Fentanyl In Your System: How Long Does It Stay?

Fentanyl is a synthetic opioid that can be extremely deadly if misused. More people die of fentanyl and synthetic opioids than any other illegal drug due. Learn how long fentanyl in your system stays.

how long does fentanyl stay in your system iris healing

Article Contents

What is Fentanyl?

Having fentanyl in your system can be an easy way to fail a drug test. Fentanyl is an extremely dangerous synthetic, and today, more people die of fentanyl and synthetic opioid overdose than any other type of substance.

Fentanyl is significantly potent and dangerous. According to the National Institute on Drug Abuse, it is fifty to one hundred times more potent than regular morphine.1 Synthetic drugs like fentanyl are the leading cause of overdose deaths within the United States.1

How Does it Work?

Fentanyl works just like other opioids. It connects to the body’s opioid receptors to mitigate pain and reduce painful emotions, which can give people a lot of immediate pain relief and a sense of euphoria.1

Drug Class

Fentanyl is a part of the opiate narcotic class. It is categorized as an opiate because it changes how the central nervous system responds to pain.2

Brand Names

There are several brand names for fentanyl. Normally, it is sold under Abstral, Actiq, Fentora, Onsollis, and Sublimaze.3

Street Names

Sadly, fentanyl usage has increased drastically during the opioid epidemic. Several street names are used when referring to it. They are as follows:4

  • Apace
  • China White
  • Dance Fever
  • Goodfellas
  • China Girl
  • Heman
  • Poison
  • China Town
  • Tango and Cash

Drug Schedule

Fentanyl is a Schedule II drug, meaning that there are some medical purposes that a doctor may prescribe it for. However, it is highly addictive and is meant to be restricted to prevent dependence or substance use disorder.5

Factors that Determine How Long Fentanyl Stays in Your System

Several different factors determine how long fentanyl might stay in your system. Not only do the amount, tolerance, and type of drug matter, but other factors such as body mass and metabolism can change the fentanyl timeline.

Type of Drug

Fentanyl is a synthetic opioid analgesic. It is used as a painkiller to help with severe injuries or chronic pain. A person can take prescription fentanyl one of three ways: patches, tablets, and films. However, some people might inject it or snort the drug.6

Amount of Drug

The amount of the drug inside of someone’s system determines how much of it can be metabolized at one time. The liver breaks down fentanyl into a chemical called norfentanyl which then travels through the kidneys and exits the body.

Fentanyl Half-life

The half-life of a drug is how long it takes for the body to metabolize half of the drug. The average fentanyl half-life is around three hours. However, if someone uses a patch, the half-life could be anywhere from eight to seventeen hours. There are other ways of tracking fentanyl usage such as testing for metabolites

Body Mass

The size of a person regarding both height and weight can have an impact on how quickly they can break down fentanyl. A bigger person may have a slower metabolism rate, meaning it will take longer to break down. However, a smaller person would have a higher percentage of the drug in their body, meaning they might feel the effects quicker.

Metabolic Rate

Your body relies heavily on the liver and the kidneys to break down substances and to get them out of your system. Therefore, slower metabolic rates can slow down the process of breaking down fentanyl. Additionally, liver or kidney problems can lead to a longer period when it comes to breaking down fentanyl.6

How Long Does Fentanyl Stay in Your System?

On average, scientists can detect fentanyl in one’s system for up to four days. The main ways that people test for fentanyl is through blood testing, urine testing, and hair testing.

Blood Testing

When taking a blood test, doctors are normally looking for signs of fentanyl or norfentanyl within the body’s system. They can normally track fentanyl in the system for up to two days after the last use.6

Urine Testing

A very common drug test that employers might use is a urine test. Depending on one’s metabolic rate and body mass, it can range anywhere from twenty-four to seventy-two hours after the last use.6

Hair Testing

Finally, hair testing is an effective way to drug test an individual. Hair molecules keep track of things for longer, so doctors will be able to find fentanyl within the system for up ninety days after the last time it was used.

