What is Fentanyl?

hand holding a bottle of fentanyl and a syringe

The Bottom Line

Fentanyl is a powerful opioid pain medication as well as a common contaminant found in illicit drugs. It can cause users to stop breathing, resulting in death. The antidote naloxone (Narcan) can reverse the effects of a fentanyl overdose if given in time.

woman's hand reaching for pills

What is fentanyl?

Fentanyl is a synthetic opioid medication. It was created in 1959 in an attempt to find safer and more effective alternatives to existing pain medications. Fentanyl was introduced into the US as an intravenous drug but is now available in oral, nasal, injectable, and skin patch formulations. More recently, fentanyl has become prevalent in the illicit drug supply and is the major cause of overdose deaths in the US. There are also several other compounds related to fentanyl that have been found in the drug supply. These are known as fentanyl derivatives and include chemicals such as carfentanil. 

What is fentanyl used for?

Fentanyl is used to treat various types of pain. It can be used in the form of a patch for chronic pain, such as cancer-related pain, as well as in other forms to treat acute and breakthrough pain (when a patient’s routine pain medicine is insufficient). 

What does fentanyl do?

Like other opioid drugs, fentanyl acts on the brain to cause pain relief but also sedation and euphoria (the sensation of feeling high). This is because fentanyl can move from the blood into the brain quickly. Fentanyl causes respiratory depression—slowing of the breathing rate—which makes it dangerous in overdose settings. Fentanyl is approximately 100 times more potent than morphine. Because it is so strong, even a very small amount can cause rapid and severe respiratory depression that can lead to death.  

Is fentanyl addictive?

Fentanyl is very addictive when misused or abused. Initial reports of fentanyl abuse were linked to prescription products, but in recent years, illicit fentanyl has become the most commonly abused form. In fact, most fentanyl-related deaths are from fentanyl made in illegal laboratories. Fentanyl is heavily trafficked into the US from other countries and sold as pills or powders, and it has largely replaced heroin in the drug supply. In some cases, these illicit formulations of fentanyl are made to look like other prescription opioid tablets. 

In 2022, the US Drug Enforcement Agency seized brightly colored fentanyl pills and powder ("rainbow fentanyl"), demonstrating that fentanyl can come in various colors and formulations. Because fentanyl is a common contaminant in illicit drugs such as heroin, cocaine, and methamphetamine, people who purchase, use, or sell street drugs may be completely unaware that a particular powder or pill contains fentanyl instead of the intended drug. 

There is no way to tell how much fentanyl might be present in a particular street drug. One way to reduce the risk associated with fentanyl contamination of illicit drugs is by using fentanyl test strips, now available in many communities as a harm reduction measure. These test strips can show if fentanyl is present in a drug prior to use. Fentanyl can also be contaminated with a veterinary sedative, xylazine, which can make it even more dangerous.

For people who are addicted to fentanyl, there are safe and effective treatments available. Scientists are also working on opioid vaccines that would cause a person to develop antibodies to particular opioids and block their effects. This would offer a new approach to treating substance abuse, but the results of this research will likely not be known for years to come.

What is a fentanyl overdose?

Because fentanyl is so potent and commonly found in the drug supply, it is easy for people to accidentally overdose on fentanyl. A fentanyl overdose can occur after the drug is injected, swallowed, snorted, or smoked. Symptoms of a fentanyl overdose, including slow or absent breathing, generally occur within minutes of the overdose. Death can follow quickly if the overdosed person isn’t treated.

How long does fentanyl last in your system?

Fentanyl can last for a few hours when taken orally or when snorted, smoked, or injected. The transdermal patches can last for up to 12 to 24 hours after the patch has been removed. While some urine drug screens can detect fentanyl, others do not. People can test positive for fentanyl for 3 to 5 days after last use. 

Can a fentanyl overdose be treated?

