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Oxymorphone: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on March 1, 2023.

1. How it works

  • Oxymorphone is a semi-synthetic opioid derived from thebaine, a constituent of the opium poppy, that may be used to relieve severe pain.
  • Oxymorphone is a full opioid agonist and is relatively selective for the mu-opioid receptor, although it may bind to other receptors at high dosages. Because it is a full agonist, there is no ceiling effect for pain relief. Oxymorphone has morphine-like properties and is used for the relief of severe pain that is unresponsive to less potent pain-relieving medicines.
  • Oxymorphone belongs to the class of medicines known as opioid analgesics. It may also be called a narcotic analgesic.

2. Upsides

  • Relieves severe acute and chronic pain not controlled by other pain-relieving medicines.
  • Available as a tablet, injectable solution, and rectal suppository.
  • Generic oxymorphone tablets are available.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Dizziness, headache, drowsiness, constipation, fever, nausea, vomiting, and itchy skin are the most commonly reported side effects. Insomnia, diarrhea, dry mouth, abdominal pain, decreased appetite, blurred vision, confusion, fast heart rate, low blood pressure, and increased sweating may also occur.
  • May cause shortness of breath and there is a risk of life-threatening respiratory depression (severe difficulty with breathing). More likely to occur in people who are taking extended-release tablets and also in the elderly, debilitated, or those with pre-existing breathing problems, even at moderate therapeutic dosages.
  • Oxymorphone is a schedule II controlled substance and is up to 10 times more potent than morphine on a weight-for-weight basis. Note that different sources cite different equivalent dosages; in reality, there is a wide inter-individual variation between effective opioid dosages. For this reason, it is better to underestimate oxymorphone requirements and provide rescue medication (in the form of immediate-release opioids) than to overestimate oxymorphone requirements which could lead to a fatal overdose.
  • May be sought after by drug abusers or people with addiction disorders.
  • May also cause drowsiness and affect a person's ability to drive or operate machinery. Avoid alcohol at all times (alcohol can increase blood levels of the drug leading to fatal over-dosage).
  • The risk of addiction, abuse, and misuse is high with oxymorphone tablets which can lead to overdosage and death.
  • May cause a discontinuation syndrome if abruptly stopped or interrupted (symptoms include restlessness, runny nose and eyes, muscle pain, perspiration, irritability, vivid dreams, and insomnia).
  • Because of the risk of addiction and dependence, extended-release tablets should only be used for severe, chronic pain that requires around-the-clock, long-term opioid treatment and for which other treatments have been ineffective.
  • The FDA requires a REMS (Risk Evaluation and Mitigation Strategy) for oxymorphone which means the drug company that supplies these products must make REMS-compliant education programs available to healthcare providers. Patients and their caregivers must be counseled with every prescription on safe use, serious risks, storage, and disposal of oxymorphone.
  • May not be suitable for people with respiratory disease (including asthma), moderate-to-severe liver disease, impaired consciousness, or certain gastrointestinal problems.
  • May interact significantly with other medications that cause respiratory depression, sedation, or that release serotonin.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

  • Oxymorphone is significantly stronger than morphine and may be used to relieve severe pain that is unresponsive to other opioid pain-relieving medicines. Doctors may be reluctant to prescribe oxymorphone because it has a high potential for addiction and dependence.

5. Tips

  • Swallow tablets on an empty stomach with a large glass of water at least one hour before or two hours after food.
  • Swallow oxymorphone extended-release tablets whole; never crush, chew, or attempt to dissolve, as this could lead to a potentially fatal dose of oxymorphone.
  • Never use oxymorphone extended-release tablets on an "as needed" basis.
  • Oxymorphone is a very potent medication that can cause addiction. Only take as prescribed by your doctor; never increase the dosage without his or her advice. Avoid taking oxymorphone during pregnancy and when breastfeeding. Taper off the dosage under medical supervision after extended administration because withdrawal symptoms may result.
  • Avoid alcohol while taking oxymorphone because it may increase the risk of sedation and potentially fatal side effects.
  • Initial dosages should be low especially in the elderly or with certain preexisting conditions (such as liver or kidney disease).
  • Should not be used by people with alcohol dependence or previous drug dependence. Monitor regularly for the development of dependence and addiction and do not misuse or overuse.
  • Report any breathing difficulties to your doctor immediately.
  • Laxatives may be needed to treat constipation and antiemetics may be used to relieve nausea
  • Oxymorphone is available as both immediate and extended-release tablets. Ensure you have been dispensed the correct formulation before taking it. Oxymorphone injection is also available; this is ten times more potent than oxymorphone tablets.
  • May impair reaction times and affect your ability to drive or operate machinery.
  • May lower blood pressure on standing; take your time when going from lying down to a standing up position.
  • The need for continued treatment with oxymorphone should be assessed at regular intervals.
  • Keep well out of reach of children and pets. Even one accidental dose can be fatal.

6. Response and effectiveness

  • After oral administration of immediate-release tablets, peak plasma concentrations of oxymorphone are usually reached within half to one hour. Immediate-release tablets may be taken every four to six hours. Extended-release forms are designed to last for 12 hours in the body.

7. Interactions

Medicines that interact with oxymorphone may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with oxymorphone. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with oxymorphone include:

  • antidepressants, such as tricyclic antidepressants (eg, amitriptyline), monoamine oxidase inhibitors (eg, isocarboxazid, phenelzine, and tranylcypromine), or SSRIs (eg, fluoxetine, sertraline)
  • anticonvulsants, such as carbamazepine, phenytoin, phenobarbital, or primidone
  • antipsychotics (such as butyrophenones, phenothiazines, or thioxanthenes) and atypical antipsychotics (eg, olanzapine, quetiapine, ziprasidone)
  • any medication that may cause drowsiness, such as amphetamines, benzodiazepines (eg, diazepam, lorazepam), first-generation antihistamines (such as doxylamine or promethazine), metoclopramide, or opioids (such as codeine, morphine)
  • buprenorphine
  • cimetidine
  • ipratropium
  • isocarboxazid
  • muscle relaxants, such as cyclobenzaprine
  • pentazocine
  • selegiline.

Avoid drinking alcohol or taking illegal or recreational drugs while taking oxymorphone.

Note that this list is not all-inclusive and includes only common medications that may interact with oxymorphone. You should refer to the prescribing information for oxymorphone for a complete list of interactions.


Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use oxymorphone only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2023 Revision date: March 1, 2023.