What is the conversion ratio from intravenous (IV) hydromorphone to oral oxycodone for a patient?

IV Hydromorphone to Oral Oxycodone Conversion

For converting IV hydromorphone to oral oxycodone, use a ratio of approximately 1:20 (1 mg IV hydromorphone = 20 mg oral oxycodone), then reduce the calculated dose by 25-50% to account for incomplete cross-tolerance if pain was well-controlled. 1

Conversion Algorithm

The National Comprehensive Cancer Network (NCCN) provides a two-step conversion process that should be followed systematically 1:

Step 1: Calculate the Morphine Equivalent

• Convert IV hydromorphone to oral morphine equivalent using a 1:40 ratio 1
• Example: 1.5 mg IV hydromorphone = 60 mg oral morphine equivalent per day 1

Step 2: Convert to Oral Oxycodone

• Apply the oral morphine to oral oxycodone ratio of 2:1 1
• Example: 60 mg oral morphine = 30 mg oral oxycodone 1
• This yields the direct conversion ratio of approximately 1:20 from IV hydromorphone to oral oxycodone

Step 3: Apply Incomplete Cross-Tolerance Reduction

• If pain was well-controlled on IV hydromorphone: Reduce the calculated oral oxycodone dose by 25-50%, resulting in 15-22.5 mg oral oxycodone in the example above 1
• If pain was poorly controlled: Use 100% of the calculated dose (30 mg) or increase by 25% 1

Supporting Evidence and Nuances

The conversion ratio is supported by multiple lines of evidence:

• A prospective study of 247 cancer patients rotating from IV hydromorphone to oral morphine or oxycodone found a median conversion ratio of 11.46:1 from IV hydromorphone to oral morphine equivalent daily dose (MEDD) 2
• This study noted that patients receiving ≥30 mg/day of IV hydromorphone may require a lower conversion ratio (9.86:1) compared to those on <30 mg/day (11.54:1) 2
• The oral morphine to oral oxycodone ratio of approximately 1.5-2:1 is consistently supported across systematic reviews 3

Critical Safety Considerations

Monitoring Requirements

• Reassess pain control and adverse effects within 24 hours after conversion, as steady state is reached within this timeframe 1
• Provide breakthrough doses equivalent to 10-20% of the total 24-hour opioid dose 1

Prophylactic Measures

• Institute a prophylactic bowel regimen with stimulant laxatives in all patients, as constipation is universal with opioid therapy 1

Special Populations Requiring Dose Reduction

• Renal impairment: Start with one-fourth to one-half the calculated dose 1
• Hepatic impairment: Reduce the initial dose by 25-50% 1

Common Pitfalls to Avoid

• Do not use simple multiplication factors without accounting for incomplete cross-tolerance - this is the most common cause of overdosing during opioid rotation 1
• Do not apply the same conversion ratio for high-dose patients - those on ≥30 mg/day IV hydromorphone may need lower ratios to avoid overdosing 2
• Do not forget that the 1:20 ratio represents the calculated dose before cross-tolerance reduction - always apply the 25-50% reduction for well-controlled pain 1