False-positive Testing

With any chance, there is always a risk for a false positive. Sometimes, drugs such as Benadryl can “trigger a false positive.”6 The best way to avoid this issue is by letting an employer know any medications that you have been prescribed or are currently taking to prevent any doubt.

How to get Fentanyl Out of Your System?

The only way to get fentanyl out of your system is by stopping your intake of the drug. You must give your body time to break down the chemical and metabolize it.

There are a few myths that drinking a lot of water or exercising will help, but there is no research that backs those myths up. The only way to get rid of the drug is by allowing your body to naturally break it down.


When a person stops using fentanyl, it can send them into withdrawal. Fentanyl withdrawal is a broad term for the symptoms that someone faces once they stop taking the drug. Withdrawal is extremely uncomfortable, and it is essential to seek out medical help if you are facing severe withdrawal symptoms. Some of these symptoms are as follows:7

  • Runny nose
  • Sudden rise in pain
  • Chills/sweating
  • Nausea
  • Muscle aches, pains, cramps, and twitches
  • Increased heart rate
  • Sleep issues
  • Suicidal thoughts or ideation
  • Moodiness/mood swings
  • Anxiety

Fentanyl Side Effects

fentanyl side effects iris healing

There are several side effects of fentanyl, including both short-term and long-term effects.


Some short-term effects are as follows:8

  • Constipation
  • Exhaustion
  • Insomnia or sleep issues
  • Cold chills
  • Dry or “cotton” mouth
  • Burning and tingling sensations
  • Memory loss
  • Lack of strength
  • Strange dreams
  • Sexual issues and problems


Several long-term effects can settle in when someone chronically uses fentanyl, including:8

  • Urination issues
  • Depression/anxiety
  • Bloating
  • Increased confusion
  • Troubles breathing
  • Tremors
  • Unusual, rapid weight loss or weight gain
  • Agitation
  • Migraines
  • Fevers
  • Hives
  • Extreme coughing
  • Nausea
  • Exhaustion
  • Chest tightness
  • Mania

Not everyone will experience these types of side effects, and some of the effects will come and go. Most importantly, if you or someone you love develops clammy skin, seizures, a slowed heartbeat, breathing issues, or an inability to speak due to drowsiness, seek medical attention right away. These issues are possible signs of an overdose, and you must seek out emergency services in this scenario.8

Treating Fentanyl addiction

Individuals struggling with fentanyl addiction go through a medication-assisted treatment that involves taking medication to lower withdrawal effects. They may also attend different types of therapies. By using both of these tools together, clients can identify things that trigger them to use fentanyl and form healthier coping mechanisms.9

Medication-Assisted Treatment

Studies have shown that medication-assisted treatment is effective in helping people recovery from fentanyl use disorder. Some of the medications a doctor might use include buprenorphine or methadone, as these medicines help reduce cravings. This treatment will often take place alongside cognitive behavioral therapy, so a client can uncover healthier ways to cope with life.9


The detox process from fentanyl can be challenging. Because it is so addictive, it is best to seek detox under the supervision of a healthcare professional. During this time, one will quit using fentanyl, allowing the body to heal.

A doctor might suggest staying in a residential facility while going through the detox and recovery process. Because fentanyl is an opiate, it is extremely addictive, and so it is beneficial for a person to check into a residential treatment facility. At a treatment facility, an individual will be surrounded by healthcare professionals that can help them.

CBT helps someone learn how to modify their bad habits such as fentanyl use and turn that behavior into something else. This way of therapy helps a patient learn how to manage stress and triggers as well as their lives and recovery. Therapy works very well when it comes to helping someone find sobriety from fentanyl.9


When employers drug test, they tend to check to see how much fentanyl is in someone’s system. It is important to seek help if you are struggling with this drug because it can have fatal consequences. If you or a loved one are struggling with substance use disorder, please contact your healthcare provider today.

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