What is the potency of hydromorphone (Dilaudid) 0.5 milligrams compared to other opioids?

From the Guidelines

Hydromorphone 0.5 mg is approximately equivalent to 2.5 MME (morphine milligram equivalent) and is considered a relatively low dose compared to other opioids. When comparing opioid potencies, hydromorphone is generally considered about 5 times stronger than morphine on a milligram-per-milligram basis, as indicated by the conversion factor of 5.0 in the CDC clinical practice guideline for prescribing opioids for pain - United States, 2022 1. This means that 0.5 mg of hydromorphone is equivalent to 2.5 mg of morphine (0.5 mg x 5.0 conversion factor).

Some key points to consider when evaluating the potency of hydromorphone 0.5 mg include:

• The conversion factors for other opioids, such as oxycodone (1.5), hydrocodone (1.0), and codeine (0.15), can be used to estimate equivalent doses 1
• The potency of hydromorphone relates to its high affinity for mu-opioid receptors and its ability to cross the blood-brain barrier efficiently, which contributes to its stronger analgesic effects compared to morphine at equivalent doses
• Even at this low dose, patients should be monitored for side effects including respiratory depression, sedation, and constipation
• The CDC guideline recommends using particular caution when converting opioids, as the new opioid is typically dosed at a substantially lower dose than the calculated MME dose to avoid overdose due to incomplete cross-tolerance and individual variability in opioid pharmacokinetics 1

In terms of equivalent doses, hydromorphone 0.5 mg is approximately equivalent to:

• 2.5 mg of morphine (0.5 mg x 5.0 conversion factor)
• 1.67 mg of oxycodone (2.5 MME / 1.5 conversion factor)
• 2.5 mg of hydrocodone (2.5 MME / 1.0 conversion factor)
• 16.67 mg of codeine (2.5 MME / 0.15 conversion factor)

Overall, hydromorphone 0.5 mg is a relatively low dose that should be used with caution, particularly in opioid-naïve patients, elderly individuals, or those with respiratory concerns.

From the FDA Drug Label

There is inter-patient variability in the potency of opioid drugs and opioid formulations

The relative bioavailability of hydromorphone hydrochloride tablets compared to extended-release hydromorphone hydrochloride is unknown

The FDA drug label does not answer the question.

From the Research

Comparison of Hydromorphone to Other Opiates

• Hydromorphone is a potent opioid analgesic, commonly used for acute pain management 2.
• The potency of hydromorphone compared to other opiates can be measured by its equianalgesic ratios, which are not well established 3.
• Hydromorphone is approximately 5 times as potent as morphine when given orally, and 8.5 times as potent as morphine when given intravenously 4.
• A study comparing hydromorphone to oxycodone, morphine, and fentanyl found no clear evidence of a difference in pain intensity or adverse events, but the evidence is very uncertain 5.

Equianalgesic Dosing

• Initial dose recommendations for hydromorphone range from 0.1 to 2 mg for opioid-naïve patients 6.
• The dose substitution policy for hydromorphone aims to minimize the incidence of opioid toxicity while maintaining adequate pain management 6.
• A dose of 0.5 mg of hydromorphone is relatively low, but its potency compared to other opiates can vary depending on the individual and the route of administration 4.

Clinical Applications

• Hydromorphone is used for moderate to severe pain, and can be administered by injection, infusion, orally, or rectally 4.
• The side effects of hydromorphone are similar to those of morphine, with the exception of pruritus, sedation, and nausea and vomiting, which may occur less frequently with hydromorphone 4.
• Hydromorphone is commonly used in the hospital setting for acute pain management, and its use has been increasing in recent years 2.