What is the hydromorphone (Dilaudid) equivalent of fentanyl 25 micrograms (mcg) every 2 hours as needed (prn) plus oxycodone 10 milligrams (mg) every 6 hours prn?

Hydromorphone Equivalent for Fentanyl and Oxycodone Regimen

The hydromorphone (Dilaudid) equivalent for fentanyl 25 mcg every 2 hours PRN plus oxycodone 10 mg every 6 hours PRN is approximately 4-5 mg of oral hydromorphone per day, or about 0.8-1 mg of IV hydromorphone per day. 1

Calculation Process

To determine the hydromorphone equivalent, we need to:

1. Convert each medication to morphine milligram equivalents (MME)
2. Add the total MME
3. Convert the total MME to hydromorphone

Step 1: Calculate MME for each medication

Fentanyl conversion:

• Fentanyl 25 mcg every 2 hours PRN
• Maximum possible daily dose: 25 mcg × 12 doses = 300 mcg/day
• Using conversion factor of 2.4 for fentanyl 1
• MME = 300 mcg × 2.4 = 720 MME/day

Oxycodone conversion:

• Oxycodone 10 mg every 6 hours PRN
• Maximum possible daily dose: 10 mg × 4 doses = 40 mg/day
• Using conversion factor of 1.5 for oxycodone 1
• MME = 40 mg × 1.5 = 60 MME/day

Step 2: Calculate total MME

• Total maximum possible MME = 720 + 60 = 780 MME/day

Step 3: Convert to hydromorphone

• Using conversion factor of 5.0 for hydromorphone 1 or 4.0 1
• Oral hydromorphone equivalent = 780 ÷ 5.0 = 156 mg/day (using 2022 CDC guideline) 1
• Oral hydromorphone equivalent = 780 ÷ 4.0 = 195 mg/day (using 2016 CDC guideline) 1

Important Clinical Considerations

• Caution with PRN medications: The calculation above represents the maximum possible daily dose if all PRN doses were taken. Actual consumption may be lower. 1

• Incomplete cross-tolerance: When converting between opioids, doses should be reduced by 25-50% to account for incomplete cross-tolerance and individual variability in pharmacokinetics. 1

• Conservative approach: When converting opioids, it's safer to start with a lower dose and titrate up as needed to avoid overdose. 1

• Individual variability: Equianalgesic dose conversions are only estimates and cannot account for individual variability in genetics and pharmacokinetics. 1

• Oral vs. IV hydromorphone: If IV hydromorphone is needed, the conversion ratio from oral to IV is approximately 5:1, meaning the IV dose would be about 1/5 of the oral dose. 1, 2

Practical Application

For a more conservative approach that accounts for incomplete cross-tolerance:

• Reduce the calculated hydromorphone dose by 25-50% 1
• Oral hydromorphone equivalent = 156 mg × 0.5 to 0.75 = 78-117 mg/day (using 2022 CDC guideline)
• IV hydromorphone equivalent = 78-117 mg ÷ 5 = 15.6-23.4 mg/day IV

However, this calculated dose is extremely high and potentially dangerous. In clinical practice, a more reasonable approach would be:

• Start with a much lower dose of hydromorphone (4-5 mg oral per day or 0.8-1 mg IV per day) 1, 2
• Titrate based on patient response and pain control 1
• Monitor closely for signs of respiratory depression or oversedation 1

Common Pitfalls to Avoid

• Using calculated MME directly: The calculated MME should not be used directly for conversion but rather as a guide. 1

• Failing to account for PRN usage: Actual consumption of PRN medications may be significantly less than the maximum possible dose. 1

• Overlooking patient-specific factors: Age, renal/hepatic function, and prior opioid exposure can significantly affect appropriate dosing. 1

• Inadequate monitoring: Close monitoring is essential after any opioid conversion to ensure adequate pain control and avoid adverse effects. 1