What is the equivalent dose of morphine for 20mg of Dilaudid (hydromorphone) in a patient with no known opioid tolerance and normal renal function?

Hydromorphone to Morphine Conversion

20 mg of Dilaudid (hydromorphone) is equivalent to approximately 80-100 mg of morphine, using the standard conversion factor of 4:1 to 5:1 (morphine to hydromorphone). 1

Standard Conversion Factor

The CDC and other major guidelines establish that hydromorphone has a conversion factor of 4, meaning 1 mg of hydromorphone equals approximately 4 mg of morphine milligram equivalents (MME). 1

• Using this conversion: 20 mg hydromorphone × 4 = 80 mg morphine equivalent 1
• Some clinical practice guidelines suggest a ratio closer to 5:1, which would yield 100 mg morphine equivalent 1

Route-Specific Considerations

The conversion ratio applies regardless of route (oral, IV, or subcutaneous) when comparing the same routes. 1

• For IV to IV conversion: The 4:1 ratio is directly applicable 1
• For oral to oral conversion: The same 4:1 to 5:1 ratio applies 1

Critical Dosing Precautions When Converting

When actually converting a patient from hydromorphone to morphine, you must reduce the calculated equivalent dose by 25-50% to account for incomplete cross-tolerance between opioids. 1

• If converting 20 mg hydromorphone (= 80-100 mg morphine equivalent), start with 40-60 mg morphine rather than the full calculated dose 1
• This dose reduction is essential to prevent overdose due to individual variability in opioid pharmacokinetics 1

Direction-Dependent Potency (Important Nuance)

Research evidence suggests that the conversion ratio may differ depending on which direction you're rotating. 2

• When rotating FROM morphine TO hydromorphone: use a 5:1 ratio 2
• When rotating FROM hydromorphone TO morphine: use a 3.7:1 ratio 2
• This means 20 mg hydromorphone would equal approximately 74 mg morphine when rotating from hydromorphone to morphine 2

Common Pitfalls to Avoid

Do not use calculated MME doses directly for opioid conversion without dose reduction—this is the most dangerous error and can lead to fatal overdose. 1

• Equianalgesic conversions are estimates only and cannot account for individual variability in genetics and pharmacokinetics 1
• Always start lower than the calculated equivalent dose when switching opioids 1
• Monitor closely for signs of inadequate analgesia or opioid toxicity after conversion 1

Special Population Considerations

In patients with renal impairment, avoid morphine entirely and use fentanyl or buprenorphine instead, as morphine's active metabolites accumulate dangerously in kidney disease. 3, 4, 5

• Morphine should never be used in dialysis patients or those with severe renal impairment (GFR <30 mL/min) 4, 5
• Hydromorphone also accumulates active metabolites in renal failure, though less severely than morphine 3