Tramadol to Oxycodone Dosing Conversion
When converting from tramadol to oxycodone for pain management, use a conversion ratio of 7.5:1 (tramadol:oxycodone), which is derived from their respective morphine milligram equivalent (MME) conversion factors of 0.2 for tramadol and 1.5 for oxycodone.
Conversion Calculation Using MME
- According to the CDC Clinical Practice Guideline (2022), tramadol has an MME conversion factor of 0.2, while oxycodone has an MME conversion factor of 1.5 1
- This means:
- 100 mg of tramadol = 20 MME (100 × 0.2)
- 20 MME of oxycodone = 13.3 mg (20 ÷ 1.5)
- Therefore, 100 mg of tramadol is approximately equivalent to 13.3 mg of oxycodone, yielding a ratio of about 7.5:1 1
Practical Conversion Approach
- Start with a conservative dose when converting from tramadol to oxycodone 1
- For example:
- 200 mg daily tramadol ≈ 25-30 mg daily oxycodone
- 300 mg daily tramadol ≈ 40 mg daily oxycodone
- 400 mg daily tramadol (maximum recommended dose) ≈ 50-55 mg daily oxycodone 1
Important Considerations and Cautions
When converting between opioids, the new opioid should typically be dosed at a substantially lower dose than the calculated MME dose (approximately 25-50% reduction) to avoid overdose due to:
- Incomplete cross-tolerance between different opioids
- Individual variability in opioid pharmacokinetics 1
Equianalgesic dose conversions are only estimates and cannot account for individual variability in genetics and pharmacokinetics 1
Oxycodone is significantly more potent than tramadol:
- Oxycodone is considered 1.5 times as potent as morphine
- Tramadol is considered 0.2 times as potent as morphine (approximately one-tenth as potent as oxycodone) 1
Dosing Strategy
- For opioid-naïve patients, start with the lowest effective dose (5-10 mg oxycodone daily) 1
- For patients converting from tramadol:
- Begin with divided doses of oxycodone (typically 3-4 times daily for immediate-release formulations) 1
- Consider starting with immediate-release oxycodone for titration before transitioning to controlled-release formulations if needed 2
- Use caution when prescribing opioids at any dosage and generally avoid dosage increases when possible 1
Monitoring and Safety
- Before increasing total opioid dosage to ≥50 MME/day, carefully reassess evidence of individual benefits and risks 1
- If dose increases are necessary, increase by the smallest practical amount 1
- Monitor for adverse effects common to opioids, including nausea, vomiting, constipation, somnolence, dizziness, and pruritus 2
- Be aware that oxycodone carries a higher risk of adverse effects and potential for dependence compared to tramadol 3, 4
Special Populations
- For older adults (≥75 years) and those with hepatic or renal dysfunction, consider lower starting doses and slower titration 1
- For patients with chronic pain requiring long-term management, the lowest effective dose should be used 4
Remember that this conversion ratio is a guideline, and clinical response should guide subsequent dose adjustments while prioritizing patient safety and minimizing risk of adverse effects.