Oxymorphone

Opioids and antagonists
Opioids and antagonists
High alert
An error with this medicine can cause serious harm: double checks and protocols are used.

A potent full μ-opioid agonist for severe acute pain. Little is absorbed by mouth, food and alcohol raise its levels, and liver disease is a contraindication.

Updated Nov 1, 2026

Quick facts

Group: Opioids and antagonists
Target: μ-opioid receptor
Key effects: Nausea and vomiting · Somnolence and dizziness
Monitor: Respiratory rate · Pain score
ATC: N02AA11

No doses: the clinician sets them by the current guideline.

Mechanism of action

μ-opioid receptorOxymorphone

The figure shows morphine in the μ receptor; oxymorphone, a closely related morphinan, occupies the same site.

Target in 3D: μ-opioid receptor. PDB structure 8EF6 (RCSB PDB, public domain). View the structure at RCSB PDB

Oxymorphone is a full opioid agonist, relatively selective for the μ receptor. As a full agonist its analgesia has no ceiling; respiratory depression rises with the dose in the same way.

Activates μ-opioid receptors
Gi signalling reduces release of pain transmitters
Strong analgesia without a ceiling, and respiratory depression

Indications

Short-term acute pain severe enough to need an opioid

Adverse effects

Common

Nausea and vomiting
Somnolence and dizziness
Itching
Constipation
Headache and confusion

Contraindications

Significant respiratory depression
Acute or severe asthma without monitoring or resuscitation equipment
Known or suspected bowel obstruction, including paralytic ileus
Moderate or severe liver impairment

Key interactions

Benzodiazepines, alcohol and other CNS depressants: Additive sedation and respiratory depression, with risk of death
Alcohol: Higher oxymorphone levels and possible fatal overdose
MAO inhibitors: Potentiated opioid effects; avoided within 14 days

What is monitored

Respiratory rate, sedation level and oxygen saturation, above all at the start and after dose changes
Pain score, bowel habit and signs of misuse
Liver function before treatment

Administration and safety

Controlled medicine (Schedule II in the United States): counted, stored locked and documented
Oral tablets are swallowed whole; crushing or dissolving them for injection is dangerous
Look-alike risk with other opioids of similar name: check the name and the formulation
Taken on an empty stomach, apart from meals

Pregnancy and breastfeeding

Prolonged use in pregnancy can cause neonatal opioid withdrawal syndrome.

Nursing care

Check breathing rate and sedation before each dose and hold the drug if the patient is hard to wake
Keep naloxone available and know the local overdose protocol
Start a bowel regimen and watch for urinary retention
Teach safe storage away from children, no alcohol and no driving while drowsy

Pharmacokinetics

Absorption: Only about 10% reaches the blood by mouth; it is taken on an empty stomach
Metabolism: In the liver by reduction and glucuronidation, with little CYP role; 6-hydroxy-oxymorphone is active
Half-life: About 9 to 11 hours after a single oral dose

Test yourself

Think of the answer, then tap the question to see it.

Which liver condition contraindicates oral oxymorphone?

Moderate or severe hepatic impairment.

What does alcohol do to oxymorphone levels?

It raises them, with risk of fatal overdose.

Is oxymorphone a partial or a full μ agonist?

A full agonist, so analgesia has no ceiling.

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Connections

← Back to the class: Opioids and antagonists

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - OXYMORPHONE HYDROCHLORIDE tablet (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.