Hydromorphone Conversion Guidelines

Introduction to Hydromorphone Conversion

The National Comprehensive Cancer Network recommends using a 5:1 ratio for IV morphine to IV hydromorphone and reducing the calculated dose by 25-50% to account for incomplete cross-tolerance if pain was previously well-controlled 1

Determine the total amount of current opioid taken in a 24-hour period that effectively controls pain, and for patients on multiple opioids, convert all to morphine equivalents first before converting to hydromorphone 1
Use a 5:1 ratio for IV to IV conversions: 10 mg IV morphine = 2 mg IV hydromorphone, which is approximately 5-7 times more potent than morphine 1, 2
If pain was effectively controlled on the previous opioid, reduce the calculated hydromorphone dose by 25-50% to account for incomplete cross-tolerance 1, 2

Provide breakthrough doses of 10-20% of the total 24-hour dose for transient pain exacerbations 2
Administer bolus doses every 15 minutes as required for adequate pain control in acute settings, and for continuous infusions with breakthrough pain, give a bolus equal to or double the hourly infusion rate 2
If two bolus doses are required within one hour, consider doubling the infusion rate 2

The American College of Clinical Pharmacology suggests that hydromorphone is safer than morphine in renal failure, but active metabolites can still accumulate, and exposure increases 2-fold in moderate and 3-fold in severe renal impairment 2
For patients with hepatic impairment, start with one-fourth to one-half the usual dose, as exposure increases 4-fold in moderate hepatic impairment, and reduce the dose rather than extending intervals 2

If more than 3-4 breakthrough doses per day are required, increase the scheduled baseline dose by 25-50% rather than shortening the dosing interval, and when pain returns before the next scheduled dose, increase the dose rather than the frequency 2
Re-evaluate within 24 hours after dose adjustment, as steady state is reached within this timeframe, and assess efficacy and side effects every 60 minutes for oral hydromorphone after breakthrough doses 2

Do not use mixed agonist-antagonist opioids in combination with hydromorphone, as this could precipitate withdrawal, and always institute prophylactic bowel regimen with stimulant laxatives, as constipation is universal with opioid therapy 2
Monitor for myoclonus, especially with chronic use, renal failure, or dehydration, and consider the quicker onset of action of hydromorphone, which supports more frequent dosing intervals for optimal acute pain control 2