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Opioid Conversion (Drug to Drug)

Converts a total daily opioid dose to an equianalgesic dose of another opioid via morphine milligram equivalents (CDC 2022 factors: oxycodone 1.5, hydromorphone 5, hydrocodone 1, oxymorphone 3, tapentadol 0.4, tramadol 0.2, codeine 0.15, fentanyl patch 2.4 per mcg/h). Reduce the calculated dose by 25–50% for incomplete cross-tolerance. Methadone is excluded.

  • Current opioid (route): Oral morphine (factor 1); Oral oxycodone (factor 1.5); Oral hydrocodone (factor 1); Oral hydromorphone (factor 5); Oral oxymorphone (factor 3); Oral codeine (factor 0.15); Oral dihydrocodeine (factor 0.25); Oral tramadol (factor 0.2); Oral tapentadol (factor 0.4); Transdermal fentanyl (factor 2.4 per mcg/h); Methadone (not supported)
  • Current total daily dose (mg/day; fentanyl patch: mcg/h)
  • Target opioid (route): Oral morphine (factor 1); Oral oxycodone (factor 1.5); Oral hydrocodone (factor 1); Oral hydromorphone (factor 5); Oral oxymorphone (factor 3); Oral codeine (factor 0.15); Oral dihydrocodeine (factor 0.25); Oral tramadol (factor 0.2); Oral tapentadol (factor 0.4); Transdermal fentanyl (factor 2.4 per mcg/h); Methadone (not supported)
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Interpretation

ResultMeaning
Equianalgesic doseTheoretical equivalent at full cross-tolerance
Reduce 25–50%Usual starting dose for the new opioid; nearer 50% in older, frail or opioid-naive-equivalent patients

Formula

MME/day = current daily dose × factor(current). Target daily dose = MME ÷ factor(target). CDC 2022 factors: codeine 0.15, dihydrocodeine 0.25, fentanyl transdermal 2.4 (per mcg/h), hydrocodone 1, hydromorphone 5, morphine 1, oxycodone 1.5, oxymorphone 3, tapentadol 0.4, tramadol 0.2 (all oral except fentanyl).

Clinical pearls

  • CDC states its MME factors are for risk estimation and are not intended as dose-conversion tables; individual response varies, so reduce 25–50% and titrate with rescue doses.
  • Only oral routes (plus transdermal fentanyl) are covered; parenteral conversions (e.g. IV morphine ≈ 3× oral) need institution-specific tables.
  • Methadone and buprenorphine conversions are not linear and need specialist protocols.

Examples

convert oxycodone 30 mg/day to hydromorphonemorphine 60 mg per day to fentanyl patchopioid rotation hydrocodone 40 mg daily to oxycodone

FAQ

How do you convert oxycodone to hydromorphone?

Convert to MME (oxycodone × 1.5), divide by the hydromorphone factor (5), then reduce 25–50%. Oxycodone 30 mg/day ≈ 45 MME ≈ hydromorphone 9 mg/day, so start about 4.5–6.75 mg/day.

Why reduce the dose when switching opioids?

Tolerance to one opioid is not fully shared with another (incomplete cross-tolerance), so the equianalgesic dose can overshoot.

Evidence

  1. Dowell D et al. CDC Clinical Practice Guideline for Prescribing Opioids for Pain — United States, 2022. MMWR Recomm Rep 2022;71(3):1–95.

Pharmacology & Dosing · Reviewed 2026-10-14 · Methodology