Subutex is a narcotic drug indicated to treat the opioids addiction (dependence) that occurs in the individuals abusing and/or misusing narcotics, such as morphine, heroin, codeine, oxycodone, and hydrocodone. Subutex is available as sublingual tablets, synthesized in 2 different dosage strengths, including 2mg and 8mg. The active ingredient Subutex tablets contain is buprenorphine, which is combined with hydrochloride. 
How does Subutex work
Subutex substitutes for the opioids the patient is addicted to, as it can bind to the same receptors in the brain, including μ (mu) and k (kappa) receptors. What makes Subutex effective is that it slowly and partially binds to the receptors, decreasing the need to other opioids. The same time, it has milder side effects, compared to methadone. 
How long does Subutex stay in your system
Subutex can appear in the plasma as early as 30 minutes to 3.5 hours after it has been administered. The half-life of buprenorphine ranges from 28 – 37 hours, which can be simply defined as the time the body takes to metabolize (clear out) 50% of Subutex. Therefore, Subutex is likely to stay in the system for around 56 – 74 hours after administration. 
How long is Subutex detectable
Subutex can’t be detected in saliva or fingernails. But, it can be detected in urine, blood, and hair for up to 4 days after administration.
Will Subutex show on a drug test?
No and Yes. That entirely depends on the techniques used in drug testing. Subutex can’t be detected through the standard drug screen panels, which are commonly used. Only specific techniques can detect Subutex. Currently, these techniques are not so common.
Do drug tests work on Subutex
As mentioned above, specific tests are required to detect Subutex; otherwise, Subutex is not likely to be detected, even if you undergo urine-or-blood-opioid testing. The reason is that Subutex’s metabolites differ from the metabolites common drug tests look.
What drug tests will show the presence of Subutex in the system
The two tests below can detect Subutex through the detection of buprenorphine, as follows:
Gas chromatography/mass spectrometry (GC/MS)
Through the gas-chromatography/mass-spectrometry test, buprenorphine can be detected in blood, urine, and hair.
That test depends on detecting norbuprenorphine in the urine. Norbuprenorphine is the metabolite resulting from the main ingredient of Subutex (buprenorphine).
How is Subutex stored in the body
After Subutex absorption, it is quickly distributed to different body parts through the bloodstream. Because of the long half-time of Subutex, it stays active in the body for a long time. Afterward, buprenorphine is metabolized by glucuroconjungation and cytochrome P450 CYP3A4, resulting in the norbuprenorphine-metabolite, which is less active. Then, an amount of norbuprenorphine metabolite is excreted through stool; while a smaller amount is excreted through urine. 
The information provided on this site is intended for your general knowledge only and is not a substitute for professional medical advice or treatment. Always consult your doctor.