How Long Does Fentanyl Stay in Your System?

How Long Does Fentanyl Stay in Your System

Fentanyl use has escalated over the last few years, leading to a drastic increase in overdoses and deaths. Fentanyl is a powerful synthetic opioid that doctors use to treat severe pain.

Although it was originally meant for prescription use, it’s now widely available on the street, and it’s deadly. Are you asking, “How long does fentanyl stay in your system?” The answer varies based on several factors, including the method of testing.

If you’re dealing with an addiction to fentanyl, you should know you’re not alone and there is help and treatment available.

Here’s a guide to how long fentanyl will remain in your system after use.

How Does Fentanyl Work?

Fentanyl is a potent opioid that’s similar to morphine. However, it’s 50 to 100 times more potent than morphine.

Fentanyl, like heroin and morphine, attaches to the opioid receptors in the brain. This area controls your emotions and regulates pain.

Fentanyl interacts with these receptors and enhances the release of dopamine. This sudden increase in dopamine is thought to enhance the euphoric high of fentanyl.

Users get an immediate rush or high, but it also leads to decreased respiration, which increases the chance of an overdose.

Fentanyl is extremely addictive and can negatively affect your life in numerous ways. Over time, the brain adapts to the presence of the drug, making the user less sensitive to its effects.

As the addiction takes hold, the user begins to lose the ability to feel joy or pleasure unless they’re using fentanyl.

Side effects of using fentanyl include:

  • Confusion
  • Drowsiness
  • Nausea
  • Vomiting
  • Dizziness
  • Constipation
  • Urinary retention
  • Constricted pupils
  • Respiratory depression

How Long Does Fentanyl Stay in Your System?

Fentanyl Testing

The detection time for fentanyl testing varies depending on several factors. These include your general health, dosage, and type of drug test.

Here’s a look at detection times for fentanyl.

Fentanyl Plus Other Substances

If you’re using fentanyl with other drugs, it can affect fentanyl’s rate of metabolism. Using fentanyl, along with cocaine, methamphetamine, heroin, or prescription drugs, is dangerous and life-threatening.

How Often You Use Fentanyl 

The length of time you’ve used fentanyl and how often you use it can affect how long it remains in your system. The longer you’ve used fentanyl, the longer it stays in your system after ingestion.

How You Use Fentanyl

The way you ingest fentanyl affects the amount of time it stays in your system. If you inject it intravenously, it’s eliminated from the body faster than by other methods. 

How Much You Use

Larger doses of fentanyl will stay in your system longer than a smaller dose. Any dose of fentanyl that’s not prescribed by your doctor is too much and could lead to an overdose, addiction, or even death.

If you’re stuck in a cycle of addiction, there is help and hope for a life free of addiction. 

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Your Liver Function

Frequent drug use damages your organs, including your liver. If your liver isn’t functioning as it should, it can slow the metabolism of fentanyl in your body.

Body Mass and Weight

The body distributes fentanyl to fatty tissue. Someone with more body fat will metabolize the drug slower than someone with less body fat.


Age does play a role in how quickly the body metabolizes fentanyl. Someone older may take longer to metabolize fentanyl.


Studies show that the enzyme CYP3A4 plays a role in metabolizing fentanyl in the body. Someone with poor enzyme function may have difficulty metabolizing and eliminating fentanyl from their system.

How Long Is Fentanyl Present in Urine?

Urine Test for Fentanyl

Fentanyl and its metabolites are present in urine two to three hours after ingestion. They can show up in a urine drug test one to three days after use.

How Long Is Fentanyl Present in the Blood?

Blood tests can screen for fentanyl but aren’t as widely used as urine tests. Blood tests can detect oral fentanyl for up to three days, IV fentanyl for up to 20 hours, and transdermal fentanyl (patch) for three to four days.

How Long Is Fentanyl Present in Saliva?

It can be challenging to detect fentanyl in saliva. This is especially true for someone using a transdermal patch or injecting fentanyl.

For this reason, saliva tests aren’t typically used to test for fentanyl.

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How Long Is Fentanyl Present in Hair?

Hair testing is a reliable method for testing fentanyl and other synthetic opioids. The downside is that it can take a few days to detect the drug in hair samples. 

After a few days, hair testing can detect fentanyl up to 90 days after use.

What Happens If You Take Too Much Fentanyl?

Fentanyl is extremely potent, and the potential for overdose is high. The chance of an overdose increases if you take fentanyl but think it’s another drug or you combine it with alcohol or other substances.

Signs of fentanyl overdose include:

  • Decreased or stopped breathing
  • Cold and clammy skin
  • Blue lips or skin
  • Stupor
  • Constricted pupils
  • Loss of consciousness
  • Seizures
  • Coma 

A fentanyl overdose can be fatal. If you suspect someone has overdosed, call for help immediately. Medical professionals can use naloxone to reduce the effects of opioids.

Getting Help for a Fentanyl Addiction

Getting Help for a Fentanyl Addiction

If you have a physical dependency on fentanyl, you’re more likely to experience intense withdrawal symptoms as you try to abstain. The severity of withdrawal symptoms depends on the length and intensity of your drug use.

If you’re ready to get help, you’ll need medical detox, addiction treatment, and substance abuse therapy to beat a fentanyl addiction. Asking for help is the first step toward going to rehab and living the life you truly deserve.

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Find the Right Treatment Center 

Fentanyl drug abuse is growing across the country, and so are overdoses and deaths. Fentanyl is an addictive and dangerous substance, and the time to quit using it is now.

If you’re questioning how long does fentanyl stays in your system, chances are you or a loved one needs help. At Purpose Healing Center, we know that everyone’s journey to recovery is unique.

We offer customized treatment plans to ensure you get the education, treatment, and tools you need to move on to a better life.

Reach out today to learn more about what Purpose Healing Center has to offer.