What is the equivalent dose of morphine (oral) for 36 mg of IV Dilaudid (hydromorphone) in 24 hours?

Hydromorphone IV to Oral Morphine Conversion

36 mg of IV hydromorphone in 24 hours is equivalent to approximately 180-216 mg of oral morphine per day. 1, 2

Conversion Calculation

• When converting from IV hydromorphone to oral morphine, use a conversion ratio of approximately 1:5-6 1
• IV hydromorphone is approximately 5-7 times more potent than IV morphine 1, 2
• For oral to parenteral hydromorphone conversions, a ratio of approximately 5:1 is supported, with oral hydromorphone having approximately one-fifth the potency of parenteral hydromorphone 2
• The CDC Guideline for Prescribing Opioids for Chronic Pain indicates that hydromorphone has a conversion factor of 4 when calculating morphine milligram equivalents (MME) 2

Step-by-Step Conversion Process

1. Calculate total daily IV hydromorphone dose: 36 mg/24 hours 1

2. Convert IV hydromorphone to IV morphine equivalent:

   • Using a ratio of 1:5,36 mg IV hydromorphone = 180 mg IV morphine 1, 2

3. Convert IV morphine to oral morphine:

   • IV morphine to oral morphine ratio is approximately 1:3 (accounting for oral bioavailability) 3, 2
   • Therefore, 180 mg IV morphine = 540 mg oral morphine

4. Account for incomplete cross-tolerance:

   • When converting between opioids, reduce the calculated dose by 25-50% to account for incomplete cross-tolerance 3, 4
   • This would result in a starting oral morphine dose of 270-405 mg/day 3

Clinical Considerations

• The conversion ratio may vary based on the patient's current opioid tolerance level 3, 5
• Higher doses of hydromorphone (≥30 mg/day) may require a lower conversion ratio to other opioids 5
• For patients with 36 mg IV hydromorphone daily, the National Comprehensive Cancer Network recommends careful monitoring after conversion for both pain control and potential adverse effects 2

Important Caveats

• These conversion factors are approximate guides, and clinical judgment is essential when converting between opioids 2, 6
• There is significant variability in opioid conversion calculations among healthcare professionals, particularly for high-potency opioids 6
• After conversion, patients should be monitored closely for both efficacy and side effects, with dose adjustments made as needed 3, 2
• Consider dividing the total daily oral morphine dose into multiple doses (e.g., every 4 hours for immediate release or every 12 hours for extended release) 3, 1

Alternative Approach Using Methadone

• For patients on high doses of IV hydromorphone, methadone may be considered as an alternative oral opioid 4
• When converting from IV hydromorphone to oral methadone, a ratio of approximately 1:4-5 is recommended 4
• The initial methadone dose should be reduced by 50% for incomplete cross-tolerance 4
• Methadone requires careful monitoring due to its long half-life and potential for drug interactions 3, 4