Converting Oral Hydromorphone to IV Infusion Pump
The conversion ratio from oral hydromorphone to intravenous (IV) infusion is 2.5:1, meaning that 1 mg of IV hydromorphone is equivalent to 2.5 mg of oral hydromorphone. 1
Conversion Process
Step 1: Calculate Total Daily Oral Dose
- Determine the total 24-hour oral hydromorphone dose the patient is currently taking 1
Step 2: Apply Conversion Ratio
- Divide the total daily oral hydromorphone dose by 2.5 to obtain the equivalent IV dose 1
- For example: 20 mg oral hydromorphone daily ÷ 2.5 = 8 mg IV hydromorphone daily
Step 3: Calculate Hourly Infusion Rate
- Divide the total daily IV dose by 24 to determine the hourly infusion rate 2
- For example: 8 mg IV hydromorphone daily ÷ 24 = 0.33 mg/hour
Special Considerations
Dose Adjustments
- Consider reducing the calculated IV dose by 25-30% when converting from oral to IV route to account for individual variability and incomplete cross-tolerance 2
- Titrate the dose upward as needed based on pain control and side effects 2
Patient Monitoring
- Monitor patients closely during the first 24-48 hours after conversion for signs of over-sedation or inadequate pain control 1
- Assess pain intensity regularly using validated pain scales to guide dose adjustments 2
Breakthrough Pain Management
- Provide rescue doses for breakthrough pain at 10-15% of the total daily IV dose 2
- Breakthrough doses can be administered every 1-2 hours as needed 2
High-Dose Considerations
- For patients receiving ≥30 mg of IV hydromorphone daily, a lower conversion ratio may be required when rotating to other opioids 1
- Higher doses may require more careful monitoring for adverse effects 2
Renal Impairment
- Use hydromorphone with caution in patients with renal impairment as metabolites may accumulate 2
- Consider dose reduction and increased monitoring interval in patients with significant renal dysfunction 2
Alternative Routes
- If IV access is problematic, subcutaneous infusion can be used at the same dose as IV infusion 2
- The relative potency between IV and subcutaneous routes is approximately 1:1 2
Remember that individual patient response to opioids varies considerably, and close monitoring with dose adjustments is essential to achieve optimal pain control while minimizing adverse effects 2.