Opioid Conversion Guidelines

Conversion Factors

The Centers for Disease Control and Prevention (CDC) establishes a conversion factor of 4 for hydromorphone, meaning hydromorphone is 4 times more potent than morphine 1
Using this conversion factor, 0.5 mg hydromorphone is equivalent to 2 mg morphine equivalents 1

The CDC guidelines confirm that the 4:1 potency ratio is the standard for calculating morphine milligram equivalents (MME) 1
When switching between hydromorphone and morphine for equivalent analgesic effect, a direct IV conversion of 0.5 mg IV hydromorphone to 2 mg IV morphine can be applied 1
To account for incomplete cross-tolerance when rotating between opioids, reduce the calculated equianalgesic dose by 25-50% 2
Close monitoring is required for oversedation or inadequate analgesia during the first 24-72 hours after conversion 2