OxyContin (oxycodone in a controlled-release form) takes roughly 4.5 hours to reduce to half its concentration in your blood. That means the drug itself is largely cleared within about 22 hours after your last dose. But its metabolites, the breakdown products your body creates as it processes the drug, linger much longer and are what drug tests actually look for. Depending on the type of test, oxycodone can be detected anywhere from a few days to 90 days after use.
How Your Body Breaks Down OxyContin
OxyContin releases oxycodone slowly over several hours, which is why it has a longer half-life (4.5 hours) than immediate-release oxycodone (3.2 hours), according to FDA labeling data. A half-life is how long it takes for half the drug to leave your bloodstream. After roughly five half-lives, a drug is considered effectively eliminated. For OxyContin, that works out to about 22 to 24 hours.
Your liver does most of the work. One set of enzymes converts oxycodone into an inactive byproduct called noroxycodone. A second set produces oxymorphone, which is actually an active pain-relieving compound on its own. Both of these metabolites are eventually broken down further and filtered out through the kidneys. This is important because drug tests screen for oxycodone and oxymorphone together, so both the parent drug and its active metabolite can trigger a positive result.
Detection Windows by Test Type
The type of sample collected determines how far back a test can look.
- Urine: Approximately 3 days after the last dose. This is the most common test for workplace and clinical screening. Federal workplace testing uses a cutoff of 100 ng/mL for both oxycodone and oxymorphone.
- Oral fluid (saliva): Typically 1 to 3 days. Federal guidelines set the screening cutoff at 30 ng/mL and the confirmation cutoff at 15 ng/mL.
- Blood: Roughly 24 hours, since oxycodone clears the bloodstream fastest. Blood tests are less common for routine screening.
- Hair: Up to 90 days. Head hair grows about half an inch per month, so a standard 1.5-inch sample covers the previous three months. Labcorp and similar testing labs specifically list oxycodone as a detectable drug in hair panels.
These windows are averages. Mayo Clinic Laboratories notes that actual detection time depends on dose, frequency of use, and individual metabolism.
What Makes Oxycodone Stay Longer in Some People
Several factors can slow your body’s ability to clear the drug, pushing detection times toward the longer end of the range or beyond it.
Kidney function plays a major role. Research published in the Journal of Pain and Symptom Management found that oxycodone’s half-life is lengthened in people with impaired kidney function, and the excretion of its metabolites is “severely impaired.” Since the kidneys are responsible for filtering those metabolites out of the body, reduced kidney performance means they circulate longer.
Age matters because both liver and kidney function decline over time. Liver blood flow drops by about 40% over a lifetime, and kidney filtration decreases by roughly 0.75 mL per minute for each year after age 40. Both of these changes slow how quickly oxycodone is processed and eliminated. Older adults should expect the drug to remain detectable longer than younger adults taking the same dose.
Body composition has a less straightforward effect. Oxycodone is moderately fat-soluble, so people with higher body fat may retain the drug slightly longer. However, obesity also tends to increase kidney blood flow, which could offset some of that retention. The net effect varies from person to person.
Chronic use vs. a single dose also changes the picture. When you take OxyContin repeatedly, the drug accumulates to a steady-state level in your tissues. A person who has been taking it daily for weeks will have more oxycodone and metabolites stored in their body than someone who took a single pill, meaning it takes longer to clear completely. Heavy, long-term users may test positive in urine beyond the typical 3-day window.
Why Standard Opioid Panels Sometimes Miss It
Older drug tests designed to detect “opiates” (morphine, codeine, heroin) do not reliably pick up oxycodone. Oxycodone is a semi-synthetic opioid with a different chemical structure, so it requires a test specifically designed to look for it. Modern federal workplace drug panels now include a dedicated oxycodone/oxymorphone category with its own cutoff levels, separate from the codeine/morphine category. If you’re being tested for oxycodone specifically, the lab will use a targeted assay. If you’re taking it with a valid prescription, informing the testing authority beforehand can prevent a positive result from being flagged as illicit use.
Withdrawal Symptoms and Clearance
As oxycodone leaves your system, withdrawal symptoms can surface. These typically begin 12 to 48 hours after the last dose of OxyContin. Early signs include anxiety, muscle aches, sweating, and insomnia. Later symptoms, appearing around day two or three, often involve nausea, cramping, and diarrhea. The onset timing aligns closely with the drug’s half-life: once blood levels drop low enough, your nervous system reacts to the absence of the opioid it had adapted to.
For people who have been taking OxyContin long-term, withdrawal is more intense and may last a week or more. The acute physical symptoms generally peak between 48 and 72 hours, then gradually improve, though fatigue and mood disturbances can linger for weeks.