The short answer
For most opioids the windows are short: 6 to 24 hours in blood, 24 to 48 hours in saliva and 1 to 3 days in urine after a single dose, stretching to 2 to 4 days with daily use. Three members break that pattern — buprenorphine (blood 1 to 3 days), methadone (blood up to 5 days on daily dosing) and fentanyl, whose urine tail reaches 14 to 28 days with daily or patch use.
Opioid is a class name, not a molecule. It spans four orders of magnitude in potency, and the spread in detection windows is almost as wide. So before asking how long, it is worth asking what the test in front of you was built to find — because for most of this class, the honest answer is: something else.
How long are opioids detectable in blood, saliva and urine?
| Molecule | Blood | Saliva | Urine, one-off | Urine, daily |
|---|---|---|---|---|
| Morphine, codeine, dihydrocodeine, oxycodone, hydromorphone | 6–12 h | 24–48 h | 1–3 d | 2–4 d |
| Heroin (via 6-MAM, then morphine) | 6–12 h | 6–24 h | 1–3 d | 2–4 d |
| Tramadol | 12–24 h | 24–48 h | 1–3 d | 2–4 d |
| Tapentadol, tilidine | 6–24 h | 24–48 h | 1–3 d | 2–4 d |
| Nitazenes | 6–24 h | 6–24 h | 1–3 d | 2–4 d |
| Fentanyl — bolus | 6–24 h | 24–48 h | 1–3 d | 14–28 d |
| Fentanyl — transdermal patch | 60–120 h | 24–48 h | — | 14–28 d |
| Buprenorphine | 24–72 h | 24–48 h | 3–7 d | 7–14 d |
| Methadone | 12–48 h → 2–5 d | 24–48 h | 3–7 d | 7–14 d |
These are the windows Clearhead uses in the app. Blood and saliva are anchored per molecule across a 0.1–50 ng/mL band (nitazenes 0.1; fentanyl 0.5; buprenorphine 1; hydromorphone 5; codeine, morphine, oxycodone and heroin 10; dihydrocodeine and tilidine 20; tramadol, methadone and tapentadol 50). For urine the app carries no numeric cutoff — those windows are fixed constants tied to standard screening practice, and we publish them rather than invent a threshold. Saliva has no separate daily-use window, so the figures apply to episodic and daily use alike. Estimates, not measurements.
What a standard opiate panel actually sees
| Coverage | Molecules |
|---|---|
| Reflected | Codeine, dihydrocodeine, morphine, heroin |
| Unreliable | Oxycodone, hydromorphone |
| Not detected — needs its own assay | Fentanyl, methadone, buprenorphine, tramadol, tapentadol, tilidine, nitazenes |
The dangerous belief here is that a negative standard panel means nothing is present. It does not. The panel was built around morphine-type opioids, and most of the modern class is simply not on it. Nitazenes are missed by an opiate test and by a fentanyl test; they need targeted laboratory analysis.
The reverse trap is reading a morphine result as proof of a specific source. Codeine is a prodrug — what gets registered is the morphine your body made from it — so morphine on a report does not name what was taken. The one marker unique to heroin is 6-MAM, which is not produced from codeine, morphine or poppy seeds. Its window is very short, and once it is gone only morphine remains.
The molecules that break the class average
Fentanyl — a patch is not a dose
A fentanyl bolus clears in 6 to 24 hours, but a transdermal patch keeps blood positive for 60 to 120 hours because of a skin depot with an apparent 20-hour off half-life. Daily or patch use pushes urine to 14 to 28 days — the biggest single-versus-chronic gap in the class. A standard opiate panel does not see it.
Methadone — the one that accumulates
Methadone is the only opioid the model treats as accumulating. A single dose clears in 12 to 48 hours, but daily dosing builds a tissue reservoir that holds blood positive for 2 to 5 days and urine for 7 to 14. Its half-life far exceeds its effect, so plasma can keep rising on a fixed dose and toxicity can appear on day 2 to 5; steady state takes about five days.
Buprenorphine — long half-life, very low cutoff
A 38-hour half-life and a cutoff of just 1 ng/mL give buprenorphine a blood window of 24 to 72 hours, and urine of 3 to 7 days on a single dose, 7 to 14 days on daily use. Like methadone, it is invisible to a standard opiate panel.
What moves an opioid window
Kidney function — the largest lever
It acts through metabolites rather than through the drug itself. Renal failure raises the half-life of the active morphine metabolite M6G about ten- to sixteen-fold (Osborne/Hanna 1993; Dean 2004), which is also the mechanism behind delayed respiratory depression. The model follows that literature: morphine, codeine and heroin are affected most, tramadol, dihydrocodeine and hydromorphone far less.
CYP2D6 genotype — how much active drug you make
Codeine, tramadol and dihydrocodeine are prodrugs, and the CYP2D6 enzyme decides how much active opioid your body makes from them. CPIC records roughly 96% less morphine from codeine in a poor metaboliser and about 45% more in an ultra-rapid one (Crews 2021) — which is why codeine has proved fatal in children. That moves the concentration curve, not the published detection window.
