How Long Does Fentanyl Stay in Your System?

As fentanyl can be administered in a myriad of ways, the form of ingestion determines its half-life and how long the effects last. The weight, urine volume, duration or frequency of usage, and compromised kidney or liver function can all be the determining factors on the question: how long does fentanyl stay in your system?

1. What Is Fentanyl?

Fentanyl is a potent synthetic opioid analgesic with up to 100 times more efficacy than other opioid analgesics like morphine. It is a Schedule II prescription medication typically used to treat severe pain or pain management after surgery in patients.

Fentanyl is often marketed under Duragesic, Sublimaze, and Actiq in its prescribed form. It is also used to treat patients suffering from chronic pain who are physically sensitive to other opioids.

It is used recreationally, sometimes in combination with heroin, THC, methamphetamine, or cocaine–which is then turned into pills that appear to be similar to other commonly prescribed opioid pain medications. These synthetic opioids are also known as Illicitly Manufactured Fentanyl (IMF).

According to forensic medical experts, this category of drugs has seen a drastic rise in use and sale in the past two decades, which points to a disturbing trend. IMFs are known and sold by various street names, including Captain Cody, Goodfella, Schoolboy, China White, dance fever, and so on.

2. Fentanyl’s Mechanism of Action

The opioid system is in charge of pain, pleasure, and addictive behavior. It comprises three G protein-coupled receptors, mu- (morphine receptors), delta1-, and kappa (k-receptors), through which the opioids act biochemically.

The opioid receptors in the brain are triggered by a class of endogenous peptides generated by neurons, such as β-endorphin, enkephalins, and dynorphins.

What Is Fentanyl? #fentanyl #drugabuse

Fentanyl and its compounds activate the opioid receptors in the brain, with a significant response coming from the activation of µ-opioid receptors (MORs), which is the most common receptor sub-type involved in pain signaling. Fentanyl alters how your body experiences and responds to pain by acting on the brain.

Apart from the clinical analgesic properties, the mu-opioid receptor agonists (or the drugs that activate specific biological receptors in your brain) may also result in several different side effects, including constipation, nausea, trembling, euphoria, and respiratory depression which can be fatal.

The delta-opioid receptors may lead to cognitive impairment, depression, severe drowsiness, and slow heart rate as some of its side effects. In contrast, kappa or k- opioid receptors regulate the potent analgesic and biochemical action of the opioids where the side effects may include vomiting, addiction, and sedation.

Fentanyl, unlike other opioids, produces little to no histamine (a trigger for allergies like mold, pollen, etc.), and it is rarely associated with low blood pressure or vomiting. In hypovolemic patients with severely low blood plasma content, it is a safer option than morphine and hydromorphone.

3. Overdose on Fentanyl

Fentanyl and other synthetic opioids are frequently linked to fatalities due to accidental usage or intentional drug misuse. Even in modest dosages, it can prove to be lethal.

According to the National Center for Health Statistics (NCHS) estimates, more than 150 people die every day from an overdose caused by synthetic opioids such as fentanyl.

Medical practitioners have used a variety of short and long-acting opiates to address the issue of inadequately treated pain. While this has helped prevent breakthrough pain, some patients do not adhere to proper dosing. Moreover, it often leads to toxicity concerns when the patient resorts to self-medication and increases the dose or duration of opioids.

How the powerful opioid fentanyl kills

 3 major signs for identification of an opioid overdose according to WHO:

  1. smaller, constricted pupils
  2. losing consciousness
  3. breathing problems

Some of the significant side effects and complications of a Fentanyl overdose include seizures, dizziness, menstrual or sexual health concerns, hallucinations, and itching or rashes on the skin.

In case of an overdose, speak with your doctor to keep Naloxone ready if you already notice the symptoms. Naloxone is a medication used to counteract and block the lethal effects of an excessive level of opiates in the blood.

4. Signs of Fentanyl Addiction

Opioid drug use poses a substantial risk of addiction in some people, even with a proper prescription and appropriate medication dosages. Opioid addiction is often marked by a strong, uncontrollable urge to use opioid drugs, even when they are no longer clinically viable.

Science Behind Addiction: Fentanyl

Below are the signs and symptoms associated with Fentanyl addiction or dependence:

  • Fentanyl is consumed in larger quantities or for more extended periods than prescribed, especially in the case of recreational uses.
  • The patient cannot lead an everyday life at home or work due to continuous fentanyl usage.
  • Despite the numerous after-effects impacting their daily lives, the person cannot quit taking the drugs.
  • A considerable chunk of time and money is spent acquiring the drugs and recovering afterward.
  • The individual is experiencing fentanyl cravings or urges.

5. How To Prevent Overdose

Fentanyl test strips (FTS) are a low-cost, easy-to-use, and scientifically proven drug testing technique for preventing narcotic overdose. FTS are small strips of paper less than 2 inches that may help identify fentanyl in any batch of the drug, including powder, pills, and injections.

To detect IMFs in street-sold drugs, local organizations striving to serve their community have begun distributing fentanyl test strips (FTS) as part of their awareness efforts and outreach programs.

In April 2021, a press release by the Substance Abuse and Mental Health Services Administration (SAMHSA) and the Centers for Disease Control and Prevention (CDC) announced that the public health departments can now use federal funding to buy fentanyl test strips apart from the usual drug tests, as part of their long-term campaign to prevent fentanyl overdose and the opioid epidemic.

6. Routes of Exposure

Do You Know How Fentanyl Works?

Exposure to fentanyl might be fatal, even in small quantities. It could be used to render a person debilitated and limit their capacity to function properly. The effects of fentanyl drug abuse on both the central nervous system (CNS2) and respiratory function can be detrimental.

