What is Oxymorphone?

Oxymorphone is a potent semi-synthetic opioid used for moderate to severe pain. It is chemically related to oxycodone, but is significantly stronger.

Key points

• Brand names: Opana, Opana ER (mostly in the United States)

• Strength: About 2× stronger than oxycodone and roughly 10× stronger than morphine by milligram

• Forms:

  • IR (Immediate Release) tablets

  • ER (Extended Release) tablets

  • Injectable form exists but is uncommon outside hospitals

How it works

It is a full mu-opioid receptor agonist, producing:

• pain relief

• sedation

• euphoria (high misuse potential)

• respiratory depression

Pharmacology

• Onset: 10–30 minutes (IR)

• Peak: 30–60 minutes (IR)

• Duration: 3–6 hours for IR, up to 12 hours for ER

• Half-life: ~7–9 hours

Withdrawal

Very similar to hydromorphone or oxycodone, but often more intense:

• onset: 8–12 hours

• peak: 48–72 hours

• duration: 5–7 days

Availability in Canada

• Not commonly prescribed.

• Oxymorphone products have largely been withdrawn from the U.S. market due to high misuse and safety concerns, and are rare or unavailable in Canada.