What is the conversion ratio from hydrocodone (opioid analgesic) to oxycodone (opioid analgesic) for pain management?

Hydrocodone to Oxycodone Conversion

When converting from hydrocodone to oxycodone, use a ratio of approximately 1:0.67 (or 1.5:1 in reverse), meaning 10 mg of hydrocodone equals approximately 6.7 mg of oxycodone, but always reduce the calculated dose by 25-50% to account for incomplete cross-tolerance. 1

Conversion Calculation Method

Using the CDC's morphine milligram equivalent (MME) conversion factors: 1

• Hydrocodone has a conversion factor of 1.0 (meaning 1 mg hydrocodone = 1 MME)
• Oxycodone has a conversion factor of 1.5 (meaning 1 mg oxycodone = 1.5 MME)

Step-by-Step Algorithm:

1. Calculate total daily hydrocodone dose - Add all hydrocodone doses taken in 24 hours 1

2. Convert to MME - Multiply hydrocodone dose by 1.0 (the dose stays the same in MME) 1

3. Calculate theoretical oxycodone equivalent - Divide the MME by 1.5 to get the oxycodone dose 1

   • Example: 30 mg hydrocodone daily = 30 MME ÷ 1.5 = 20 mg oxycodone daily

4. Apply safety reduction of 25-50% - This is the most critical step 1

   • If pain was well-controlled: reduce by 50% (use 10 mg oxycodone in above example)
   • If pain was poorly controlled: reduce by 25% (use 15 mg oxycodone in above example)

Critical Safety Considerations

Never use the calculated MME dose directly when converting between opioids - the CDC explicitly warns that equianalgesic conversions cannot account for incomplete cross-tolerance and individual pharmacokinetic variability. 1

Key Safety Points:

• Incomplete cross-tolerance means patients don't have full tolerance to the new opioid even if tolerant to the previous one, creating overdose risk 1

• Individual variability in genetics and pharmacokinetics makes conversions unpredictable 1, 2

• Always prescribe breakthrough medication during the conversion period, typically 10-15% of the total daily dose as needed every 2-4 hours 1

Common Clinical Scenarios

Example 1: Well-Controlled Pain

Patient on hydrocodone 10 mg four times daily (40 mg/day total):

• 40 mg hydrocodone = 40 MME
• 40 MME ÷ 1.5 = 26.7 mg oxycodone theoretical dose
• Apply 50% reduction: Start with 13-15 mg oxycodone daily (e.g., 5 mg three times daily) 1

Example 2: Poorly Controlled Pain

Same patient with inadequate pain relief:

• 40 mg hydrocodone = 40 MME
• 40 MME ÷ 1.5 = 26.7 mg oxycodone theoretical dose
• Apply 25% reduction: Start with 20 mg oxycodone daily (e.g., 5 mg four times daily or 10 mg twice daily if using extended-release) 1

Monitoring and Titration

Reassess within 24-48 hours of conversion to evaluate pain control and adverse effects 3

• Monitor for oversedation, respiratory depression, or inadequate analgesia 1
• Titrate based on breakthrough medication requirements 1, 3
• The peak respiratory depressant effect may occur at different times than peak analgesic effect 1

Important Caveats

Opioid rotation is indicated when the adverse effect/analgesic equation is skewed toward side effects despite aggressive adjuvant treatment 1

• Studies show 10-30% of patients on one opioid don't achieve successful outcomes but may respond better to another opioid 1
• The conversion ratio remains somewhat unpredictable due to asymmetric tolerance and different pharmacokinetic profiles 1, 4
• Research demonstrates significant variability in how clinicians perform these conversions, with large standard deviations in practice 2

Avoid dosage increases when possible - many patients don't experience benefit in pain or function from increasing opioid dosages but are exposed to progressive increases in risk 1