What you need to know
- Fentanyl is an extremely potent opioid and is involved in most overdose deaths in the U.S.
- It’s often unknowingly mixed with other illicit drugs, increasing the risk of overdose.
- Anyone can carry and administer naloxone—often sold as Narcan—to reverse an overdose from fentanyl or other opioids.
Fentanyl is a potent synthetic opioid. It’s up to 50 times stronger than heroin and 100 times stronger than morphine. While the drug is sometimes used safely in medical settings—for example, to assist with anesthesia or manage severe pain after surgery—using illicit fentanyl, or taking it in ways other than prescribed, carries a high risk of overdose.
Read on to learn how fentanyl affects the body, why it’s so dangerous, and how to reduce the risk of overdose.
What happens when you take fentanyl?
Dr. Ned Guirey Urbiztondo, an anesthesiologist and assistant professor at Northwestern’s Feinberg School of Medicine, uses a “lock and key” model to explain how fentanyl affects the brain.
“Your brain has special receptors, or ‘locks,’ called opioid receptors,” he tells Public Good News. “For most people, your body produces its own natural ‘keys’—these are natural chemicals like endorphins—that fit into a wide variety of locks anytime you need pain relief or feel pleasure. Fentanyl is an incredibly powerful synthetic key that fits into these same locks, but it’s much stronger than your body’s natural chemicals.”
When fentanyl floods the brain’s opioid receptors, it creates a euphoric “high” along with other effects like sleepiness, nausea, and confusion.
Using any opioid, including fentanyl, in a way other than prescribed can lead to opioid use disorder, a chronic medical condition that changes how the brain works. When someone becomes dependent on opioids, they may experience withdrawal symptoms if they stop or reduce use. These can include changes in body temperature, irritability, tremors, trouble sleeping, digestive problems, and intense cravings.
How is fentanyl used in medical settings?
Health care providers may administer or prescribe fentanyl to assist with anesthesia or manage severe pain from cancer, surgery, or a serious injury.
“Medical fentanyl is produced by legal pharmaceutical manufacturing, given at known doses, and prescribed or administered by clinicians, largely in controlled settings like hospitals,” says Noa Krawczyk, an assistant professor at New York University’s Grossman School of Medicine and associate director of the Center for Opioid Epidemiology and Policy.
Illicit fentanyl is different. It comes from unregulated sources and is taken at unknown doses.
“That unpredictability of the dose—or even that it is often mixed in other illicit drug supplies like cocaine or illicit painkillers—is what makes illicit fentanyl especially dangerous,” Krawczyk explains.
How do fentanyl overdoses happen?
Fentanyl can be dangerous if it’s obtained illegally or when it’s not taken as prescribed. Like other opioids, it slows breathing. In an overdose, breathing can become dangerously slow—or stop altogether. Fentanyl is involved in most overdose deaths in the U.S.
“The amount [of fentanyl] that can get someone their euphoric ‘high’ versus the amount that can kill a person is extremely narrow,” Urbiztondo says, warning that an overdose can happen in minutes. “Your inability to breathe can occur almost immediately, which renders you incapable of calling for help in time to save your life.”
Taking fentanyl alongside alcohol or other drugs—including some prescription and over-the-counter medications—further increases the risk of overdose. If you are prescribed opioids, talk to your health care provider about your medical history, other medications you take, and any substances you use.
Fentanyl is also often unknowingly mixed into other illicit drugs. People who inject, swallow, or snort drugs may ingest fentanyl without realizing it, leading to unexpected and potentially life-threatening effects.
Who’s at risk of a fentanyl overdose?
Anyone can overdose on fentanyl. Some people may face higher risk of developing OUD and overdosing, including people who have a history of substance use disorder, people who use other substances, and people with certain health conditions, like sleep apnea.
“People with low or reduced opioid tolerance—such as those new to opioids or those returning to the community after a period of abstinence after incarceration or rehabilitation—are at particularly high risk,” Krawczyk says.
How can I prevent an overdose death from fentanyl?
Anyone can carry and administer naloxone, a medication that reverses opioid overdoses. When opioids have slowed or stopped a person’s breathing, naloxone can help restore normal breathing and keep them stable until emergency services arrive.
Naloxone is often available for free through community centers, public libraries, and programs for people who use drugs. You can also buy naloxone without a prescription at pharmacies, grocery and convenience stores, and other retailers. A pack of two doses typically costs around $50.
“Having naloxone available is critical when combined with not using alone,” Krawczyk says. She also recommends the Never Use Alone hotline. It’s run by volunteers who monitor callers and alert emergency services if someone stops responding.
Fentanyl test strips are another overdose prevention tool. They allow people to check whether their drugs contain fentanyl, helping them make more informed decisions.
Test strips may be available for free through local community programs, or you can buy them online. Laws vary by state, so check whether they’re legal where you live before purchasing or carrying them. Learn how to use fentanyl test strips from NYC Health.
For more information, talk to your health care provider.
This article was supported by Life Unites Us, a health campaign that receives funding from the Pennsylvania Department of Drug and Alcohol Programs. Public Good News retains full editorial control over its reporting.