How Long Does Fentanyl Stay in Your System?

In 2020, an estimated 9,490,000 people in the United States 12 years old or older used fentanyl in the past year, according to the National Survey of Drug Use and Health (NSDUH).

Since so many people misuse opioid drugs such as fentanyl, many wonder how long it might take to get through withdrawal or pass drug screenings after use. 

How Quickly Does Fentanyl Take Effect?

man experiencing fentanyl withdrawalHow fast fentanyl is absorbed into someone’s system depends on the method of use. There are several ways to use fentanyl, such as:

  • Injecting the drug (fentanyl often appears as an adulterant in heroin).
  • Snorting crushed pills.
  • Smoking crushed pills.
  • Swallowing pills, or sucking lozenges or lollipops.
  • Applying multiple transdermal pain patches or extracting the drug from the patches.

People who inject the drug will have it coursing through their bloodstream almost immediately. Snorting is second in line to injecting, though not all of the fentanyl is absorbed this way because much of it is swallowed and enters the bloodstream later by way of the stomach and digestive tract. The drug is absorbed through the mucosal membranes inside the nose and meets the bloodstream soon after. Both snorting and injecting fentanyl generally produce a strong rush that people who misuse fentanyl often enjoy.

Smoking crushed fentanyl also causes the effects to be felt quite quickly, but it is hard to determine this without controlling for the dose being used.

Pain patches allow fentanyl to be absorbed through the skin. Transdermal absorption rates are slower to allow for a paced release of the drug over a long period of time, per the National Capitol Poison Center.

Subcutaneous absorption through lollipops occurs in the stomach and digestive tract just like swallowing pills does and typically takes the longest to start producing a high effect. From the point of administration, fentanyl spreads through the body into tissues and organ systems. How long it takes to leave the body is also dependent on the method of administration, as well as the metabolism of the individual abusing it.

Side Effects of Fentanyl Use

Withdrawal involves the physical and mental events that occur as a result of the weaning process once a dependence on opioids or other substances has formed. While withdrawal can lead to a variety of uncomfortable symptoms, the process can be effectively managed via medical detox.

The biggest risk posed by fentanyl is overdose, and this risk is highly dependent on how often the drug is used and which method of administration applies. For example, doses are far more controlled for users who just swallow the pills as they come. However, much of the fentanyl misused is manufactured illegally. Counterfeit pills containing lethal doses of fentanyl may be virtually indistinguishable from prescription pills sold at pharmacies.

How Long Does It Take for Fentanyl to Leave the Body?

The elimination half-life of fentanyl varies depending on how it is administered. Injected fentanyl leaves the body more quickly than when it is received through snorting, smoking, or pain patches.

It can take as long as 22 hours for the blood plasma to clear itself of fentanyl when it’s injected. It generally takes closer to 1.6 days for fentanyl to be eliminated from the body through other methods of administration.

Treatment for Fentanyl Addiction

group therapy for fentanyl addiction treatmentOften, withdrawal symptoms drive people to want to use again in order to make these uncomfortable symptoms go away. Our Hollywood, FL medical detox program can lessen the side effects of withdrawal and make the detox process more comfortable. Medications are often administered to ease withdrawal and cravings.

Clients need to go through detox to deal with the physical aspects of dependency, but withdrawal won’t address psychological addiction or the desire to use fentanyl as a crutch when triggers arise. Therapies used in addiction treatment and the support that patients garner from their peers and treatment professionals help patients avoid relapse.

Recovery First, one of American Addiction Centers’ rehab centers in Florida, is ready to help you recovery from fentanyl addiction and achieve long-term sobriety. Call us today at to learn more about addiction treatment near you.

Was this page helpful?
Thank you for your feedback.

American Addiction Centers (AAC) is committed to delivering original, truthful, accurate, unbiased, and medically current information. We strive to create content that is clear, concise, and easy to understand.

Read our full editorial policy

While we are unable to respond to your feedback directly, we'll use this information to improve our online help.

You aren't alone. You deserve to get help.
Recovery First is located in Hollywood, Florida, which is easily accessible from Miami or Ft. Lauderdale. Our small groups means you get more one-on-one support and make stronger connections with the community. Take the next step toward recovery: learn more about our addiction treatment programs near Florida's Atlantic coast or learn about how rehab is affordable for everyone.