Body fat, age and route
Body fat matters only for the lipophilic members — fentanyl, buprenorphine, methadone and nitazenes. Age slows clearance too: from about 50 the windows drift toward the top of their range. Route changes absorption and peak sharply — smoked and injected reach the highest peaks — but not the detection window. It does change risk: the app weights respiratory risk by route precisely so that injecting does not read as the mildest option.
If you take opioids on prescription
A great many people reading this page are pain patients rather than recreational users. A prescription changes the legal frame around a positive result — it does not change the pharmacology, and it does not shorten a window by an hour. It also does not change what the assay looks for: if you are prescribed tramadol, methadone or a fentanyl patch, a standard opiate panel will not reflect it either way.
And if you are here because daily use has stopped feeling optional, that is dependence behaving the way dependence behaves — not a personal failing. Changes to an opioid regimen are worth making with a prescriber or a low-threshold service rather than alone, because tolerance falls faster than habit does.
Driving: a detection window is not a verdict
Detection and impairment are different questions and they do not line up. An opioid can sit well below any cutoff while sedation, slowed reaction time and next-day grogginess are still present, and it can stay detectable long after every effect has ended. A prescription does not settle that either: driving rules turn on impairment and on national law, not on whose name is on the pharmacy label. Clearhead estimates windows; it does not issue permissions. For an example of how a numeric legal threshold works where one exists, see our THC limits by country page.
Frequently asked questions
How long do opioids stay in your system?
It depends on the molecule far more than on the class. Most opioids leave blood in 6 to 24 hours, saliva in 24 to 48 hours and urine in 1 to 3 days after a single dose. Methadone, buprenorphine and fentanyl run several times longer.
Does a standard opiate test detect fentanyl?
No. A standard opiate panel reflects codeine, dihydrocodeine, morphine and heroin. Fentanyl, methadone, buprenorphine, tramadol, tapentadol, tilidine and nitazenes are not on it at all, and oxycodone is caught only unreliably. Each of those needs its own dedicated or targeted laboratory assay.
How long is tramadol detectable?
Tramadol is detectable in blood for 12 to 24 hours, in saliva for 24 to 48 hours and in urine for 1 to 3 days after a single dose, or 2 to 4 days with daily use. The model tracks tramadol plus its O-desmethyl metabolite, half-life 6.7 hours.
How long is methadone detectable?
A single dose of methadone leaves blood in 12 to 48 hours. Daily dosing builds a tissue reservoir that keeps blood positive for 2 to 5 days and urine for 7 to 14 days. It is the only opioid Clearhead treats as accumulating; steady state takes about five days.
How long is fentanyl detectable?
A bolus clears in 6 to 24 hours; a transdermal patch keeps blood positive for 60 to 120 hours because of a skin depot with an apparent 20-hour off half-life. Daily or patch use pushes urine to 14 to 28 days.
How long is buprenorphine detectable?
Buprenorphine stays in blood for 24 to 72 hours and in saliva for 24 to 48 hours. Urine runs 3 to 7 days after a single dose and 7 to 14 days on daily use. Its half-life is 38 hours and its cutoff is a very low 1 ng/mL.
How long is heroin detectable?
Heroin itself is gone within minutes and is never proven by the parent drug. Its unique marker, 6-MAM, has a very short window; after that only morphine is left. Saliva 6 to 24 hours, blood 6 to 12 hours, urine 1 to 3 days, or 2 to 4 days daily.
Does kidney function change how long opioids are detectable?
It is the largest lever in the class, and it acts through metabolites rather than the drug. In renal failure the half-life of the active morphine metabolite M6G rises about ten- to sixteen-fold (Osborne/Hanna 1993; Dean 2004) — the same mechanism behind delayed respiratory depression.
Does a prescription change the detection window?
No. A prescription changes the legal frame around a positive result, not the pharmacology — prescribed oxycodone leaves the body on the same curve as any other oxycodone. It also does not change whether a panel sees the molecule: most prescribed opioids are invisible to a standard one.
Where these numbers come from
Every window above is the one built into the Clearhead engine, tied to a published source rather than to a round number copied between websites. Thirteen molecules are modelled separately, each with its own cutoff, half-life and assay behaviour — which is why this page is a table of molecules rather than one figure for "opioids". The wider approach is on our methodology page.
Sources referenced by the model: Osborne R / Hanna M 1993 and Dean M 2004 (morphine-6-glucuronide half-life in renal failure and delayed respiratory depression) · Crews KR et al., Clin Pharmacol Ther 2021 (CPIC guideline for CYP2D6, OPRM1 and COMT genotypes and select opioid therapy; CPIC 2012 for codeine) · Algera MH et al., 2021 (opioid tolerance and respiratory effect) · SAMHSA (opiate immunoassay and confirmation cutoffs); HHS / CDC 2022 (morphine milligram equivalent conversion factors) · StatPearls monographs for methadone, fentanyl and buprenorphine; EMA Durogesic referral (transdermal fentanyl kinetics) · Perekopskiy D et al., ACS Chem Neurosci 2019 (6-monoacetylmorphine, not morphine, drives the rapid effects of intravenous heroin), plus the nitazene pharmacology literature. Reviewed 2 September 2026.