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How long does Fentanyl stay in your system?

Medically reviewed by Carmen Pope, BPharm. Last updated on Aug 28, 2024.

Official answer

by Drugs.com

Traces of fentanyl can stay in your system for a lot longer than it takes for the effects of fentanyl to wear off. Drug testing can detect fentanyl or its metabolites (breakdown products) in urine for 24 to 72 hours, in blood for 5 to 48 hours, and in hair for up to 3 months, but it cannot be consistently detected in saliva.

Fentanyl has a half-life of 7 hours and experts usually agree that it takes 4 to 5 half-lives for a drug to be cleared from your body (which calculates to 35 hours). However, the actual length of time fentanyl stays in your system depends on what dose you took and how you took it (for example, by injection, via a patch, or orally), if you have been taking it for a long time, your weight, what other medications you take, and if you have kidney or liver disease. Someone using the drug once or twice can process and remove fentanyl much faster than someone who uses high doses consistently.

What is fentanyl?

Fentanyl is a synthetic opioid that may be prescribed for difficult-to-treat pain. The prescription version may come in the form of a tablet, lozenge, or patch, but fentanyl may be used illegally to lace other substances, such as cocaine.
Note that doses are not equivalent between the different formulations (for example a 25mcg fentanyl patch DOES NOT EQUAL 25mcg of fentanyl injection). The substitution of one fentanyl product for a different type of fentanyl product (for example Subsys for Duragesic) may result in a fatal overdose. It is always safer to underestimate fentanyl requirements.

Fentanyl is a schedule II-controlled substance that is up to 100 times more potent than morphine on a weight-for-weight basis. Overdose is a serious concern with fentanyl, particularly since it is often combined with other substances including alcohol. Respiratory depressant effects can be seen from as early as 15-30 minutes after administration and persist for several hours.

Fentanyl has a high potential for abuse and may be used to covertly lace counterfeit drugs. Several deaths have been reported in people unknowingly consuming fentanyl, for example, from Xanax-laced with fentanyl.

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References
  • Fentanyl Buccal tablets Revised 05/2020 Drugs.com https://www.drugs.com/ppa/fentanyl.html
  • FentaNYL 05/2020 Drugs.com https://www.drugs.com/ppa/fentanyl.html
  • Wagener D. Updated Aug 17, 2022. American Addiction Centers. How Long Does Fentanyl Stay in Your System? https://americanaddictioncenters.org/fentanyl-treatment/how-long-in-system

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Fentanyl test strips can be found at your local health department, at a community needle-exchange program, from reliable online sources, or even vending machines in some states. Once the strip is dipped into a sample of the drug (usually dissolved in a small amount of water), the results indicate if fentanyl is present. Follow the instructions for use on your specific test strips. Continue reading

What are the symptoms of a fentanyl overdose?

A fentanyl overdose may result in signs and symptoms such as:

  • stupor (dazed or nearly unconscious)
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  • cyanosis (bluish or purplish tint to the skin, lips or fingernails due to low oxygen levels)
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How does fentanyl compare to heroin or other opiates?

Fentanyl is an extremely potent, synthetic (man-made) opioid. It is about 50 times more potent than heroin and 100 times more potent than morphine. In contrast, heroin is 2 to 3 times more powerful than morphine. Fentanyl is a legally prescribed drug for pain in the US and is classified as Schedule II controlled substance when used for legitimate purposes. Heroin is illegal in the U.S. and is classified as a Schedule I controlled substance. Continue reading

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