Hydromorphone Dose Limit
Hydromorphone has no upper dose limit—the maximum dose depends on individual tolerance and tachyphylaxis, not an arbitrary ceiling. 1
Key Dosing Parameters
Starting Doses (Opioid-Naïve Patients)
- Oral hydromorphone: Start with 2-4 mg every 4-6 hours 2
- Oral hydromorphone (alternative guideline): 8 mg starting dose 1
- IV hydromorphone: 5-10 mg equivalent to parenteral morphine (using 3:1 morphine oral:parenteral ratio) 1
Maximum Daily Dose
- No upper limit exists for hydromorphone when used appropriately 1
- The maximal dose is determined by tachyphylaxis (tolerance development), not a fixed ceiling 1
- Titrate to effect while monitoring for adverse events 2
Potency and Conversion Ratios
Relative to Morphine
- Oral hydromorphone is 7.5 times more potent than oral morphine 1
- When converting from IV morphine to IV hydromorphone, use approximately a 5:1 ratio (10 mg IV morphine = 2 mg IV hydromorphone) 3
- Hydromorphone is approximately 5-7 times more potent than morphine overall 3
Conservative Conversion Approach
- Always underestimate rather than overestimate when converting from other opioids 2
- Start with half the calculated equianalgesic dose to account for incomplete cross-tolerance 2
- Inter-patient variability in opioid potency necessitates cautious initial dosing 2
Breakthrough Dosing Guidelines
Calculating Breakthrough Doses
- Breakthrough doses should be 10-20% of the total 24-hour opioid dose 3
- For continuous infusions, give a bolus equal to or double the hourly infusion rate for breakthrough pain 3
- If two bolus doses are required within one hour, double the infusion rate 3
Frequency and Monitoring
- IV bolus doses should be available every 15 minutes for adequate pain control 3
- Assess efficacy and side effects every 60 minutes for oral hydromorphone 3
- If more than 3 breakthrough doses per day are needed, increase the scheduled dose 3
Special Population Adjustments
Hepatic Impairment
- Start with one-fourth to one-half the usual dose depending on impairment severity 2
Renal Impairment
- Start with one-fourth to one-half the usual dose depending on impairment severity 2
- All opioids should be used with caution in renal impairment 1
Safety Considerations
Respiratory Monitoring
- Monitor closely for respiratory depression within the first 24-72 hours of initiation or dose increases 2
- In one study, 2 mg IV hydromorphone caused oxygen desaturation below 95% in approximately one-third of patients, though no clinical hypoxemia occurred 4
- This suggests 2 mg IV may be excessive as a routine initial dose in opioid-naïve patients 4
Titration Strategy
- Adjust doses by 25-50% every 2-4 days when discontinuing to prevent withdrawal 2
- For chronic pain, administer around-the-clock with supplemental doses of 5-15% of total daily usage every 2 hours as needed 2
- Most patients (70%) can be stabilized with ≤2 titration steps 5
Common Pitfalls to Avoid
- Do not use mixed agonist-antagonist opioids (like buprenorphine in partial agonist mode) with hydromorphone, as this can precipitate withdrawal 3
- Do not assume equal bioavailability when converting between immediate-release and extended-release formulations—close monitoring is essential 2
- Do not order IV boluses every hour—they should be available every 15 minutes for adequate acute pain control 3