What is the equivalent oral dose of oxycodone (oxycodone) for a patient taking 25 micrograms (mcg) of fentanyl (fentanyl)?

Fentanyl 25 mcg/hr Transdermal Patch Equivalence to Oral Oxycodone

A 25 mcg/hr transdermal fentanyl patch is equivalent to approximately 60 mg of oral oxycodone per day.

Conversion Methodology

The conversion requires a two-step process using oral morphine as the intermediary opioid:

Step 1: Convert Fentanyl to Oral Morphine

• 25 mcg/hr transdermal fentanyl = 60 mg/day oral morphine 1, 2, 3
• This is the standard conversion ratio established by the National Comprehensive Cancer Network and FDA labeling 1, 3

Step 2: Convert Oral Morphine to Oral Oxycodone

• Using equianalgesic conversion tables, 60 mg/day oral morphine = 30-67 mg/day oral oxycodone 3
• The FDA conversion table specifically lists 30-67 mg/day oral oxycodone as equivalent to the morphine dose that converts to a 25 mcg/hr fentanyl patch 3
• The midpoint of this range is approximately 60 mg/day oral oxycodone

Direct Conversion Table

Based on FDA labeling and NCCN guidelines 1, 3:

• 25 mcg/hr fentanyl patch → 60 mg/day oral oxycodone
• 50 mcg/hr fentanyl patch → 120 mg/day oral oxycodone
• 75 mcg/hr fentanyl patch → 180 mg/day oral oxycodone
• 100 mcg/hr fentanyl patch → 240 mg/day oral oxycodone

Critical Safety Considerations

Dose reduction for incomplete cross-tolerance:

• When converting FROM fentanyl TO oxycodone, reduce the calculated equianalgesic dose by 25-50% to account for incomplete cross-tolerance and patient variability 1, 4
• This means starting with 30-45 mg/day oral oxycodone rather than the full 60 mg equivalent 1

Important caveat:

• The FDA explicitly warns that conversion tables for switching TO fentanyl are conservative and should NOT be used in reverse when converting FROM fentanyl to other opioids, as this can lead to overestimation and overdose 3
• Therefore, always reduce the calculated dose by 25-50% when converting from fentanyl to oxycodone 1

Practical Application

For a patient on a 25 mcg/hr fentanyl patch switching to oral oxycodone:

1. Calculate the theoretical equivalent: 60 mg/day oral oxycodone 3
2. Reduce by 25-50% for safety: Start with 30-45 mg/day oral oxycodone 1
3. Divide into appropriate dosing intervals (e.g., 15 mg every 12 hours for extended-release, or 10 mg every 8 hours for immediate-release) 1
4. Provide immediate-release opioid for breakthrough pain at 10-20% of total daily dose 2
5. Monitor closely and titrate upward as needed based on pain control 1, 3

Additional Monitoring Considerations

• Fentanyl has a mean half-life of approximately 17 hours after patch removal, so residual fentanyl will continue providing analgesia during the first 12-24 hours of conversion 3
• Patients require monitoring for at least 24 hours after conversion due to this prolonged elimination 3
• The wide variation in conversion ratios reported in clinical practice (standard deviations of ±117 mg for fentanyl conversions) emphasizes the need for individualized dose titration 5