What are the equivalencies of different narcotics to morphine?

From the Guidelines

The most accurate and up-to-date equivalencies of different narcotics to morphine can be found in the 2022 CDC clinical practice guideline for prescribing opioids for pain, which provides a table of morphine milligram equivalent doses for commonly prescribed opioids. When considering the equivalencies of different narcotics to morphine, it's essential to prioritize the most recent and highest quality study, which in this case is the 2022 CDC guideline 1. The table provided in this guideline offers the following conversion factors:

• Codeine: 0.15
• Fentanyl transdermal (in mcg/hr): 2.4
• Hydrocodone: 1.0
• Hydromorphone: 5.0
• Methadone: 4.7
• Morphine: 1.0
• Oxycodone: 1.5
• Oxymorphone: 3.0
• Tapentadol: 0.4
• Tramadol: 0.2 Some key points to consider when using these conversion factors include:
• Multiply the dose for each opioid by the conversion factor to determine the dose in MMEs
• Equianalgesic dose conversions are only estimates and cannot account for individual variability in genetics and pharmacokinetics
• Do not use the calculated dose in MMEs to determine the doses to use when converting one opioid to another; when converting opioids, the new opioid is typically dosed at a substantially lower dose than the calculated MME dose to avoid overdose
• Use particular caution with methadone dose conversions because methadone has a long and variable half-life, and peak respiratory depressant effect occurs later and lasts longer than peak analgesic effect
• Use particular caution with transdermal fentanyl because it is dosed in mcg/hr instead of mg/day, and its absorption is affected by heat and other factors It's also important to note that other studies, such as the 2018 ESMO clinical practice guidelines for the management of cancer pain in adult patients, provide additional information on opioid conversion and management, but the 2022 CDC guideline is the most recent and highest quality study on this topic 1. In clinical practice, it's crucial to use these conversion factors with caution and to adjust the doses based on individual patient factors, including age, organ function, pain severity, and previous opioid exposure, to ensure adequate pain control while minimizing side effects. Some examples of equivalencies include:
• Hydrocodone 30mg = morphine 30mg
• Oxycodone 20mg = morphine 30mg
• Hydromorphone 6mg = morphine 30mg (using the conversion factor of 5.0)
• Fentanyl 12.5mcg/hr (transdermal) = morphine 30mg (using the conversion factor of 2.4) When converting between opioids, it's recommended to reduce the calculated equianalgesic dose by 25-50% to account for incomplete cross-tolerance, except when converting to methadone, which requires a 75-90% reduction. Patient monitoring after conversion is crucial to ensure adequate pain control while minimizing side effects like respiratory depression, sedation, and constipation.

From the FDA Drug Label

TABLE D*,† EQUIANALGESIC POTENCY CONVERSION Name | Equianalgesic Dose (mg) IM‡,§ | PO Morphine | 10 | 60 (30)¶ Hydromorphone (Dilaudid®)| 1.5 | 7.5 Methadone (Dolophine®) | 10 | 20 Oxycodone | 15 | 30 Levorphanol (Levo-Dromoran®) | 2 | 4 Oxymorphone (Numorphan®) | 1 | 10 (PR) Meperidine (Demerol®) | 75 | — Codeine | 130 | 200

The equivalencies of different narcotics to morphine are as follows:

• Hydromorphone (Dilaudid): 1.5 mg IM or 7.5 mg PO is equivalent to 10 mg of morphine
• Methadone (Dolophine): 10 mg IM or 20 mg PO is equivalent to 10 mg of morphine
• Oxycodone: 15 mg IM or 30 mg PO is equivalent to 10 mg of morphine
• Levorphanol (Levo-Dromoran): 2 mg IM or 4 mg PO is equivalent to 10 mg of morphine
• Oxymorphone (Numorphan): 1 mg IM or 10 mg PR is equivalent to 10 mg of morphine
• Meperidine (Demerol): 75 mg IM is equivalent to 10 mg of morphine
• Codeine: 130 mg IM or 200 mg PO is equivalent to 10 mg of morphine
• Buprenorphine: 0.3 mg is approximately equivalent to 10 mg morphine sulfate in analgesic and respiratory depressant effects in adults 2 Note that these equivalencies are based on the information provided in the drug labels and may not be applicable in all situations. 3

From the Research

Narcotic Equivalencies to Morphine

The equivalencies of different narcotics to morphine can be summarized as follows:

• The study 4 found that the mean morphine equivalent (MEQ) doses for fentanyl, hydrocodone, hydromorphone, methadone, and oxycodone were 176 mg, 88 mg, 192 mg, 193 mg, and 173 mg, respectively.
• The study 5 found that there was no correlation between high morphine equivalent doses and methadone doses at dose stabilization after opioid rotation.
• The study 6 found that the potency relationship between oxycodone, morphine, and hydrocodone was oxycodone > morphine > hydrocodone.
• The study 7 found that the analgesic effect of morphine and oxycodone was estimated to be equal, but the relative potency of oxycodone was variably higher.
• The study 8 developed a comprehensive oral morphine equivalent (OME) conversion table that can be used by researchers to calculate OMEs in a consistent and systematic way.

Comparison of Narcotic Equivalencies

A comparison of the narcotic equivalencies to morphine is shown below:

• Fentanyl: 176 mg MEQ 4
• Hydrocodone: 88 mg MEQ 4
• Hydromorphone: 192 mg MEQ 4
• Methadone: 193 mg MEQ 4, no correlation with high morphine equivalent doses 5
• Oxycodone: 173 mg MEQ 4, variably higher relative potency than morphine 7
• Oxycodone vs. Morphine vs. Hydrocodone: oxycodone > morphine > hydrocodone 6

Key Findings

Key findings from the studies include:

• Significant variation in mean opioid conversions to MEQ doses within each profession type 4
• No universal method exists that allows each of the five studied opioids to be accurately and consistently converted to another opioid (i.e., morphine) 4
• The use of the OME metric appears optimal for opioid utilisation studies as it facilitates both interpretation and comparison between opioids and geographical locations 8