What is the appropriate conversion ratio from IV Dilaudid (hydromorphone) to a fentanyl patch?

IV Hydromorphone to Fentanyl Patch Conversion

When converting from IV hydromorphone to transdermal fentanyl patch, use a two-step process: first convert IV hydromorphone to IV morphine equivalent, then use the established conversion table to select the appropriate fentanyl patch strength.

Conversion Algorithm

Step 1: Calculate total daily IV hydromorphone dose

• Multiply the hourly IV hydromorphone dose by 24 to determine the total daily dose 1

Step 2: Convert IV hydromorphone to IV morphine equivalent

• Use the equianalgesic ratio where 1.5 mg IV hydromorphone = 10 mg IV morphine 1
• For example, 6 mg/day IV hydromorphone = 40 mg/day IV morphine 1

Step 3: Select appropriate fentanyl patch strength based on IV morphine equivalent

• Use the following conversion table from IV morphine to transdermal fentanyl 1:
  • 20 mg/day IV morphine = 25 mcg/h fentanyl patch 1
  • 40 mg/day IV morphine = 50 mcg/h fentanyl patch 1
  • 60 mg/day IV morphine = 75 mcg/h fentanyl patch 1
  • 80 mg/day IV morphine = 100 mcg/h fentanyl patch 1

Step 4: Dose adjustment for cross-tolerance

• If pain was well-controlled with IV hydromorphone, consider reducing the calculated fentanyl dose by 25-50% to account for incomplete cross-tolerance 1
• If pain was poorly controlled, use 100% of the calculated equianalgesic dose or consider increasing by 25% 1

Example Calculation

For a patient receiving 2 mg/h IV hydromorphone:

• Total daily dose: 2 mg/h × 24 h = 48 mg/day IV hydromorphone 1
• Convert to IV morphine equivalent: 48 mg IV hydromorphone ÷ 1.5 mg × 10 mg = 320 mg/day IV morphine 1
• Appropriate fentanyl patch: Multiple 100 mcg/h patches (since 80 mg/day IV morphine = 100 mcg/h) 1
• Consider dose reduction: If pain was well-controlled, reduce by 25-50% (150-240 mcg/h) 1

Important Clinical Considerations

• Provide breakthrough pain medication during the transition period, particularly during the first 8-24 hours as fentanyl levels reach steady state 1
• Pain should be relatively well-controlled on short-acting opioids before initiating the fentanyl patch 1
• Fentanyl patches are NOT recommended for unstable pain requiring frequent dose changes 1
• Use fentanyl patches only in patients who are opioid-tolerant 1
• Avoid application of heat (e.g., fever, heat lamps, electric blankets) as it accelerates fentanyl absorption 1

Monitoring and Adjustment

• Fentanyl patch reaches steady state after 2-3 days; adjust dosage based on breakthrough medication requirements after this period 1
• The fentanyl patch analgesic duration is usually 72 hours, but some patients require replacement every 48 hours 1
• Continue breakthrough medication once the patch dose is stabilized 1

Potential Pitfalls

• The conversion ratio between IV hydromorphone and transdermal fentanyl is not linear and may vary at higher doses 2, 3
• Studies suggest that at higher doses of opioids, lower conversion ratios may be needed 2, 3
• Individual patient variability necessitates close monitoring during conversion 1
• Respiratory depression risk is highest during the first 24-72 hours of transition 4