Oxymorphone is typically detectable in urine for 1 to 3 days after the last dose, though the exact window depends on the formulation you took, how long you’ve been taking it, and individual factors like liver function. The drug’s elimination half-life ranges from about 7.5 to 10 hours, meaning it takes roughly two to three days for your body to clear it almost entirely.
Elimination Half-Life by Formulation
The half-life of a drug is the time it takes for half the dose to leave your bloodstream. For immediate-release oxymorphone, the elimination half-life is approximately 7.3 to 9.4 hours. The extended-release version has a slightly longer half-life of around 10 hours, because the tablet is designed to dissolve slowly and release the drug over a longer period.
It generally takes about five half-lives for a drug to be considered fully eliminated from your body. For immediate-release oxymorphone, that works out to roughly 37 to 47 hours (about 1.5 to 2 days). For extended-release oxymorphone, full elimination takes closer to 50 hours, or just over 2 days. These are averages. Some people clear the drug faster, and some slower.
Immediate-release oxymorphone reaches its peak blood concentration quickly, with a median time of about 30 minutes after taking a dose. The extended-release form peaks later, at around 1.5 to 3.5 hours.
Detection Windows by Test Type
How long oxymorphone shows up on a drug test depends on the type of sample being collected.
- Urine: 1 to 3 days after the last dose. This is the most common testing method. Standard opiate immunoassay panels often do not flag oxymorphone on their own, so labs typically need to test for it specifically using a targeted screen.
- Blood/plasma: Blood tests reflect a shorter window, generally correlating with the drug’s plasma half-life of 7.5 to 9.5 hours. Oxymorphone is usually undetectable in blood within 24 hours of the last dose, though this varies with repeated or high-dose use.
- Hair: Like most opioids, oxymorphone can be detected in hair follicle tests for up to 90 days.
For federally regulated workplace testing, such as Department of Transportation screenings, the cutoff level for both the initial and confirmatory test is 100 ng/mL. Below that concentration, the result is reported as negative.
How Your Body Processes Oxymorphone
Unlike many opioids that are broken down by the liver’s cytochrome P450 enzyme system, oxymorphone follows a different metabolic route. It is processed primarily through a reaction called glucuronidation, carried out by an enzyme known as UGT2B7. This distinction matters because it means oxymorphone has fewer drug interactions than opioids that rely on the more commonly involved liver enzymes.
The body does produce a small amount of an active byproduct called 6-hydroxy-oxymorphone, but it accounts for less than 1% of the dose excreted in urine. Most of the drug leaves the body as inactive compounds filtered through the kidneys.
Factors That Speed Up or Slow Down Clearance
Several variables influence how quickly oxymorphone leaves your system:
- Liver and kidney function: Because oxymorphone is processed in the liver and excreted by the kidneys, impairment in either organ slows elimination significantly. People with moderate liver disease can have substantially higher blood levels from the same dose.
- Age: Older adults tend to metabolize drugs more slowly due to reduced liver and kidney efficiency, which can extend detection times.
- Food intake: Taking extended-release oxymorphone with a high-fat meal increases peak blood concentration by roughly 50% compared to taking it on an empty stomach. Higher peak levels mean the drug takes longer to fall below detectable thresholds.
- Duration of use: Single doses clear faster than repeated doses. With regular use, oxymorphone accumulates in tissues and takes longer to wash out completely. Chronic users will test positive for longer than someone who took a single dose.
- Dose size: Higher doses produce higher blood concentrations, extending the time the drug remains above a test’s cutoff level.
- Body composition: People with higher body fat percentages may retain lipid-soluble drugs slightly longer, though this effect is less pronounced with oxymorphone than with some other opioids.
Why Standard Drug Screens Can Miss It
Most workplace and clinical drug panels use an immunoassay that screens broadly for opiates like morphine and codeine. Oxymorphone, along with oxycodone, typically does not trigger a positive result on these standard opiate screens. To detect oxymorphone, the testing lab needs to run a separate, targeted immunoassay or use a more advanced method like liquid chromatography with mass spectrometry. If you know you’ll be tested specifically for oxymorphone, the 1 to 3 day urine window and the 100 ng/mL cutoff are the numbers that matter most.