; shown for MME/record completeness.
Parenteral anchors (not part of CDC oral MME): morphine 10 mg IV ≈ 30 mg PO (~3:1); hydromorphone 1.5 mg IV ≈ 10 mg IV morphine; fentanyl 100 mcg IV ≈ 10 mg IV morphine (acute).
The 5-Step Method
1
Total the last 24 h of all opioids the patient actually took (scheduled + breakthrough).
2
Convert to oral morphine equivalents (OME) using the table above.
3
Convert OME to the target opioid.
4
Reduce 25–50% for incomplete cross-tolerance (larger reduction if elderly/frail or pain well-controlled; smaller if pain is severe and uncontrolled).
5
Schedule + breakthrough: divide into the dosing interval; give breakthrough at ~10–15% of the total daily dose q1–4h PRN. Reassess within 24 h and titrate.
🛑 Special-Case Danger Zones
Methadone:non-linear, dose-dependent conversion (ratio rises as OME rises), long/variable half-life, QT prolongation. Do not use simple equianalgesic ratios. Specialist / experienced clinician only.
Fentanyl patch:~25 mcg/h ≈ 60 mg oral morphine/day (published ratios range 80:1–150:1). Do not use standard tables to convert OFF a patch: they overestimate the new opioid and can cause overdose. Not for opioid-naïve or acute pain; residual effect persists ~17–24 h after removal.
Meperidine:avoid for chronic pain (normeperidine neurotoxicity/seizures).
Pearls
🩸
Renal/hepatic impairment, elderly, OSA: reduce further and go slow. Hydromorphone/oxycodone often preferred over morphine in renal dysfunction (morphine's active metabolites accumulate).
💉
Co-prescribe naloxone and counsel on sedation/respiratory depression, especially with benzodiazepine co-use or ≥50 MME/day.