Table 2.

Classification of Opioid Medications and Morphine Equivalent Conversion Factors per Milligram of Opioid*

Major GroupType of OpioidMorphine Equivalent Conversion Factor/Milligram of Opioid
Short-acting, non-schedule IIPropoxyphene (with or without aspirin/acetaminophen/ibuprofen)0.23
Codeine + acetaminophen, ibuprofen, or aspirin0.15
Hydrocodone + acetaminophen, ibuprofen, aspirin, or homatropine1.00
Tramadol with or without aspirin0.10
Butalbital and codeine (with or without aspirin, ibuprofen, acetaminophen)0.15
Dihydrocodeine (with or without aspirin, ibuprofen, acetaminophen)0.25
Pentazocine (with or without aspirin, ibuprofen, acetaminophen)0.37
Short-acting, schedule IIMorphine sulfate1.00
Codeine sulfate0.15
Oxycodone (with or without aspirin, ibuprofen, acetaminophen)1.50
Meperidine hydrochloride0.10
Fentanyl citrate transmucosal0.125
Long-acting, schedule IIMorphine sulfate sustained release1.00
Fentanyl transdermal2.40
Levorphanol tartrate11.0
Oxycodone HCl controlled release1.50
  • * Opioids delivered by pill, capsule, liquid, transdermal patch, and transmucosal administration were included. Opioids formulated for administration by injection or suppository were not included.

  • Transmucosal fentanyl conversion to morphine equivalents assumes 50% bioavailability of transmucosal fentanyl, and 100-μg transmucosal fentanyl is equivalent to 12.5 to 15 mg of oral morphine.

  • Transdermal fentanyl conversion to morphine equivalent is based on the assumption that one patch delivers the dispensed micrograms/hour over a 24-hour day and remains in place for 3 days.

  • Adapted from Von Korff M, Saunders K, Ray GT, et al. De facto long-term opioid therapy for noncancer pain. Clin J Pain 2008;24:521–7.19.