Naloxone (Narcan) is an antidote for fentanyl and other opioid overdoses. Naloxone helps reverse the respiratory depression of fentanyl. It can be given as a nasal spray or by injection. Naloxone can help prevent fentanyl-related deaths when it is given within a short period of time after an overdose. The nasal spray form of naloxone does not require a prescription and can be obtained from pharmacies. It is safe and easy for bystanders to administer. Naloxone acts quickly to reverse the effects of an opioid overdose, but opioids last much longer than naloxone. Additional doses of naloxone are therefore sometimes necessary. 

People who receive naloxone still require an emergency medical evaluation, as overdose symptoms can return. If someone who has overdosed does not have a pulse, start CPR. Once the heart and brain have gone without oxygen for a while, naloxone will not work. This is why it is so important to administer naloxone as soon as possible. 

What should I do if someone took fentanyl? 

If someone took fentanyl, the most important thing to do is call 911 and get them immediate medical attention. In the meantime, if the person is not breathing, you can administer bystander naloxone if it is available. If the person does not have a pulse, start CPR. 

If you have questions about poisoning from opioids, including fentanyl, contact Poison Control for expert advice. Get an immediate personalized recommendation online or call 1-800-222-1222. Both options are free, confidential, and available 24 hours a day.

Kelly Johnson-Arbor, MD
Medical Toxicologist

Revised William G. Troutman, PharmD
Professor of Pharmacy Emeritus

Revised Maryann Amirshahi, PharmD, MD, MPH, PhD
Medical Toxicologist 

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Poisoned?

Call 1-800-222-1222 or

HELP ME online

Prevention Tips

  • Do not use street drugs or other illicit substances.
  • Do not take medications that are not prescribed for you.
  • Even used fentanyl patches contain enough medication to harm a child. Be sure to discard these medications properly.
  • If you or a loved one have been prescribed an opioid pain medication, ask your doctor about getting naloxone (Narcan) from your pharmacy or learn how to obtain naloxone online.
  • Bystander naloxone administration saves lives. Learn how to administer naloxone and keep it handy if possible.
  • If a person does not have a pulse, perform CPR. 
  • There are safe and effective treatments for opioid addiction. Treatment for opioid dependence is the best way to prevent an overdose.

This Really Happened

Case 1. A 17-year-old boy was found unresponsive, with pinpoint pupils and a slow respiratory rate. He was treated by EMTs with naloxone, and his mental status and respiratory rate improved. He was admitted to an intensive care unit for observation. His brother reported that the boy had taken a blue tablet labeled “M30,” which the boy believed to be oxycodone. A urine test was positive for both fentanyl and cocaine (from Joynt & Wand, 2021).

Case 2. An 11-month-old girl swallowed a blue tablet she found while crawling around a new apartment. She became drowsy and had a slow breathing rate. She was treated with naloxone on the way to a hospital. Additional testing was positive for fentanyl, methamphetamine, acetaminophen, and tramadol (from Joynt & Wand, 2021).

Case 3. A 26-year-old man with a history of fentanyl abuse was found unresponsive in a gas station bathroom. Bystanders administered naloxone and performed CPR until an ambulance arrived. He was taken to a hospital, where he spent 3 days in the intensive care unit. He went on to recover and was discharged to a rehabilitation program. 

Case 4. A couple purchased some marijuana and smoked it on their couch. The woman woke up on the floor several hours later and found her partner unresponsive. She called EMS, and they were brought to an emergency room. She tested positive for fentanyl. Her partner was pronounced dead, and his autopsy also showed fentanyl in his blood. The woman made a full recovery.


For More Information

Counterfeit pills. Drug Enforcement Administration. Accessed March 1, 2024.

DEA warns of brightly-colored fentanyl used to target young Americans. Drug Enforcement Administration. Updated October 12, 2022. Accessed March 2, 2024.

Fentanyl drug facts. National Institute on Drug Abuse. June, 2021. Accessed March 1, 2024.

Fentanyl. Drug Enforcement Administration. April 2020. Accessed March 1, 2024.

How to test your drugs using fentanyl test strips. New York City Health Department. Accessed Mach 1, 2024.

