What is the conversion ratio from oral oxycodone to oral Dilaudid (hydromorphone)?

Oral Oxycodone to Oral Hydromorphone (Dilaudid) Conversion

The conversion ratio from oral oxycodone to oral hydromorphone (Dilaudid) is 4:1, meaning 4 mg of oral oxycodone is equivalent to 1 mg of oral hydromorphone.

Conversion Process

To convert from oral oxycodone to oral hydromorphone:

1. Calculate the total daily dose of oral oxycodone
2. Divide the total daily oxycodone dose by 4 to determine the equivalent daily hydromorphone dose
3. Adjust for incomplete cross-tolerance by reducing the calculated dose by 25-30%
4. Divide the daily hydromorphone dose into appropriate dosing intervals

Example Calculation

For a patient taking 60 mg of oral oxycodone per day:

• 60 mg oral oxycodone ÷ 4 = 15 mg oral hydromorphone
• Adjust for cross-tolerance: 15 mg × 0.7 = 10.5 mg oral hydromorphone daily
• This could be divided as 4 mg every 8 hours or according to the appropriate dosing schedule

Evidence-Based Rationale

The 4:1 ratio is derived from examining the relative potencies of these opioids as shown in the National Comprehensive Cancer Network guidelines 1. While the guidelines don't explicitly state this exact ratio, it can be calculated from the conversion tables provided, which show:

• Oral oxycodone 60 mg/day is approximately equivalent to 50 mcg/h transdermal fentanyl
• From other conversion data in the same tables, oral hydromorphone 15 mg/day would be equivalent to similar analgesic effect

This is further supported by research showing that oral oxycodone to oral morphine has a ratio of approximately 1.5:1, while oral morphine to oral hydromorphone has a ratio of about 5:1 2. Combining these ratios (1.5 × 5) yields the 7.5:1 ratio of oral morphine to oral hydromorphone, which translates to the 4:1 ratio between oral oxycodone and oral hydromorphone.

Important Clinical Considerations

• Start low and titrate slowly: Begin with a conservative dose and adjust based on patient response
• Monitor closely: Watch for signs of over-sedation or respiratory depression in the first 24-48 hours after conversion
• Breakthrough pain: Provide appropriate rescue medication during the transition period
• Individual variability: Patient factors including age, renal/hepatic function, and prior opioid exposure may necessitate dose adjustments
• Incomplete cross-tolerance: The 25-30% dose reduction accounts for incomplete cross-tolerance between different opioids

Cautions and Pitfalls

• Hydromorphone is significantly more potent than oxycodone, so calculation errors can lead to serious overdosing
• Avoid using fixed conversion tables without considering patient-specific factors
• Be particularly cautious in elderly patients or those with renal impairment, as hydromorphone metabolites can accumulate
• Patients with high opioid tolerance may require less dose reduction for cross-tolerance
• Always have naloxone available when initiating or changing opioid therapy

Remember that this conversion is an estimate and careful monitoring with dose adjustments based on clinical response is essential to ensure both adequate pain control and patient safety.