What is the equivalent dose of Dilaudid (hydromorphone) for a patient receiving 30mg of morphine every 4 hours via Patient-Controlled Analgesia (PCA)?

Morphine to Hydromorphone Conversion for PCA

When converting from 30mg morphine q4h to hydromorphone PCA, the equivalent dose would be approximately 6mg hydromorphone q4h, based on a 5:1 morphine to hydromorphone conversion ratio. 1

Conversion Ratios and Calculations

The conversion from morphine to hydromorphone requires careful consideration of the following factors:

• The standard conversion ratio of morphine to hydromorphone is approximately 5:1 1
• Some evidence suggests ratios ranging from 5:1 to 8:1 2
• For conservative dosing, especially when initiating therapy, using the 5:1 ratio is appropriate

Step-by-Step Conversion Process:

1. Calculate total daily morphine dose:
   • 30mg morphine q4h = 180mg morphine per day
2. Convert to hydromorphone using 5:1 ratio:
   • 180mg morphine ÷ 5 = 36mg hydromorphone per day
3. Divide by 6 for q4h dosing:
   • 36mg ÷ 6 = 6mg hydromorphone q4h

PCA Programming Considerations

When programming the PCA device, consider:

• Demand dose: Start with approximately 1mg hydromorphone (equivalent to 5mg morphine)
• Lockout interval: Typically 6-10 minutes
• Continuous/basal rate: If needed, approximately 0.5-1mg/hour
• 4-hour limit: Set to approximately 24mg (6mg q4h equivalent)

Important Safety Considerations

• The FDA label emphasizes using the lowest effective dosage for the shortest duration 3
• When converting between opioids, a conservative approach is advised due to incomplete cross-tolerance 3
• Consider reducing the calculated dose by 25-50% initially to account for incomplete cross-tolerance 3
• Titrate based on patient response and adjust as needed 3

Special Patient Populations

• Hepatic impairment: Start with 25-50% of the calculated dose 3
• Renal impairment: Start with 25-50% of the calculated dose 3
• Elderly patients: Consider lower starting doses and careful titration 4

Monitoring Requirements

• Monitor respiratory rate, level of sedation, pain intensity, and adverse effects 4
• Have naloxone readily available to reverse potential respiratory depression 4
• Consider prophylactic antiemetics to prevent nausea 4

Common Pitfalls to Avoid

1. Overestimation of dose: It's safer to underestimate the initial hydromorphone dose and titrate up
2. Inadequate monitoring: Respiratory depression can occur at any time during therapy, especially after dose increases
3. Failure to adjust for patient factors: Age, renal/hepatic function, and prior opioid exposure significantly impact dosing requirements
4. Not accounting for incomplete cross-tolerance: Always reduce the calculated dose when switching between opioids

Remember that individual patient response may vary, and careful titration based on pain control and side effects is essential for optimal pain management.