OxyContin is detectable in urine for roughly 1 to 1.5 days after your last dose, though the exact window varies by test type. In saliva, it can show up for about 1 to 2 days. Blood tests have the shortest window at under 24 hours, while hair tests can look back approximately 3 months.
How OxyContin Leaves Your Body
OxyContin is a controlled-release form of oxycodone designed to release the drug steadily over 12 hours. Because of this slow-release design, it has a longer absorption phase than immediate-release oxycodone. The apparent elimination half-life of OxyContin is about 4.5 hours, compared to 3.2 hours for the immediate-release version. A half-life is the time it takes your body to clear half the drug from your bloodstream.
It generally takes four to five half-lives to eliminate a drug almost entirely. For OxyContin, that works out to roughly 18 to 23 hours before oxycodone levels in your blood drop to near zero. But “near zero in your blood” and “undetectable on a drug test” are two different things. Drug tests look for trace amounts of both the drug and its breakdown products, which can linger longer than the active drug itself.
Detection Times by Test Type
Urine
Urine testing is the most common method for workplace and clinical drug screening. Oxycodone is typically detectable in urine for 1 to 1.5 days after the last dose. Federal workplace drug tests use a cutoff of 100 nanograms per milliliter for both the initial screen and the confirmation test. One important detail: standard opiate immunoassay panels often miss oxycodone entirely. It usually requires a specific test targeting oxycodone and its metabolite oxymorphone, so the type of test ordered matters.
Saliva (Oral Fluid)
Oral fluid testing is becoming more common in workplace settings. In controlled studies, oxycodone appeared in saliva within 15 to 30 minutes of taking a dose. At the federal workplace cutoff of 15 nanograms per milliliter (used for confirmation), the average detection window was about 17.5 hours, with some individuals testing positive up to 28 hours. At a more sensitive 1 nanogram per milliliter cutoff used in some clinical settings, detection extended to an average of 34 hours and as long as 52 hours in one subject.
Blood
Blood tests have the narrowest detection window. At common testing thresholds, oxycodone is detectable in blood for roughly 10 to 14 hours after a single dose. Blood testing is rarely used for routine screening because of its short window and the need for a blood draw. It’s more common in emergency rooms or forensic investigations where recent use is the question.
Hair
Hair follicle tests have the longest lookback period. A standard 1.5-inch hair sample covers approximately 3 months of potential drug exposure. Hair testing doesn’t capture single or very recent use well, since it takes about a week for drug residues to grow out of the scalp. It’s designed to identify patterns of repeated use over time.
Factors That Slow Clearance
The timelines above are averages. Several biological factors can push oxycodone’s stay in your system longer.
Liver function plays the biggest role. Your liver handles the bulk of oxycodone metabolism, with roughly 45 to 50 percent of each dose processed by one family of liver enzymes and another 10 to 19 percent handled by a second. In people with moderate to severe liver disease, blood levels of oxycodone nearly double (a 95 percent increase in overall drug exposure). That translates directly to a longer detection window.
Kidney function matters too, since the kidneys are responsible for clearing both unmodified oxycodone and its metabolites. Kidney impairment raises oxycodone and metabolite concentrations by about 50 and 20 percent, respectively.
Age changes the equation. The plasma half-life increases by about 30 percent in older adults, and overall drug exposure runs roughly 20 percent higher than in younger people at the same dose. At the other end of the spectrum, clearance rates in newborns increase gradually from birth through the first six months of life.
Sex is another factor. Oxycodone concentrations run approximately 25 percent higher in women than in men, even after adjusting for body weight differences. This means women may test positive slightly longer after an equivalent dose.
Genetics influence how efficiently your liver enzymes break down the drug. An estimated 5 to 10 percent of white individuals carry gene variants that reduce their ability to metabolize oxycodone through one of the key enzyme pathways. The prevalence varies across populations, with lower rates in Asian populations (1 percent or less) and highly variable rates in African populations. If you’re a slower metabolizer, the drug lingers longer.
Other medications can interfere as well. Drugs that inhibit the liver enzymes responsible for breaking down oxycodone will increase your exposure and extend detection times. Stopping certain medications that speed up oxycodone metabolism, such as some anti-seizure drugs, can also cause a temporary spike in oxycodone levels.
Chronic Use Extends Detection
The detection windows listed above are based largely on single-dose studies. If you’ve been taking OxyContin regularly, oxycodone accumulates in your body tissues over time. Stable plasma levels are typically reached within 24 to 36 hours of consistent dosing, and with repeated use, the drug and its metabolites build up. This means a long-term user will test positive for longer than someone who took a single pill. The urine window, for instance, can extend well beyond the standard 1.5 days depending on dose, duration of use, and individual metabolism.
OxyContin vs. Immediate-Release Oxycodone
OxyContin’s controlled-release design means it enters your bloodstream more slowly and maintains detectable levels longer than immediate-release oxycodone. The absorption pattern is biphasic: an initial release with a half-life of about 0.6 hours, followed by a prolonged release phase with a half-life of 6.9 hours. In practical terms, this means oxycodone from an OxyContin tablet is still being absorbed hours after an equivalent immediate-release dose would have peaked and started declining. The net effect is a modestly longer detection window for OxyContin compared to its immediate-release counterpart.
Withdrawal Onset as a Timing Clue
If you’re physically dependent on OxyContin, withdrawal symptoms offer a rough biological signal that the drug is leaving your system. For short-acting opioids like immediate-release oxycodone, withdrawal typically begins 8 to 24 hours after the last dose and lasts 4 to 10 days. For longer-acting formulations, onset can range from 12 to 48 hours, with symptoms lasting 10 to 20 days. OxyContin falls somewhere between these categories: it’s a controlled-release formulation of a relatively short-acting opioid, so most people begin feeling withdrawal effects within 12 to 24 hours of their last dose.