  • Fentanyl can be released as small particles or liquid spray into indoor air.
  • Fentanyl can pollute water.
  • Fentanyl has the potential to contaminate food.
  • Fentanyl can be dispersed outdoors as small particles or as a liquid spray.
  • Fentanyl can contaminate farm produce as tiny particles or a liquid spray (aerosol).
  • It can enter the body through inhalation, oral intake or ingestion, or skin contact. It can be inserted or injected through veins (intravenously), through muscles (intramuscularly), or through fentanyl patches (transdermally).

7. How Long Does Fentanyl Stay in Your System?

The liver breaks down fentanyl into nor fentanyl, which is eliminated primarily through the kidneys. A study on the metabolites of fentanyl reveals that it can be detected in urine up until 72 hours, after which it’s undetectable, while fentanyl could be detected from 48 hours up until 96 hours. The findings of this study suggest that saliva testing does not provide a viable replacement for urine tests.

The effects of fentanyl may be felt for only a few hours, but the traces of the drug linger in your bloodstream for much longer and can be detected by drug tests. Furthermore, the weight, urine volume, duration and frequency of usage, and compromised kidney or liver function can all have an impact on how long fentanyl stays in your system.

  1. Blood tests – Fentanyl can be detected through a blood test 5 to 48 hours after the last exposure.
  2. Urine test – Fentanyl can be detected through a urine test 1 to 3 days after the last exposure.
  3. Hair tests – This is a rarely used method, although hair tests can detect fentanyl usage up to 3 months after the last known exposure.

8. How Can You Stop Taking Fentanyl?

QUIT FENTANYL in 3 DAYS! This is How You Do It

Fentanyl 3abuse may cause the neurotransmitters in your brain to stop functioning normally, resulting in an increased dependence on the drug influence. In case you suddenly stop taking fentanyl, opioid withdrawal symptoms might set in as the brain tries to regain its balance.

The effects may keep increasing for the first 12 to 30 hours, as per the USFDA, and they may last up to 72 hours after the last dosage.

Tapering, often known as weaning off the drug, is the gradual withdrawal of fentanyl over a specified length of time. It is performed under the direct supervision of a health professional for fentanyl addiction treatment and may help you get over your opioid 4withdrawal symptoms safely.

8.1. Treatment & Prescription Drugs

According to recent reports, fentanyl kills more people in America in the age group 18 and 45 than coronavirus and is now the No.1 cause of overdose deaths among United States adults. If you or someone near you has experienced fentanyl overdoses and/or is experiencing withdrawal symptoms, you must seek medical help at once.

Ketamine To Get Off Fentanyl! Ketamine stops withdrawal.

As part of the medical treatment, your doctor may prescribe a dose of Naloxone5, the safest option that completely blocks the opioid receptors and reverses the respiratory depression and other side effects of opioids.

If the patient does not respond satisfactorily to Naloxone, they may be referred to a nearby treatment provider for proper ventilation support, maintenance of blood pressure, and oxygenation to prevent further complications.

Methadone and buprenorphine target the same brain areas that opioids do to help alleviate withdrawal symptoms.

9. Conclusion

Fentanyl is a potent synthetic opioid analgesic that is primarily used as a pain medication. It belongs to the class of drugs known as opioids, which also includes substances like morphine and heroin. Fentanyl is estimated to be about 50 to 100 times more potent than morphine, making it a highly powerful painkiller.

It may be used for chronic pain management, breakthrough pain, and surgical procedures. Fentanyl is available in various forms, including transdermal patches, lozenges, tablets, nasal sprays, and injectable formulations.

It’s important to note that fentanyl is a controlled substance due to its high potency and potential for misuse. In recent years, there has been a concerning rise in illicitly manufactured fentanyl, which is often mixed with other drugs or sold as a counterfeit version of other opioids like oxycodone or heroin.

Illicit fentanyl is frequently associated with drug overdose deaths, as its potency increases the risk of respiratory depression and overdose.


1.  Is fentanyl addictive?

A: Yes, fentanyl is highly addictive. Its potent nature increases the risk of physical and psychological dependence. Misuse or recreational use of fentanyl significantly increases the chances of addiction.

2. What are the side effects of fentanyl?

A: Common side effects of fentanyl may include drowsiness, nausea, constipation, dry mouth, headache, and confusion. Serious side effects can include respiratory depression, low blood pressure, and slowed heart rate.

3. How can fentanyl overdose be treated?

A: The treatment for a fentanyl overdose typically involves administering naloxone, which is an opioid antagonist that can reverse the effects of an opioid overdose. Emergency medical services should be contacted immediately in case of a suspected overdose.


Read more
  1. Shiehzadegan, Shayan, et al. “Analysis of the delta variant B. 1.617. 2 COVID-19.” Clinics and practice 11.4 (2021): 778-784. ↩︎
  2. Giovannoni, Federico, and Francisco J. Quintana. “The role of astrocytes in CNS inflammation.” Trends in immunology 41.9 (2020): 805-819. ↩︎
  3. Kelly, Eamonn, et al. “The anomalous pharmacology of fentanyl.” British journal of pharmacology 180.7 (2023): 797-812. ↩︎
  4. Strang, John, et al. “Opioid use disorder.” Nature reviews Disease primers 6.1 (2020): 3. ↩︎
  5. Smart, Rosanna, Bryce Pardo, and Corey S. Davis. “Systematic review of the emerging literature on the effectiveness of naloxone access laws in the United States.” Addiction 116.1 (2021): 6-17. ↩︎

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