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Oxymorphone vs Hydromorphone - How do they compare?

Medically reviewed by Sally Chao, MD. Last updated on Dec 21, 2021.

Official answer


Oxymorphone and hydromorphone are slightly different at the chemical level, but they are both classified as opioid agonists. These medications both have morphine-like activity and are used for the treatment of moderate to severe pain.

  • Generic oxymorphone is available as an immediate-release and extended-release tablet. Oxymorphone was originally available as the brand names Opana and Opana ER (extended release). These were taken off the market in 2017 due to concerns with abuse. Generics are currently available.
  • Hydromorphone comes as an immediate-release and extended-release tablet, oral solution and injection. The brand name is Dilaudid.

In a very small 2021 study in Psychopharmacology, oxymorphone appeared to have a higher potency than hydromorphone and showed more drug liking and respiratory depression. This means less oxymorphone was needed to produce the same effect. However, with all opioids, there is variability in how one responds to drug potency.

Oxymorphone should be taken on an empty stomach. This means taking it one hour before eating or 2 hours after eating.
Hydromorphone can be taken without regard to meals.

Both medications are controlled substances, and they both can cause addiction. The side effects of each are similar and include:

  • Drowsiness
  • Dizziness
  • Constipation
  • Nausea and vomiting
  • Itching
  • Headache
  • Sweating
  • Dry mouth
  • Constipation
  • Insomnia
  • Decreased appetite
  • Dysphoria (feeling very bad)
  • Euphoria (feeling very good)

Respiratory depression is a severe side effect that can occur with both oxymorphone and hydromorphone. Signs of respiratory depression include reduced breathing and taking deep breaths separated by long pauses. Naloxone (an opioid antagonist) can reverse the effects of oxymorphone and hydromorphone in the event of an overdose.

Both medications must be tapered slowly when it is time to discontinue them. Stopping abruptly can result in withdrawal symptoms. Withdrawal symptoms include:

  • Watery eyes
  • Runny nose
  • Sweating and chills
  • Body aches and yawning
  • Dilated pupils
  • Feeling restless

Alcohol should be avoided during treatment with oxymorphone and hydromorphone.

  1. U.S. Food and Drug Administration (FDA). Oxymorphone (marketed as Opana ER) Information. February 6, 2018. Available at: [Accessed December 13, 2021].
  2. U.S. Food and Drug Administration (FDA). Dilaudid (hydromorphone hydrochloride) oral solution, Dilaudid (hydromorphone hydrochloride) tablets, for oral use. March 2021. Available at,019892s037lbl.pdf. [Accessed December 13, 2021].
  3. U.S. Food and Drug Administration (FDA). Opana ER (oxymorphone hydrochloride) extended-release tablets, for oral use. July 2012. Available at: [Accessed December 13, 2021].
  4. Babalonis S, Comer SD, Jones JD, et al. Relative potency of intravenous oxymorphone compared to other µ opioid agonists in humans - pilot study outcomes. Psychopharmacology (Berl). 2021;238(9):2503-2514.
  5. Narcan. Narcan (naloxone hydrochloride) nasal spray. August 2020. Available at: [Accessed December 13, 2021].

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