From the Guidelines
The morphine equivalent dose of oxycodone 20mg orally is 30mg.
Calculation
- The conversion factor for oxycodone is 1.5 as per the table in 1.
- To calculate the morphine equivalent dose, multiply the dose of oxycodone by the conversion factor: 20mg x 1.5 = 30mg.
Important Considerations
- The conversion factors are estimates and may not account for individual variability in genetics and pharmacokinetics 1.
- When converting opioids, the new opioid should be dosed at a substantially lower dose than the calculated morphine equivalent dose to avoid overdose due to incomplete cross-tolerance and individual variability in opioid pharmacokinetics 1.
- The morphine equivalent dose should not be used to determine the dose when converting one opioid to another, but rather as a guide for estimating the equivalent analgesic effect 1.
Clinical Relevance
- The calculation of morphine equivalent dose is crucial in clinical practice to ensure safe and effective pain management, particularly when switching between different opioids or rotating to a different opioid 1.
- It is essential to consider the individual patient's response to opioids and adjust the dose accordingly to minimize the risk of overdose or underdose 1.
The FDA Drug Labels for morphine (PO), oxycodone (PO) do not address this question.
From the Research
Morphine Equivalent Dose of Oxycodone
To determine the morphine equivalent dose of oxycodone 20mg orally, we need to consider the available evidence on the conversion ratio between oxycodone and morphine.
- The study by 2 suggests a ratio of 1:2 for oral oxycodone to oral morphine, implying that 20mg of oral oxycodone is equivalent to 40mg of oral morphine.
- In contrast, the study by 3 supports a 1:1 milligram conversion ratio for oral morphine and oral oxycodone, suggesting that 20mg of oral oxycodone is equivalent to 20mg of oral morphine.
- Another study by 4 used a 3:1 morphine:oxycodone oral dose ratio, which would imply that 20mg of oral oxycodone is equivalent to 60mg of oral morphine.
Key Findings
- The conversion ratio between oxycodone and morphine varies across studies, ranging from 1:1 to 1:2 to 3:1 (morphine:oxycodone).
- The study by 2 provides a commonly cited conversion ratio of 1:2, which would result in a morphine equivalent dose of 40mg for 20mg of oral oxycodone.
- However, other studies suggest different conversion ratios, highlighting the need for careful consideration of the specific context and patient population when converting between oxycodone and morphine.