Lifesaving naloxone. Centers for Disease Control and Prevention, Reviewed April 21, 2023. Accessed March 1, 2024.


References

A shot against opioids. National Institute on Drug Abuse. Updated October 18, 2023. Accessed March 2, 2024.

Armenian P, Vo KT, Barr-Walker J, Lynch KL. Fentanyl, fentanyl analogs and novel synthetic opioids: a comprehensive review. Neuropharmacology. 2018;134(Pt A):121-132.

Fentanyl test strips: a harm reduction strategy. Centers for Disease Control and Prevention. Reviewed September 30, 2022. Accessed March 1, 2024. 

Joynt PY, Wang GS. Fentanyl contaminated "M30" pill overdoses in pediatric patients. Am J Emerg Med. 2021;50:811.e3-811.e4.

Lötsch J, Walter C, Parnham MJ, Oertel BG, Geisslinger G. Pharmacokinetics of non-intravenous formulations of fentanyl. Clin Pharmacokinet. 2013;52(1):23-36.

Moss MJ, Warrick BJ, Nelson LS, et al. ACMT and AACT Position Statement: Preventing Occupational Fentanyl and Fentanyl Analog Exposure to Emergency Responders. J Med Toxicol. 2017;13(4):347-351.

Pergolizzi JV Jr, Dahan A, Ann LeQuang J, Raffa RB. Overdoses due to fentanyl and its analogues (F/FAs) push naloxone to the limit. J Clin Pharm Ther. 2021;46(6):1501-1504.

Ramos-Matos CF, Bistas KG, Lopez-Ojeda W. StatPearls: fentanyl. National Library of Medicine. Updated May 29, 2023. Accessed March 1, 2024.

Zawilska JB, Kuczyńska K, Kosmal W, Markiewicz K, Adamowicz P. Carfentanil - from an animal anesthetic to a deadly illicit drug. Forensic Sci Int. 2021;320:110715.

Poisoned?

Call 1-800-222-1222 or

HELP ME online

Prevention Tips

  • Do not use street drugs or other illicit substances.
  • Do not take medications that are not prescribed for you.
  • Even used fentanyl patches contain enough medication to harm a child. Be sure to discard these medications properly.
  • If you or a loved one have been prescribed an opioid pain medication, ask your doctor about getting naloxone (Narcan) from your pharmacy or learn how to obtain naloxone online.
  • Bystander naloxone administration saves lives. Learn how to administer naloxone and keep it handy if possible.
  • If a person does not have a pulse, perform CPR. 
  • There are safe and effective treatments for opioid addiction. Treatment for opioid dependence is the best way to prevent an overdose.

This Really Happened

Case 1. A 17-year-old boy was found unresponsive, with pinpoint pupils and a slow respiratory rate. He was treated by EMTs with naloxone, and his mental status and respiratory rate improved. He was admitted to an intensive care unit for observation. His brother reported that the boy had taken a blue tablet labeled “M30,” which the boy believed to be oxycodone. A urine test was positive for both fentanyl and cocaine (from Joynt & Wand, 2021).

Case 2. An 11-month-old girl swallowed a blue tablet she found while crawling around a new apartment. She became drowsy and had a slow breathing rate. She was treated with naloxone on the way to a hospital. Additional testing was positive for fentanyl, methamphetamine, acetaminophen, and tramadol (from Joynt & Wand, 2021).

Case 3. A 26-year-old man with a history of fentanyl abuse was found unresponsive in a gas station bathroom. Bystanders administered naloxone and performed CPR until an ambulance arrived. He was taken to a hospital, where he spent 3 days in the intensive care unit. He went on to recover and was discharged to a rehabilitation program. 

Case 4. A couple purchased some marijuana and smoked it on their couch. The woman woke up on the floor several hours later and found her partner unresponsive. She called EMS, and they were brought to an emergency room. She tested positive for fentanyl. Her partner was pronounced dead, and his autopsy also showed fentanyl in his blood. The woman made a full recovery.