What is the equivalent daily dosage of hydromorphone (opioid analgesic) to 40mg of oxycodone (opioid analgesic) daily?

Hydromorphone Equivalent Dose for 40mg Daily Oxycodone

For a patient taking 40mg of oral oxycodone daily, the equivalent dose of oral hydromorphone is approximately 7.5 mg daily, which should be reduced by 25-50% to 3.75-5.6 mg daily (typically rounded to 4-6 mg daily in divided doses) when converting between opioids to account for incomplete cross-tolerance. 1

Calculation Method

Step 1: Convert Oxycodone to Morphine Equivalents

• Oxycodone 40 mg/day × 1.5 (conversion factor) = 60 MME (morphine milligram equivalents) per day 1, 2
• The CDC establishes a conversion factor of 1.5 for oxycodone to morphine equivalents 1, 2

Step 2: Convert Morphine Equivalents to Hydromorphone

• Using the conversion table: 60 mg oral morphine = 7.5 mg oral hydromorphone 1
• The CDC conversion factor for hydromorphone is 5.0, meaning hydromorphone is 5 times more potent than morphine 1
• Therefore: 60 MME ÷ 5.0 = 12 mg hydromorphone would be the calculated equianalgesic dose

However, there is a critical discrepancy in the guideline conversion tables that must be addressed:

Reconciling the Conversion Data

• The NCCN fentanyl conversion table indicates that 60 mg oral oxycodone = 15 mg oral hydromorphone 1
• This suggests a direct oxycodone to hydromorphone ratio of approximately 4:1 (oral to oral)
• Using this ratio: 40 mg oxycodone ÷ 4 = 10 mg oral hydromorphone as the calculated equianalgesic dose

Recommended Starting Dose

The safest approach is to start with 5-7.5 mg oral hydromorphone daily (50-75% dose reduction from calculated equianalgesic dose), divided into doses every 4-6 hours. 1

Dosing Schedule Options:

• Conservative approach: 1 mg every 4 hours (6 mg/day total) 1
• Moderate approach: 1.5 mg every 4 hours (9 mg/day total) - only if pain was poorly controlled on oxycodone 1
• Provide immediate-release hydromorphone 0.5-1 mg every 2-4 hours as needed for breakthrough pain 1

Critical Safety Considerations

Mandatory Dose Reduction When Converting

• Always reduce the calculated equianalgesic dose by 25-50% when rotating between opioids to account for incomplete cross-tolerance and individual pharmacokinetic variability 1
• If the patient's pain was well-controlled on oxycodone 40 mg/day, use a 50% reduction (start with 5 mg hydromorphone/day) 1
• If pain was poorly controlled, may use only a 25% reduction or start at full equianalgesic dose, but monitor closely 1

Important Caveats

• Conversion factors are estimates only and cannot account for individual variability in genetics and pharmacokinetics 1, 2
• Never use calculated MME doses directly when converting between opioids - the new opioid must be dosed substantially lower than the calculated dose 1, 2
• Hydromorphone has a shorter duration of action (4-6 hours) compared to extended-release oxycodone formulations 1

Special Population Warning

• Avoid hydromorphone (and morphine) in patients with renal failure due to accumulation of renally cleared metabolites that can cause neurotoxicity 1, 2

Monitoring and Titration

• Reassess pain control and side effects within 24-48 hours of conversion 3
• Titrate upward based on breakthrough medication requirements 3
• Monitor closely for signs of oversedation or respiratory depression, especially in the first 24-72 hours 1
• The peak respiratory depressant effect may occur at different times than peak analgesic effect 1